43 results on '"Zhao, Jie"'
Search Results
2. Effect of Electric Field on the Microstructure and Properties of NiAl Alloy Sheet Prepared by Foil Reaction Synthesis.
- Author
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Wang, Shuai, Wang, DongJun, Zhao, Jie, Qin, ShaoHua, Wei, WenQing, Zhai, Bin, Wang, ZhiNan, and Liu, Gang
- Subjects
ELECTRIC field effects ,MOLECULAR dynamics ,MICROSTRUCTURE ,ALLOYS ,ELECTRIC fields - Abstract
NiAl alloy sheet was successfully prepared using current-assisted sintering, thus verifying the possibility of preparing a NiAl thin-wall component by current-assisted sintering and foil/foil reaction synthesis. Ni/Al laminated sheets were obtained by annealing at 550 °C at 5 MPa for 0.5 h; uniform NiAl alloy sheets were fabricated by annealing at 1150 °C at 15 MPa for 20 min. The experimental results showed that current-assisted sintering significantly reduced the reaction temperature and reaction time. Microstructural characterization revealed that the inter-diffusion ability of Al atoms is considerably weaker than that of Ni atoms. Molecular dynamics simulation confirmed these experimental results and showed that this difference becomes significant under the action of an electric field. The mechanism of synthesis of Ni/Al laminated sheets using current sintering is mainly determined by the diffusion behavior of Ni atoms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Effects of Co on Microstructure, Mechanical Properties, and Corrosion Resistance of Ti-Nb-Zr-Co Biological Alloys
- Author
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Zhao, Jie, Ma, Fengcang, Liu, Ping, Liu, Xinkuan, Li, Wei, and He, Daihua
- Published
- 2020
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4. A Novel Method for Preparing Intermetallics/Superalloy Dissimilar Materials Using Current Sintering of Metallic Powders.
- Author
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Ning, Hanwei, Wang, Dongjun, Qin, Shaohua, Zhao, Jie, Wei, Wenqing, Liu, Ze, and Liu, Gang
- Subjects
HEAT resistant alloys ,CONSTRUCTION materials ,SINTERING ,POWDERS ,MICROSTRUCTURE - Abstract
Herein, a novel method is proposed to prepare the multimaterial composite component for aerospace applications using the current sintering. Two representative high‐temperature structural materials, the new potential intermetallic NiAl and the widely used Ni‐based superalloy K4202, have been employed to achieve the target. As shown by the results, a clean interface with almost no defects is successfully obtained in NiAl/K4202 alloy. Nevertheless, the existence of a continuous Cr(Mo) phase along the region leads to an insufficient bonding ability. To optimize the interfacial microstructure, a Ni foil is employed as the interlayer. The results indicate that the interlayer can hinder the intense diffusion of elements and prevent the abnormal growth of Cr(Mo) phases, which result in a considerable improvement of interfacial properties. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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5. Microstructure and Tribological Performance of Laser Cladding Ti2AlC Particle Reinforced Coatings on Ti6Al4V.
- Author
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Hua, Shi-Wei, Pang, Ming, Chen, Jie, Zhao, Jie, and Ji, Feng-Qin
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FRETTING corrosion ,COMPOSITE coating ,ADHESIVE wear ,WEAR resistance ,MICROSTRUCTURE - Abstract
By applying the TC4-Ti
2 AlC composite coatings to the Ti6Al4V substrate by laser, the wear resistance of the Ti6Al4V alloy was improved. Analysis was done on the composite coatings' microstructure, phase composition, microhardness, and tribological characteristics. According to the findings, coatings without defects can be created when Ti2 AlC content ranges between 5 and 15 wt.%. Furthermore, the coating without Ti2 AlC consisted of a α-Ti solid solution while coatings with Ti2 AlC included a α-Ti solid solution, hard phases of TiC and Ti3 Al, as well as a Ti2 AlC ceramic phase. During laser cladding, Ti2 AlC partially dissolved and turned into TiC and Ti3 Al, resulting in an average hardness of 371.61 ± 3.95 HV0.5 , 382.92 ± 3.61 HV0.5 , 388.91 ± 3.29 HV0.5 for the coatings with Ti2 AlC weight fractions of 5, 10, and 15%, respectively. These numbers were about 1.16 ~ 1.22 times the hardness of the titanium alloy matrix (320 ± 3.12 HV0.5 ). Besides, the Ti2 AlC lubricant and hard phases act synergistically to bring composite coatings better performances in wear resistance and friction reduction compared to the pure TC4 coating. The lowest coefficient of friction (0.382) (COF) and the greatest wear resistance (8.87 × 10−5 mm3 /N m) were obtained at the composition of TC4-10wt.%Ti2 AlC; more particularly, the wear resistance at TC4-10wt.%Ti2 AlC was 1.2–2.1 times that of pure TC4 coating. The principal causes of wear in a pure TC4 coating are adhesive wear and oxidation, however, these wear processes shift to minor abrasive wear and oxidation when assisted by oxide coatings, Ti2 AlC lubricant, and TiC, Ti3 Al hard phases. [ABSTRACT FROM AUTHOR]- Published
- 2023
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6. Effect of Solution Treatment on the Microstructure and Mechanical Properties of High-Borated Steel Composites.
- Author
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Li, Yong-Wang, Wang, Zhao-Jie, Liu, Hai-Tao, and Li, Gang
- Subjects
COMPOSITE plates ,MICROSTRUCTURE ,STAINLESS steel ,CONSTRUCTION materials ,HOT rolling - Abstract
High-borated stainless steels prepared via ingot casting and hot rolling have a relatively low ductility, which limits their use as structural and functional materials in fuel reprocessing systems. In this study, 2.1 wt.% B stainless steel composites were prepared by a novel method of hot-roll bonding and solution treatment using an ingot casting slab and two layers of boron-free stainless steel. The aim of this study was to determine the effect of solution treatment on the interfacial microstructure and mechanical properties of high-borated stainless steel composites. As expected, a high-borated stainless steel slab containing many brittle ceramic (Cr, Fe)
2 B-type particles was successfully hot-rolled and bonded with boron-free stainless steel slabs. Furthermore, metallurgical bonding was realized via the formation of ~ 50 μm wide transition regions by solution treatment, for which the mechanism was found to consist of recrystallization and diffusion-controlled reactions. The formation of transition regions enhanced the geometrical restriction effect. Neither delamination nor cracking was observed along the interfaces during a bending test of the composite plates. [ABSTRACT FROM AUTHOR]- Published
- 2023
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7. Microstructure damage of directionally solidified alloy turbine blade after service.
- Author
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WANG Qiankun, WANG Wei, CHI Qingxin, CAO Tieshan, CHENG Congqian, and ZHAO Jie
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TURBINE blades ,DIRECTIONAL solidification ,HARDNESS testing ,MICROSTRUCTURE ,ALLOYS ,GAS turbine blades ,AIRPLANE motors - Abstract
Turbine blades are the most demanding components in aircraft engines, and their performance is related to the safety of the whole engine. Due to the complex service environment and harsh service conditions of blades, various types of damage cannot be prevented in service. Therefore, it is of great engineering and economic significance to study the service damage of blades. In this paper, the directional solidification alloy turbine blade after actual service was selected as the research object. The cross section position of 80% upper height of the blade was intercepted, and the qualitative and quantitative microstructure analysis was carried out by SEM and EDS analysis. The results show that there are two different types of γ' phases in this leaf. One kind of γ' phase has small size and regular shape, the other has large size and irregular shape. The degree of microscopic damage among different parts of the blade is characterized with the help of dimensional distribution characterization of the γ' phase of each part, combined with the analysis of hardness testing of each part of the cross-section.The results show that the service conditions of different parts are different, and the degree of microstructure damage is different. In addition, matrix crack and coating crack in some parts of blade are summarized and analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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8. A Non-Flat Terrain Biped Gait Planner Based on DIRCON.
- Author
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Chen, Boyang, Zang, Xizhe, Zhang, Yue, Gao, Liang, Zhu, Yanhe, and Zhao, Jie
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BIPEDALISM ,ROBOTS ,GAIT in humans ,ROBOTICS ,MICROSTRUCTURE - Abstract
Various constraints exist in bipedal movement. Due to the natural ability of effectively handling constraints, trajectory optimization has become one of the mainstream methods in biped gait planning, especially when constraints become much more complex on non-flat terrain. In this paper, we propose a multi-modal biped gait planner based on DIRCON, which can generate different gaits for multiple, non-flat terrains. Firstly, a virtual knot is designed to model the state transitions when the swing foot contacts terrain and is inserted as the first knot of the target trajectory of the current support phase. Thus, a complete gait or multi-modal gaits sequence can be generated at one time. Then, slacked complementary constraints, which can avoid undesired trajectories, are elaborated to describe the coupling relationships between terrain information and bipedal motion for trajectory optimization based gait planning. The concrete form of the gait planner is also delivered. Finally, we verify the performance of the planner, as well as the structural design of our newly designed biped robot in CoppeliaSim through flat terrain walking, stairs terrain walking and quincuncial piles walking. The three experiments show that the gaits planned by the proposed planner can enable the robot to walk stably over non-flat terrains, even through simple PD control. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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9. Microstructure evolution and mechanical properties of the cladding layer of Ti-6Al-4V alloy depending on ultrasonic-assisted forging
- Author
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Guo-Fu Gao, Zi-Long Guo, Ting-Ting Su, Wang Yi, Zhang-Dong Li, and Zhao-Jie Yuan
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Cladding (metalworking) ,0209 industrial biotechnology ,021103 operations research ,Materials science ,Alloy ,0211 other engineering and technologies ,Titanium alloy ,02 engineering and technology ,engineering.material ,Microstructure ,Industrial and Manufacturing Engineering ,Forging ,020901 industrial engineering & automation ,Control and Systems Engineering ,Ultrasonic vibration ,engineering ,Ultrasonic assisted ,Ti 6al 4v ,Composite material - Abstract
The cladding layer of Ti-6Al-4V alloy was treated by traditional forging and ultrasonic-assisted forging with the self-made forging device. The forged titanium alloy cladding layer was characterize...
- Published
- 2020
10. Microstructure, mechanical properties and wear resistance of Ti particles reinforced AZ31 magnesium matrix composites.
- Author
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Ye, Junliu, Chen, Xianhua, Luo, Huan, Zhao, Jie, Li, Jianbo, Tan, Jun, Yang, Hong, Feng, Bo, Zheng, Kaihong, and Pan, Fusheng
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WEAR resistance ,MECHANICAL wear ,TENSILE strength ,INTERFACIAL bonding ,MAGNESIUM ,TITANIUM composites ,ALUMINUM composites - Abstract
The compromise between strength and plasticity has greatly limited the potential application of particles reinforced magnesium matrix composites (MMCs). In this work, the Ti particles reinforced AZ31 magnesium (Mg) matrix composites achieved simultaneous improvement in strength, elongation and wear resistance. The Ti particles reinforced AZ31 composites were fabricated by ultrasonic-assisted stir casting with hot extrusion. The results showed that a strong interfacial bonding was obtained at Ti/Mg interface because of the formation of semi-coherent orientation relationship of TiAl/Mg, TiAl/Al 2 Ti and Al 2 Ti/Mg interfaces. The as-extruded 6 wt.%Ti/AZ31 composite presented the best compressive mechanical properties and wear resistance with ultimate tensile strength, elongation and wear rate of 327 MPa, 20.4% and 9.026 × 10
−3 mm3 /m, obviously higher than those of AZ31 alloys. The enhanced mechanical properties were attributed to the grain refinement and strong interfacial bonding. The improved wear resistance was closely related to the increased hardness of composites and the formation of protective oxidation films. • Ti particles refine the grain size of Ti/AZ31 composites. • A strong interfacial bonding forms at Ti/Mg interface. • Ti/AZ31 composites get an increase in strength, elongation and wear resistance. [ABSTRACT FROM AUTHOR]- Published
- 2022
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11. Multistimuli-Responsive Microstructured Superamphiphobic Surfaces with Large-Range, Reversible Switchable Wettability for Oil
- Author
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Hujun Wang, Yunhong Liang, Zhihui Zhang, Zhao Jie, Xiujuan Li, Luquan Ren, Zuankai Wang, and Cui Zhenquan
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Materials science ,Nanotechnology ,02 engineering and technology ,Adhesion ,Large range ,Hexadecane ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,0104 chemical sciences ,Contact angle ,chemistry.chemical_compound ,chemistry ,Oil droplet ,General Materials Science ,Wetting ,0210 nano-technology - Abstract
The switchable wettability is essential for widespread applications in droplet manipulation, rewritable liquid patterning, fluid carrying, and so forth. However, it remains difficult to achieve the multistimuli-responsive, large-range, and reversible wetting switching especially for liquids with low surface tensions through surface topographical management. Here, we apply a simple and effective template-free self-assembly strategy to fabricate microstructured superamphiphobic surfaces that can reversibly switch the wetting performance for oil by transforming the surface morphology in response to multiple stimuli of magnetic fields and mechanical strains. Notably, the noticeably different wetting switching of oil triggered by different stimuli is demonstrated. The contact angles of hexadecane droplets on the as-prepared surfaces can be reversibly switched between 150 ± 1° and 38 ± 2° in response to mechanical strains. Furthermore, the underlying mechanism of wetting switching has been further elucidated using mathematical models. Interestingly, these switchable surfaces dramatically demonstrate the ability to transport oil droplets, without requiring lubricating liquid films. This work not only achieves the large-range and reversible wetting switching for oil but also opens new avenues for fabricating tunable superamphiphobic surfaces with transformable mushroom-like microstructures that can be easily extended to microstructure-dependent friction or adhesion control and used in other fields.
- Published
- 2019
12. Ultra-fine microstructure and excellent mechanical properties of high borated stainless steel sheet produced by twin-roll strip casting
- Author
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Zhao-Jie Wang, Hai-Tao Liu, Guodong Wang, Huang Xiaoming, and Yong-Wang Li
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Austenite ,Materials science ,Mechanical Engineering ,0211 other engineering and technologies ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,Brittleness ,Mechanics of Materials ,Ultimate tensile strength ,engineering ,General Materials Science ,Ingot ,Composite material ,Austenitic stainless steel ,Deformation (engineering) ,0210 nano-technology ,021102 mining & metallurgy ,Eutectic system - Abstract
High borated stainless steel sheets have been widely applied in the nuclear power industry because of good thermal neutron absorption property. However, the large and network-like borides existing around the austenite grains in the conventional ingot casting steel seriously deteriorate the hot workability and the mechanical properties at ambient temperature. In this work, we tried to acquire ultra-fine microstructure by sub-rapid solidification using a novel twin-roll strip casting technology so as to enhance the mechanical properties of 2.1%B austenitic stainless steel. Surprisingly, dispersive and very fine borides mostly smaller than 5 µm were produced in the as-cast microstructure without network-like distribution. The morphologies and crystal structure of borides as well as the stacking faults in borides were investigated in detail. After subsequent hot-rolling and solution treatment, ultra-fine borides were observed with more than 50% of which in a size range of 0.3–1.5 µm, significantly smaller than those of the conventional ingot casted and hot rolled steel. Benefiting from the ultra-fine borides, excellent mechanical properties which had not been reported were obtained. In particular, a total elongation of 14.1% was exhibited, which was twice as high as that of the conventional ingot casted and hot rolled steel. Thus a new structure-function combining high borated stainless steel sheet was achieved. The strengthening and plasticity increasing mechanism was discussed based on Hall-Petch relationship, Orowan mechanism and strain-hardening rate analysis. The fracture behavior in tensile deformation was studied in detail. A characteristic fracture process accompanied with the initiation and coalescence of cavities in austenite matrix was found. This work not only developed a new processing way to produce high borated stainless steel with excellent mechanical properties, but also provided a potential solution for some other hard-worked metallic materials with brittle eutectic phase.
- Published
- 2019
13. A Novel Method for Observing Tumor Margin in Hepatoblastoma Based on Microstructure 3D Reconstruction.
- Author
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Liu, Jie, Wu, XiongWei, Xu, Chongzhi, Ma, Mingdi, Zhao, Jie, Li, Min, Yu, QiYue, Hao, XiWei, Wang, GuoDong, Wei, Bin, Xia, Nan, and Dong, Qian
- Subjects
GLYPICANS ,HEPATOBLASTOMA ,IMAGE registration ,MICROSTRUCTURE ,DIGITAL images - Abstract
Objective: We investigated three-dimensional (3 D) reconstruction for the assessment of the tumor margin microstructure of hepatoblastoma (HB). Methods: Eleven surgical resections of childhood hepatoblastomas obtained between September 2018 and December 2019 were formalin-fixed, paraffin-embedded, serially sectioned at 4 μm, stained with hematoxylin and eosin (every 19th and 20th section stained with alpha-fetoprotein and glypican 3), and the digital images of all sections were acquired at 100× followed by image registration using the B-spline based method with modified residual complexity. Reconstruction was performed using 3 D Slicer software. Results: The reconstructed orthogonal 3 D images clearly presented the internal microstructure of the tumor margin. The rendered 3 D image could be rotated at any angle. Conclusions: Microstructure 3 D reconstruction is feasible for observing the pathological structure of the HB tumor margin. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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14. Synthesis, in vitro biocompatibility and antibacterial property of novel silk fibroin@Ag spheres.
- Author
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Zhang, Jianan, Zhao, Jie, Chen, Song, Jiao, Xiong, Li, Xiaona, and Chen, Weiyi
- Subjects
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SILK fibroin , *SILK , *GRAM-negative bacteria , *STAPHYLOCOCCUS aureus , *ESCHERICHIA coli , *BIOCOMPATIBILITY - Abstract
• Silk fibroin@Ag spheres were prepared by in situ deposition of Ag nanoparticles on silk fibroin spheres. • Silk fibroin@Ag spheres were not cytotoxic and biocompatible. • Silk fibroin@Ag spheres showed antibacterial activity against the growth of bacteria. In this study, novel silk fibroin@Ag spheres were synthesized by in situ growth of Ag nanoparticles (NPs) on silk fibroin (SF) spheres and their microstructure, in vitro biocompatibility, and antibacterial property were evaluated. SEM observation showed that SF@Ag spheres had a spherical morphology with a diameter of 1–10 µm. TEM observation revealed that each SF@Ag sphere had a dense structure and its surface was deposited with Ag NPs with a diameter of 10–50 nm. In vitro biocompatibility evaluation indicated that SF@Ag spheres were not cytotoxic when incubated with osteoblast MC3T3-E1 cells. Moreover, when exposed to two representative types of gram-negative Escherichia coli and gram-positive Staphylococcus aureus , SF@Ag spheres showed a good antibacterial property against the growth of both types of bacteria. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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15. Microstructural evolution and mechanical properties of titanium-alloying high borated steel sheets fabricated by twin-roll strip casting
- Author
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Zhao-Jie Wang, Hai-Tao Liu, Yong-Wang Li, Guodong Wang, and Weina Zhang
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Materials science ,020502 materials ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,Slip (ceramics) ,Brittleness ,0205 materials engineering ,chemistry ,Mechanics of Materials ,visual_art ,Volume fraction ,visual_art.visual_art_medium ,General Materials Science ,0210 nano-technology ,Ductility ,Boron ,Titanium ,Eutectic system - Abstract
High borated steels have been applied in the nuclear power industry as excellent neutron-shielding materials, but their ductility was relatively low due to the large and brittle borides, restricting their wider utilization. In this work, the high-performance borated steels containing 2.40 wt% B were fabricated through a designing combination of titanium-alloying along with twin-roll strip casting technology. It was found that titanium addition facilitated the increasing boron content of eutectic point for steels. The TiB2 particles solidifying firstly from molten steel depleted massive boron atoms in advance, leading to an as-cast microstructure consisting of more γ-Fe and less M2B-type borides comparing with titanium-free steels. Besides, TiB2 particles were 200–240 nm, and they could act as heterogeneous nucleation cores for M2B borides. Thus dispersive and fine M2B borides smaller than 5 μm were produced in as-cast microstructure. After subsequent hot-rolling and solution-treating, ultra-fine borides were obtained with more than 80% of which in a size range of 0.1–2 μm. In this case, the steels exhibited an excellent total elongation of 16.2% that was twice as high as that of titanium-free steels. Additionally, the relations between microstructure and mechanical properties of hot-rolled and solution-treated steels were clarified. The ductility of steels was determined by the volume fraction of γ-Fe matrix that could accommodate large deformation, but the strength of steels was dominated by the volume fraction of borides that provided the strengthening effects including grain refinement, load transfer term and hindering the dislocation slip. This work provided a new promising method to enhance the ductility of such high borated steels.
- Published
- 2021
16. Effects of hot rolled microstructure after twin-roll casting on microstructure, texture and magnetic properties of low silicon non-oriented electrical steel
- Author
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Zhao-Jie Wang, Jun-Mou Chen, An Lingzi, Dao-Yuan Hou, Guodong Wang, Yin-Ping Wang, and Hai-Tao Liu
- Subjects
010302 applied physics ,Fabrication ,Materials science ,Silicon ,Annealing (metallurgy) ,chemistry.chemical_element ,Recrystallization (metallurgy) ,02 engineering and technology ,engineering.material ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Grain size ,Electronic, Optical and Magnetic Materials ,chemistry ,0103 physical sciences ,engineering ,Composite material ,0210 nano-technology ,Electrical steel - Abstract
In this work, a 0.71 wt%Si+0.44 wt%Al as-cast strip was produced by novel twin-roll casting. Some as-cast samples were respectively reheated and hot rolled at different temperatures in order to obtain different microstructure prior to cold rolling and annealing. The effects of the hot rolled microstructure on microstructure, texture evolution and magnetic properties were investigated in detail. A coarse deformed microstructure with λ-fiber texture was formed after hot rolling at 850–1050 °C, finally leading to an inhomogeneous recrystallization microstructure with strong λ-fiber, Goss and extremely weak γ-fiber texture. By contrast, a fine transformed microstructure was formed after hot rolling at 1150–1250 °C, finally leading to a fine and homogeneous recrystallization microstructure with stronger α-fiber, γ-fiber and much weaker λ-fiber texture. It should be noted that both the magnetic induction and core loss non-monotonically decreased or increased according to the hot rolling temperature. The unfavorable α-fiber and γ-fiber textures in the annealed sheets were much weaker than those of the conventional products regardless of the hot rolling temperature, thus contributing to a much higher magnetic induction. However, the average grain size in the annealed sheets was much lower than those of the conventional products regardless of the hot rolling temperature, thus leading to a higher core loss except the case of 1050 °C. Hence, it is underscored that better integrated magnetic properties than those of the conventional products can be obtained by optimizing the hot rolled microstructure to produce final desirable recrystallization microstructure and texture.
- Published
- 2016
17. Effects of boron content on the microstructure and mechanical properties of twin-roll strip casting borated steel sheets
- Author
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Guodong Wang, Hai-Tao Liu, Zhao-Jie Wang, and Yong-Wang Li
- Subjects
010302 applied physics ,Microstructural evolution ,Materials science ,Morphology (linguistics) ,Mechanical Engineering ,Metallurgy ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Strip casting ,chemistry ,Mechanics of Materials ,0103 physical sciences ,General Materials Science ,0210 nano-technology ,Boron ,Eutectic system - Abstract
High borated steel sheets containing 0.25 wt% to 4.0 wt% boron including hypoeutectic (0.28 wt% B and 2.11 wt% B), eutectic (2.43 wt% B) and hypereutectic (4.01 wt% B) compositions were tried to be fabricated by a novel strip casting technology, and the effects of boron content on sub-rapid solidification behavior and subsequent microstructural evolution together with mechanical properties was studied. It was found that the morphology of borides depended greatly on the boron content. When increasing boron, the morphological change of borides was network-like → grainy → cluster-like → plate-like. Various orientation relationships between different morphological borides and γ-Fe in as-cast steels were also identified. After subsequent hot-rolling and solution-treating, ultra-fine (
- Published
- 2020
18. Microstructure, mechanical properties and springback behaviour of Ti‑6Al‑4V alloy connection rod for spinal fixation device
- Author
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Weiqiang Wang, Qiaochu Li, Bai Shuyu, Zhong Gongcheng, Zhao Jie, Bai Pengfei, Tao Xiaojie, and Min Xiaohua
- Subjects
Equiaxed crystals ,Materials science ,Annealing (metallurgy) ,Alloy ,Bioengineering ,02 engineering and technology ,engineering.material ,010402 general chemistry ,01 natural sciences ,Biomaterials ,Flexural strength ,Hardness ,Tensile Strength ,Ultimate tensile strength ,Materials Testing ,Alloys ,Composite material ,Titanium ,Titanium alloy ,021001 nanoscience & nanotechnology ,Microstructure ,Spine ,0104 chemical sciences ,Orthopedic Fixation Devices ,Mechanics of Materials ,Vickers hardness test ,engineering ,0210 nano-technology - Abstract
The effect of annealing condition on microstructure, mechanical properties and springback behaviour was examined in the connection rod of Ti-6Al-4V alloy for spinal fixation devices. Compared with the deformed microstructure in the sample before annealing, relatively few equiaxed grains were present after annealing at 1003 K after 1.8 ks, and a considerable amount appeared at 7.2 ks. When annealing time was extended to 36 ks, the recrystallised grains further grew. Vickers hardness, tensile strength and bending strength decreased with increasing annealing time, whereas the elastic and bending moduli showed no significant change with annealing time of up to 7.2 ks and then slightly decreased at 36 ks. The springback ratio was closely associated with strength and modulus and applied bending deflection. The springback ratio reached the highest and lowest values in the sample before and after annealing for 7.2 ks, respectively. A good combination of strength, modulus and springback ratio was obtained in the sample after annealing for 7.2 ks.
- Published
- 2017
19. Microstructure and Tensile Elongation Enhancement of 1.6 wt% B stainless Steel Plates Fabricated by Composite Rolling
- Author
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Liu Guangjun, Zhao-Jie Wang, Hai-Tao Liu, Xiaoming Zhang, Yong-Wang Li, and Bao-Guang Zhang
- Subjects
Materials science ,Composite number ,Materials Chemistry ,Metals and Alloys ,Steel plates ,Physical and Theoretical Chemistry ,Composite material ,Condensed Matter Physics ,Microstructure ,Tensile testing - Published
- 2019
20. Microstructure evolution and mechanical properties of the cladding layer of Ti-6Al-4V alloy depending on ultrasonic-assisted forging.
- Author
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Gao, Guo-Fu, Su, Ting-Ting, Li, Zhang-Dong, Wang, Yi, Guo, Zi-Long, and Yuan, Zhao-Jie
- Subjects
TITANIUM alloys ,FORGING ,MICROSTRUCTURE ,ALLOYS ,SCANNING electron microscopy ,MATERIAL plasticity - Abstract
The cladding layer of Ti-6Al-4V alloy was treated by traditional forging and ultrasonic-assisted forging with the self-made forging device. The forged titanium alloy cladding layer was characterized by scanning electron microscopy, and the hardness distribution of the counterparts was examined by Rockwell hardness tester. The reasons for the difference of microstructure under two different forging methods were analyzed, and the influences of ultrasonic amplitude and forging force on the microstructure were discussed. The results showed that the ultrasonic vibration-assisted forging process was more advantageous to the plastic deformation of titanium alloy cladding layer than the traditional forging process and was beneficial to the evolution of the original Widmanstatten structure to the duplex microstructure. Meanwhile, the hardness of titanium alloy cladding layer was improved by about 10%. Furthermore, with the increase of ultrasonic amplitude and forging force, the microstructure of titanium alloy cladding layer gradually changed to equiaxed microstructure with better properties. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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21. Microstructure and corrosion performance of X100 steel in the oilfield produced water.
- Author
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Zhao, Jie, Wang, Shengnan, Gu, Yanhong, Xiong, Dan, and Tian, Bin
- Subjects
- *
OIL field brines , *STEEL , *WATER temperature , *MICROSTRUCTURE , *OIL field flooding - Abstract
The corrosion performances of X100 steels in the oilfield produced water with different temperature (30°C, 40°C, 60°C) under the simulated working conditions were studied by potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) test. Energy dispersive spectroscopy (EDS) was used to measure the element composition of the sample after corrosion. The phase and chemical compositions of the specimens were analyzed by X-ray diffraction (XRD) and Raman spectrometry. The electrochemical results showed that the corrosion resistance of the specimen exposed for 24 hours increased with the increase of the testing temperature, indicating the better protective effect due to the corrosion product film formed under high temperature despite the impact of turbulence. The corrosion products consist of Fe3O4, Fe2O3, α-FeOOH, and γ-FeOOH. The corrosion mechanism model of X100 steel was established and the corrosion behavior was analyzed under simulated working conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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22. Recrystallization behavior during hot tensile deformation of TA15 titanium alloy sheet with substantial prior deformed substructures.
- Author
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Zhao, Jie, Wang, Kehuan, Huang, Ke, and Liu, Gang
- Subjects
- *
CRYSTAL grain boundaries , *TITANIUM alloys , *BEHAVIOR , *ANNEALING of metals , *MICROSTRUCTURE - Abstract
Dynamic recrystallization to a large extent determines the microstructure of near-α titanium alloys during the thermo-mechanical processing in α + β two phases zone. And the initial microstructure has a dramatic effect on the recrystallization behavior. Therefore, this paper deals with the recrystallization behavior of a near-α TA15 titanium alloy sheet with substantial prior deformed substructures during the annealing and hot tension at 800 °C. Undeformed and deformed regions of tensile samples, viz., static recrystallization and dynamic recrystallization, were studied respectively through EBSD observation. It was found that, the unusual intragranular nucleation of discontinuous recrystallization was observed in the relatively coarse grains, which was formed by the enclosed low angle grain boundaries rearranged by the thermally activated recovery. And most of the recrystallized grains manifested as three types of special grain boundaries, namely [0001]30°, 11 2 ¯ 0 75 ° and 13 8 ¯ 5 ¯ 3 90 ° , which showed the cusps in grain boundary energy and can stabilize the recrystallized grain embryo. The substantial prior deformed substructures of the employed TA15 sheet, viz., low angle grain boundaries and dislocations, can facilitate the formation of subgrains and nucleation, which brought about a mixture of continuous and discontinuous recrystallization, regardless of dynamic or static. During the hot tension, the activation of dislocations would accelerate the annihilation and rearrangement of dislocations, thus, recrystallization can take place more frequently, which finally leads to an equiaxed microstructure. • Quasi-in-situ annealing treatment of the initial TA15 sheet was carried out. • A mixture of continuous and discontinuous recrystallization was observed during annealing and hot tension. • Effect of substantial prior deformed substructure on the recrystallization behavior was investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
23. Effect of hot-dip siliconizing time on phase composition and microstructure of Mo–MoSi2 high temperature structural materials.
- Author
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Zhang, Yingyi, Zhao, Jie, Li, Jinghui, Lei, Jie, and Cheng, Xiangkui
- Subjects
- *
SILICONIZING (Metallurgy) , *MOLYBDENUM compounds , *EFFECT of temperature on metals , *CRYSTAL structure , *METAL microstructure - Abstract
Abstract Mo–MoSi 2 high temperature structural materials were obtained by hot-dip siliconizing method. The results show that the silicon melt and molybdenum substrate have good wettability, molten silicon reacts with molybdenum substrate to form a molybdenum silicide phase with a columnar structure, and a strong MoSi 2 crystallographic preferred orientation (CPO) on the (110) crystal face is characterized. While, the Mo–MoSi 2 high temperature structural materials consist mainly of silicon rich layer, MoSi 2 layer, interface layer and molybdenum substrate. The coating surfaces contain a high silicon concentration (55–65 wt%) than the MoSi 2 layer (30–35 wt%). Moreover, the thicknesses and the average grain sizes of siliconized coatings increase sharply with increasing siliconizing time. The coatings thicknesses are 20, 25, 30, and 50 µm, respectively. And the average grain sizes are 6.9, 9.3, 11.7, and 11.8 µm, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
24. Microstructural Evolution of Oxidation Film on a Single Crystal Nickel-Based Superalloy at 980 °C.
- Author
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Hu, Yebing, Cheng, Congqian, Zhang, Li, Cao, Tieshan, Guo, Guangping, Meng, Xianming, and Zhao, Jie
- Subjects
MICROSTRUCTURE ,HEAT resistant alloys ,SINGLE crystals ,NICKEL ,OXIDATION - Abstract
The isothermal oxidation behavior of a single crystal nickel-based superalloy was investigated at 980 °C through XRD, SEM/EDX and EPMA. The mass gain process exhibited two periods: an initial stage followed by a steady-state stage. Based on the experimental results, the rapid formation of alumina and NiO was responsible for the initial stage of mass gain, and the formation of complex spinels phases may dramatically effect on the steady stage. The microstructure of oxidation film, from the top surface down to the base material, was clarified as Ni-rich oxides, Ni-Cr oxides, Cr-Ta-Co oxides, Ni-Al oxides and finally a continuous Al
2 O3 . In addition, AlN formed in the γ′-free zone. The effect of oxidation film evolution on the oxidation kinetics and mechanism were discussed. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
25. Ultrathin, flexible, conductive silver nanowires@polyvinyl alcohol composite film fabricated via the combination of air plasma treatment and thermal sintering for electromagnetic interference shielding.
- Author
-
Li, Gang, Zhao, Jie, Wang, Zhuang, Yu, Xuecheng, Zhao, Tao, Liang, Xianwen, Sun, Rong, Cao, Liqiang, and Zhu, Pengli
- Subjects
- *
ELECTROMAGNETIC shielding , *ELECTROMAGNETIC interference , *THERMAL plasmas , *SINTERING , *SILVER - Abstract
• AgNWs@PVA composite films were fabricated via a unique combination method. • The AgNWs@PVA film shows high EMI SE of 55 dB at 11 μm ultra-low thickness. • The AgNWs@PVA film retains excellent stability after 2000 bending cycles. It remains still a challenge to prepare thin, flexible, conductive films for electromagnetic interference shielding, which are highly desired in next-generation electronic applications such as aerospace, medical and wearable devices, etc. Herein, silver nanowires@polyvinyl alcohol (AgNWs@PVA) composite films were fabricated via a unique combination of air plasma treatment followed by thermal sintering of AgNWs network. The prepared composite ultra-thin film (11 µm) with 24.2 wt% of AgNWs displays relatively low density of 1.58 g cm−3. Remarkably, the sheet resistance and electromagnetic interference shielding effectiveness are separately achieved to 0.29 Ω/sq and 55 dB at the measured frequency range of 8.2 GHz to 12.5 GHz. These traits underscore a significant promising prospect of AgNWs@PVA film in the modern flexible electronic devices. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
26. Analysing the Interaction between Microscopic Deformation, Microstructure and Void Evolution of Near-α Titanium Alloys during Non-Superplastic Hot Deformation by an Integrated Crystal Plasticity Finite Element Model.
- Author
-
Zhao, Jie, Wang, Kehuan, Lv, Liangxing, Wang, Liliang, Politis, Denis J., and Liu, Gang
- Subjects
- *
TITANIUM alloys , *FINITE element method , *MICROSTRUCTURE , *DEFORMATIONS (Mechanics) , *CRYSTAL grain boundaries , *CRYSTALS - Abstract
High-efficiency and low-cost hot forming technologies for titanium alloys have been developed for producing complex-shaped, thin-walled tubular components under non-superplastic forming conditions. Under these forming conditions, there exist complex and highly integrated material evolution processes including microscopic heterogeneous deformation, microstructure evolution and damage behaviour. This paper presents an integrated crystal plasticity finite element model of near-α titanium alloys during non-superplastic hot deformation conditions considering grain boundary sliding (GBS), dynamic recrystallisation (DRX), as well as void evolution. The polycrystalline model of a near-α TA15 titanium alloy was established, containing α phase, β phase and grain boundary (GB) regions, in which the GB region was a visualised representation of GBS. The quantitative strength ratio between the GB regions and α phase was calculated according to the Zener–Holloman parameter Z and grain size, which determined the microscopic deformation behaviour. There were found to be two high microscopic strain regions in the α phase: intragranular deformation bands through the most favourable slipping and near the GBs through multiple slipping, which promoted continuous and discontinuous DRX, respectively. With the decrease in parameter Z or grain size, the activated dislocations accommodating GBS were found to no longer pile up inside the grain, but instead travel across the grain interior. Finally, methods to improve the macroscopic plastic formability were proposed for the difficult-to-form titanium alloys experiencing non-superplastic hot deformation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
27. Effects of boron content on the microstructure and mechanical properties of twin-roll strip casting borated steel sheets.
- Author
-
Wang, Zhao-Jie, Li, Yong-Wang, Wang, Guo-Dong, and Liu, Hai-Tao
- Subjects
- *
BORON steel , *CAST steel , *SHEET-steel , *HYPEREUTECTIC alloys , *BORON , *MICROSTRUCTURE , *BORIDES - Abstract
High borated steel sheets containing 0.25 wt% to 4.0 wt% boron including hypoeutectic (0.28 wt% B and 2.11 wt% B), eutectic (2.43 wt% B) and hypereutectic (4.01 wt% B) compositions were tried to be fabricated by a novel strip casting technology, and the effects of boron content on sub-rapid solidification behavior and subsequent microstructural evolution together with mechanical properties was studied. It was found that the morphology of borides depended greatly on the boron content. When increasing boron, the morphological change of borides was network-like → grainy → cluster-like → plate-like. Various orientation relationships between different morphological borides and γ-Fe in as-cast steels were also identified. After subsequent hot-rolling and solution-treating, ultra-fine (<10 μm) borides were obtained in hypoeutectic and eutectic steels. Benefiting from that, excellent mechanical properties was achieved, which was much better than that of steels prepared by traditional ingot casting. Particularly, when the boron content approached eutectic composition, of which the effect on the microstructure and mechanical properties was more sensitive. The steels containing 2.11 wt% and 2.43 wt% boron exhibited different morphological borides with a total elongation of 14.1% and 8.0%, respectively. Moreover, a thin hypereutectic borated steel sheet was also prepared, but the borides were very large and the total elongation was very low. The correlation between microstructure and strength was clarified based on the Hall-Petch behavior and intermetallic strengthening effect. Smaller γ-grains and higher volume fraction of borides were responsible for higher strength. The plastic behavior of steels was influenced by strain-hardening rate that was determined by the volume fraction of γ-Fe matrix. A better sustainable strain-hardening capability was beneficial to extend the stage of uniform deformation and enhance the ductility. In addition, the mechanical properties of steels were also decided by the fracture mechanism that was dominated by the size of borides. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
28. Microstructure and Tensile Elongation Enhancement of 1.6 wt% B stainless Steel Plates Fabricated by Composite Rolling.
- Author
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Li, Yong‐Wang, Liu, Guang‐Jun, Wang, Zhao‐Jie, Zhang, Bao‐Guang, Zhang, Xiao‐Ming, and Liu, Hai‐Tao
- Subjects
MICROSTRUCTURE ,BORON steel ,TENSILE strength ,COMPOSITE plates ,MATERIAL plasticity - Abstract
A 3‐layered composite plate is innovatively fabricated via composite rolling of 1.6 wt% B stainless steel surrounded by two layers of boron‐free steels. The tensile properties of composite and non‐composite plates are comparatively tested and analyzed. Besides, the microstructure evolution of the investigated plates is characterized in detail. It is found that the composite specimens exhibit higher tensile elongation comparing with that of non‐composite specimens. Specifically, the engineering strain of the 1050 °C × 30 min solution‐treated specimens reaches to 12.5 ± 0.8% which is 2.5–3.0 times as high as that of non‐composite specimens. In addition, the as‐cast lamellar borides break into bar‐shaped structures in hot rolled plates, however, their morphology and distribution hardly change after solution treatment. Besides, the transition regions between the core and clad layers are formed and characterized by medium‐sized recrystallized grains and fine borides in the solution‐treated composite specimens. The enhancement mechanism of tensile elongation is mainly analyzed in term of the geometrical restriction of necking in the composite plate during tensile deformation. This paper provides a promising method to effectively enhance the tensile fracture elongation for these metallic materials with poor plasticity like high borated stainless steels. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Towards high strengthening efficiency of equiaxed and platelet-shaped alumina reinforced zirconia ceramics with textured microstructure using DLP-based stereolithography.
- Author
-
Wang, Yang, Zhou, Qingxuan, Han, Zhuoqun, Han, Yongning, Bi, Lunan, Zhang, Xia, Lu, Xiang, Zhao, Jie, Chu, Wei, Li, Jian, Zhao, Zhicheng, Wang, Yingying, Liu, Jia, Li, Ling, and Liu, Futian
- Subjects
- *
ALUMINUM oxide , *STEREOLITHOGRAPHY , *CERAMICS , *MICROSTRUCTURE , *FRACTURE toughness - Abstract
ZrO 2 –Al 2 O 3 (ATZ) ceramics are attracting high interest in biomedical applications because of their desirable mechanical performance and biocompatibility. However, strength and toughness are mutually exclusive in structural ceramics. In this paper, based on digital light processing, novel textured ATZ ceramics with obvious crystallographic orientations were fabricated by incorporating Al 2 O 3 platelets with a high aspect ratio and equiaxed particles into the ZrO 2 matrix. The optimized fracture toughness of 16.9 ± 0.8 MPa m1/2 was achieved in the textured ATZ ceramic, which was about 67.3 % higher than non-textured ZrO 2 ceramics, without sacrificing strength. The coupling toughening effects of macrolayer structure, equiaxed and platelet-shaped Al 2 O 3 particles, and ZrO 2 particles were responsible for the enhanced mechanical performance. The macroscale toughening of 3D-printed lamellar architecture led to effective energy dissipation. Additionally, the crack deflection and crack branching induced by dual-morphology Al 2 O 3 particles, accompanied by the phase transformation of the ZrO 2 matrix, were significant microscopic toughening mechanisms. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
30. Experimental and modelling study of an approach to enhance gas bulging formability of TA15 titanium alloy tube based on dynamic recrystallization.
- Author
-
Wang, Kehuan, Liu, Gang, Zhao, Jie, Huang, Ke, and Wang, Liliang
- Subjects
- *
TITANIUM alloy welding , *LASER welding , *METAL formability , *MICROSTRUCTURE , *RECRYSTALLIZATION (Metallurgy) - Abstract
In order to further improve the hot gas bulging formability of laser-welded TA15 titanium alloy tube, studies about the effects of initial microstructures on the formability were carried out at 800 °C. Vacuum annealing procedures were performed to obtain different microstructures. The formability of these TA15 titanium alloy sheets with different microstructures was subsequently investigated by hot tensile tests and hot gas free bulging. A unified physically based material model considering dislocation density, work hardening, recrystallization, grain size and damage was built to analyze the deformation process. Results show that a good agreement was achieved between the unified material model and experiment results. The evolution of physical variables such as recrystallization fraction, and grain size can be predicted properly by the model. In the unified material model, the initial dislocation density would affect the dynamic recrystallization (DRX) rate. The DRX rate would increase with the increasing dislocation density. Therefore more DRX occurred at the early stage of deformation of initial material with higher dislocation density, while most of the DRX occurred at the middle-late stage of deformation of the annealed material with lower dislocation density. The initial material demonstrated the best formability due to the wide occurrence of DRX at the early stage of deformation, which increased the fraction of high angle grain boundaries, refined the microstructure, promoted the occurrence of grain boundary sliding and enhanced the formability of the material. However, most of the DRX occurred at middle-late stage of deformation of annealed material, which may increase the softening rate and lower the formability. Hence increasing the occurrence of DRX at the early stage of deformation by increasing the initial dislocation density in the material is an efficient approach to improve the gas bulging formability. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
31. Grain boundary migration-induced directional coarsening of the γʹ phase in advanced ultra-supercritical superalloy.
- Author
-
Li, Huifang, Ye, Fei, Zhao, Jie, Cao, Tieshan, Xu, Fanghong, Xu, Qingshuang, Wang, Yan, Cheng, Congqian, and Min, Xiaohua
- Subjects
- *
HEAT resistant alloys , *CRYSTAL grain boundaries , *CREEP (Materials) , *DEFORMATIONS (Mechanics) , *PRECIPITATION (Chemistry) , *MECHANICAL stress analysis - Abstract
This study investigated the features of grain boundary regions in a Ni-based superalloy which underwent creep deformation. Large grain boundary zones were denuded in fine γʹ precipitates but contained coarsened microscale γʹ rods. The coarsening direction of these rods was along the <110> of the γ matrix and γʹ precipitates. The orientation of the grain boundary zone was the same as that of the adjacent grain behind the migrating boundary. This result indicated that the formation of these zones was accompanied by the migration of the grain boundary. Then, numerous slip features were observed through detailed local disorientation analysis. It is proposed that the driving force for the grain boundary migration was the local stress induced by the dislocation creep. The dissolution–reprecipitation of the precipitates at the boundary migration front resulted in the directional coarsening of the γʹ rods. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
32. Microstructure and high-temperature properties of NiAlV sheet prepared by magnetron-sputtering and foil-reaction.
- Author
-
Wang, Bao, Wang, Dongjun, Zhao, Jie, Wang, Shuai, Ning, Hanwei, Qiu, Gaosong, and Liu, Gang
- Subjects
- *
MICROSTRUCTURE , *MAGNETRON sputtering , *MICROALLOYING , *TENSILE strength , *HIGH temperatures , *ALLOYS - Abstract
[Display omitted] • NiAlV sheet was prepared by magnetron-sputtering and foil-reaction process. • Solid-liquid reaction is applied without pressure to accelerate the process. • The tensile strength of NiAl-1.01V alloy was 128.9 % higher than pure NiAl at 1000 °C. To prepare NiAl sheets with improved high-temperature strength, the V layers with different thicknesses were deposited on the single-side of Ni foils by magnetron sputtering and then the hot-pressing of laminated Ni(V)/Al foils were carried out. A NiAlV sheet consisting of V precipitates and NiAl matrix was successfully prepared using this reaction technique of laminated foils. The NiAlV alloy prepared by microalloying method can obtain better mechanical properties (166.4 MPa) and retain considerable fracture strain (54.5 %) at high temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
33. Fabrication and joining of NiAl and TiAl intermetallics by additive sintering.
- Author
-
Ning, Hanwei, Wang, Dongjun, Zhao, Jie, Wang, Bao, and Liu, Gang
- Subjects
- *
SINTERING , *ADDITIVES , *HIGH temperatures , *MICROSTRUCTURE - Abstract
To manufacture hard-to-deform intermetallics and their components at high temperatures and for a short-time, a novel additive sintering method based on solid-state powder densification is proposed, which aims to achieve the fabrication and joining of intermetallics. In this study, the sintering and joining of NiAl/NiAl and NiAl/TiAl alloys were conducted using this method. The results show that good bonding was achieved between similar intermetallics of NiAl/NiAl. Nevertheless, due to the formation of brittle phases, defects were observed in the bonding interface of the NiAl/TiAl alloy. An interlayer of V was employed to optimize the microstructure of the interface, which can prevent the formation of the brittle phase and improve the property of the interface. • A additive sintering method is proposed to manufacture dissimilar-material component. • The method can achieve fabrication and joining of dissimilar material simultaneously. • V foil as interlayer eliminates brittle IMCs at the joining interface of NiAl/TiAl. • The NiAl/V/TiAl sample shows significantly improved interfacial property. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Study of the microstructure evolution of alloy structural steel and inhomogeneity effect of the microscale pulsed currents during current-assisted plane strain compressions by modeling a novel cellular automata method.
- Author
-
Chen, Can, Xia, Qinxiang, Zhou, Haoyang, Zhao, Jie, Qin, Yi, and Xiao, Gangfeng
- Subjects
- *
CELLULAR automata , *GRAIN refinement , *MODEL airplanes , *MICROSTRUCTURE , *CURRENT distribution , *STRUCTURAL steel - Abstract
The current-assisted forming process is considered to be a novel process that utilizes the electroplasticity effect to reduce the deformation resistance of difficult-to-deform metals and to refine the grain size while improving the mechanical properties of the part. However, the lack of understanding of the mechanisms by which pulsed current affects grain refinement still makes it difficult to experimentally develop analytical or empirical models of the relationship between grain size, pulse current parameters, and deformation amount. It will seriously hinder the further development and application of the current-assisted forming process. To reveal the mechanism of grain refinement coupling with electroplasticity, a series of Electron Back Scattering Diffraction observation tests were carried out after current-assisted plane strain compressions. The results show that the grain orientation spread value of the pulse current condition is lower than that of the non-current condition, while the refined grain area percentage is higher than that of the non-current condition. Based on the microstructure observation results, a cellular automata model for grain refinement is proposed. This consists of a dislocation density evolution, sub-grains generation, grain fragmentation, and a grain orientation rotation algorithm. To study the electroplasticity of the grain refinement process, the cellular automata model is also embedded with a finite difference numerical algorithm for solving the microscopic current density distribution of the model. The cellular automata model simulation results show that the error of grain size accuracy of this cellular automata model under non-current and pulse current conditions is 10.48% and 8.55%, respectively. It shows that the model can accurately characterize the grain refinement behavior of the current-assisted plane strain compression. The simulation results reveal the deep mechanism of pulsed current promotion on grain refinement, i.e., an inhomogeneous microstructure leads to uneven distribution of pulse current density. The inhomogeneous current distribution will further increase the grain refinement rate in the coarse-grained regions, thus increasing the proportion of the refined grain regions in the microstructure and leading to a relatively more homogeneous microstructure under pulse current conditions. The cellular automata model accurately reveals the mechanism of electroplasticity on the grain refinement. The model will serve as a crucial theoretical reference in designing current-assisted forming process routes to ensure excellent microstructure and properties in manufactured parts. It will enhance the widespread utilization of current-assisted forming process. [Display omitted] • The acceleration effect of pulse current on grain refinement was verified by the CAPSC tests. • There is a positive correlation between the intensity of the electroplastic effect and the degree of grain refinement. • An innovative cellular automaton model for grain refinement was constructed using the grain fragmentation theory. • The model introduces a pulsed current accelerated grain orientation rotation mechanism to couple the electroplasticity. • The inhomogeneous current density distribution will promote the production of a more homogeneous microstructure. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
35. Preparation of high-performance NiAlV composite sheets with novel layered microstructure.
- Author
-
Wang, Bao, Wang, Dongjun, Zhao, Jie, Wang, Shuai, Ning, Hanwei, and Liu, Gang
- Subjects
- *
TENSILE strength , *HYPEREUTECTIC alloys , *SOLUTION strengthening , *MICROSTRUCTURE - Abstract
For fabricating NiAl thin-walled component and improving its high-temperature strength, a novel layered NiAlV composite sheet/cone consisting of NiAl(V) layer, NiAl–V hypereutectic layer and V (NiAl) layer have been successfully prepared using forming-reaction of laminated Ni/Al/V foils. Compared with pure NiAl, the ultimate tensile strength (UTS) of the NiAlV composite at 1000 °C is increased by 177%, which is mainly attributed to the solution strengthening and precipitation strengthening of V element. The obtained results provide a new approach for synergetic controlling shape and property of NiAl-based thin-walled component. • A forming-reaction method was proposed for fabricating closed cross-section thin-walled NiAl-based components. • Novel NiAlV composite sheet/cone consisting of different layer morphologies were successfully prepared. • The ultimate tensile strength of NiAlV composite was 201.6 MPa at 1000 °C (177% higher than pure NiAl). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. Numerical Analysis of Soil Settlement Prediction and Its Application In Large-Scale Marine Reclamation Artificial Island Project
- Author
-
Zhao Jie, Bao Lingyun, and Wang Guixuan
- Subjects
microstructure ,consolidation ,creep ,artificial island ,settlement ,Naval architecture. Shipbuilding. Marine engineering ,VM1-989 - Abstract
In an artificial island construction project based on the large-scale marine reclamation land, the soil settlement is a key to affect the late safe operation of the whole field. To analyze the factors of the soil settlement in a marine reclamation project, the SEM method in the soil micro-structural analysis method is used to test and study six soil samples such as the representative silt, mucky silty clay, silty clay and clay in the area. The structural characteristics that affect the soil settlement are obtained by observing the SEM charts at different depths. By combining numerical calculation method of Terzaghi’s one-dimensional and Biot’s two-dimensional consolidation theory, the one-dimensional and two-dimensional creep models are established and the numerical calculation results of two consolidation theories are compared in order to predict the maximum settlement of the soils 100 years after completion. The analysis results indicate that the micro-structural characteristics are the essential factor to affect the settlement in this area. Based on numerical analysis of one-dimensional and two-dimensional settlement, the settlement law and trend obtained by two numerical analysis method is similar. The analysis of this paper can provide reference and guidance to the project related to the marine reclamation land.
- Published
- 2017
- Full Text
- View/download PDF
37. Creep-induced microstructural evolution in a nickel-based superalloy designed for advanced ultra-supercritical boilers.
- Author
-
Xu, Qingshuang, Cao, Tieshan, Ye, Fei, Xu, Fanghong, Li, Huifang, Fang, Xudong, and Zhao, Jie
- Subjects
- *
NICKEL alloys , *HEAT resistant alloys , *CREEP (Materials) , *MICROSTRUCTURE , *FOCUSED ion beams , *ALLOY testing - Abstract
Long-term microstructural stability is a major concern for candidate materials used in advanced ultra-supercritical (A-USC) power plants. In the present work, precipitation behavior of a nickel based superalloy designed for A-USC boilers, with a base composition of Ni-25Cr-20Co, was investigated during long-term thermal exposure under different stresses at 1043 K. The results showed that the coarsening of γ′ precipitates in the grain interior had occurred during thermal exposure in the presence and absence of stress. The microstructure around grain boundary was altered remarkably under stress. The precipitate-free zones (PFZs) commonly existed near the grain boundary in the gauge sections of specimens after long-term creep. Coarsened and elongated particles in the PFZs were identified as γ′-Ni 3 (Ti, Al) precipitates by chemical composition analysis and diffraction pattern. Furthermore, the morphology and distribution of MC-type carbides have no significant changes observed due to their good stability, but discontinuous M 23 C 6 appeared under stress, due to formation of PFZs resulting in dissolution of the adjacent M 23 C 6 . Besides, the creep-rupture mechanism was discussed to explore a potential approach for improving creep properties. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
38. Glycerol-controlled synthesis of MoS2 hierarchical architectures with well-tailored subunits and enhanced electrochemical performance for lithium ion batteries.
- Author
-
Zhang, Su, Zeng, Yanwei, Wang, Zhentao, Zhao, Jie, and Dong, Guodian
- Subjects
- *
GLYCERIN , *MOLYBDENUM disulfide , *LITHIUM-ion batteries , *MICROSTRUCTURE , *ENERGY density - Abstract
MoS 2 three dimensional (3D) architectures with various subunits were synthesized using glycerol to mediate the growth of MoS 2 crystals though a CS 2 -assisted hydrothermal approach. It has been found that the thickness and lateral size of subunits can be distinctly reduced by increasing glycerol content in the mixture solvent. A stable porous MoS 2 architecture, composed of nanosheets with a tiny size, ∼3 layers and expanded interlayer distance, namely MoS 2 -15, was obtained when the volume proportion of glycerol reaches 15%. The sample MoS 2 -15 exhibits superior electrochemical performance in lithium ion storage, due to reasonable design as well as smart organization of MoS 2 subunits, featured by a capacity of 1027 mAh g −1 at 0.1 A g −1 after 100 cycles and 738 mAh g −1 at 5 A g −1 after 300 cycles, exceeding other MoS 2 nanostructured materials in this work. More importantly, the as-prepared various architectures exhibit tunable electrochemical behaviors depending on structure and morphology evolution, which truly reflects the potential to optimize the microstructure for lithium-ion host materials. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
39. Microstructural analysis of Cr35Ni45Nb heat-resistant steel after a five-year service in pyrolysis furnace.
- Author
-
Guo, Jingfeng, Cheng, Congqian, Li, Huifang, Zhao, Jie, and Min, Xiaohua
- Subjects
- *
HEAT resistant steel , *PYROLYSIS , *MICROSTRUCTURE , *CARBIDES , *CARBURIZATION - Abstract
To analyze the microstructure across thickness exposed to various environment of the pyrolysis furnace tubes, the sample of Cr35Ni45Nb heat-resistant steel from a five-year service tube was sliced into slices from inner to outer wall. Moreover, microhardness was examined to investigate the influence of the microstructure on the property of the heat-resistant steel. The results show that the primary carbides Cr 7 C 3 and NbC have transformed into chromium-rich Cr 23 C 6 and niobium-rich carbides G phase in the middle section of the aged pyrolysis furnace tube. The Cr 2 O 3 and SiO 2 layer covered the outer and inner surfaces, and the Cr-depleted zones were formed under the oxide layer of the inner and outer walls. The carbides of M 23 C 6 were transformed into M 7 C 3 type carbides in the carburization zone under the Cr-depleted zone of inner surface, while the M 7 C 3 type carbides also existed under the Cr-depleted zone of outer wall. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
40. Study on the mixed dynamic recrystallization mechanism during the globularization process of laser-welded TA15 Ti-alloy joint under hot tensile deformation.
- Author
-
Wang, Kehuan, Liu, Gang, Tao, Wang, Zhao, Jie, and Huang, Ke
- Subjects
- *
TITANIUM alloys , *TENSILE tests , *DEFORMATIONS (Mechanics) , *RECRYSTALLIZATION (Metallurgy) , *LASER welding , *MICROSTRUCTURE - Abstract
In this article, the hot deformation mechanism of a laser-welded near α TA15 Ti-alloy joint was studied by hot tensile tests conducted at temperatures ranging from 800 °C to 900 °C with strain rates ranging from 1.0 × 10 − 1 s − 1 to 1.0 × 10 − 3 s − 1 . The results show that the main hot deformation mechanism of the laser-welded TA15 Ti-alloy joint is continuous globularization, but dynamic recrystallization (DRX) plays an important role during the globularization process. The morphology of α phase exerts considerable influence on the DRX mechanism. When the lamella microstructure is dominant in the weld seam, continuous dynamic recrystallization (CDRX) is the active mechanism; whereas with the increasing fraction of equiaxed grains in the weld seam, discontinuous dynamic recrystallization (DDRX) seems to be the dominant mechanism during the tensile deformation. The globularization process can be divided into three stages based on the characteristics of the microstructure. Under such a deformation mechanism, the laser-welded TA15 Ti-alloy joint tends to have a good formability at high temperature and small strain rate. A maximum elongation of 292% was achieved at 900 °C, 0.001 s − 1 , which exhibits superplastic characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. Effects of hot rolled microstructure after twin-roll casting on microstructure, texture and magnetic properties of low silicon non-oriented electrical steel.
- Author
-
Liu, Hai-Tao, Wang, Yin-Ping, An, Ling-Zi, Wang, Zhao-Jie, Hou, Dao-Yuan, Chen, Jun-Mou, and Wang, Guo-Dong
- Subjects
- *
HOT rolling , *MICROSTRUCTURE , *TWIN roll casting , *SILICON , *TEMPERATURE effect , *ELECTROMAGNETIC induction ,MAGNETIC properties of electrical steel - Abstract
In this work, a 0.71 wt%Si+0.44 wt%Al as-cast strip was produced by novel twin-roll casting. Some as-cast samples were respectively reheated and hot rolled at different temperatures in order to obtain different microstructure prior to cold rolling and annealing. The effects of the hot rolled microstructure on microstructure, texture evolution and magnetic properties were investigated in detail. A coarse deformed microstructure with λ-fiber texture was formed after hot rolling at 850–1050 °C, finally leading to an inhomogeneous recrystallization microstructure with strong λ-fiber, Goss and extremely weak γ-fiber texture. By contrast, a fine transformed microstructure was formed after hot rolling at 1150–1250 °C, finally leading to a fine and homogeneous recrystallization microstructure with stronger α-fiber, γ-fiber and much weaker λ-fiber texture. It should be noted that both the magnetic induction and core loss non-monotonically decreased or increased according to the hot rolling temperature. The unfavorable α-fiber and γ-fiber textures in the annealed sheets were much weaker than those of the conventional products regardless of the hot rolling temperature, thus contributing to a much higher magnetic induction. However, the average grain size in the annealed sheets was much lower than those of the conventional products regardless of the hot rolling temperature, thus leading to a higher core loss except the case of 1050 °C. Hence, it is underscored that better integrated magnetic properties than those of the conventional products can be obtained by optimizing the hot rolled microstructure to produce final desirable recrystallization microstructure and texture. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
42. High-temperature anisotropic behaviors and microstructure evolution mechanisms of a near-α Ti-alloy sheet.
- Author
-
Wu, Yong, Fan, Ronglei, Chen, Minghe, Wang, Kehuan, Zhao, Jie, and Xiao, Wenchao
- Subjects
- *
MICROSTRUCTURE , *STRAIN rate , *TENSILE tests , *HOT working , *TENSILE strength , *TITANIUM alloys - Abstract
The high-temperature anisotropy and microstructure evolution mechanisms of the rolled TA32 titanium alloy sheet were studied. The hot deformation behaviors of the TA32 sheet along the rolling direction (RD), diagonal direction (DD), and transverse direction (TD) were studied by the uniaxial tensile tests in the temperature range of 700–900 °C and the strain rate range of 0.0001–0.1 s-1. The anisotropic coefficients were calculated by interrupted tensile tests. The microstructure and texture characteristics were observed by electron backscatter diffraction (EBSD) characterization. The effects of dislocation slip, texture evolution, dynamic recrystallization (DRX), and grain morphology on high-temperature anisotropy were comprehensively studied. Results show that the TD sample exhibited the largest peak strength and the DD sample displayed the highest elongation. The r -values decreased with increasing temperature and decreasing strain rate, and increased with increasing strain. The dominant dislocation slip modes of RD, DD, and TD samples were prismatic slip, the coupling of basal and prismatic slips, and pyramidal slips, respectively. The DRX mechanism of TA32 titanium alloy during hot deformation was the combined effects of DDRX (discontinuous dynamic recrystallization) and CDRX (continuous dynamic recrystallization), and DDRX could weaken the anisotropy. The grain growth and refinement caused by thermal effect and DRX led to the decrease and increase of r -value, respectively. In addition, the room-temperature tensile strength of the TD deformed sample showed the largest drop compared with the initial sheet, which can be attributed to the accumulation of damage and the increase of basal texture in the TD sample during the hot working. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
43. Effect of carburization (pyrolysis furnace tube main failure factor) on the microstructure and properties of HPNb alloy tube.
- Author
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Guo, Jingfeng, Cao, Tieshan, Cheng, Congqian, Meng, Xianming, and Zhao, Jie
- Subjects
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CARBURIZATION , *FURNACES , *MICROSTRUCTURE , *TUBES , *ALLOYS , *TENSILE strength - Abstract
• The paramagnetic structure of HPNb alloy change into ferromagnetic after carburization. • The M 23 C 6 carbides are replaced by carbon-rich M 7 C 3 carbides in carburization zone. • The carburized tube furnace tubes become brittle after carburization. • Carburization reduced the high temperature creep strength of HPNb alloy tube. The structure characteristics and mechanical properties of as-cast and carburized HPNb alloy tubes were investigated in this paper. Through magnetism test by the vibrating sample magnetometer, we find that the paramagnetic structure of as-cast HPNb alloy tubes has changed into ferromagnetic structure after carburization. Electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD) analyses show that the M 23 C 6 type carbide transformed into M 7 C 3 type carbide in carburization zone. Due to the coarser primary carbides and blocky-shaped secondary carbides after carburization, the ductility and toughness of the ethylene cracking furnace tubes are very low and become brittle. At high temperature, the tensile strength and yield strength of carburized tube are higher than those of as-cast tube, but the tensile elongation is lower. Owing to the microstructure degradation, the creep strength of HPNb alloy decreased after carburization. Hence, the carburization also could lead to the decrease of the remnant life of the pyrolysis furnace tubes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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