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Start Over Author "Bai, Peikang" Topic metals and alloys
10 results on '"Bai, Peikang"'

1. Grain refinement mechanism of Mg-3Sn-1Mn-1La alloy during accumulative hot rolling

Author

Yongfeng Shen, Ren-Guo Guan, Bai Peikang, and Zhanyong Zhao

Subjects
Materials science, Polymers and Plastics, Alloy, Nucleation, chemistry.chemical_element, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Phase (matter), Materials Chemistry, Lanthanum, Composite material, Mechanical Engineering, Metals and Alloys, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Mechanics of Materials, Ceramics and Composites, engineering, Dynamic recrystallization, Deformation bands, Grain boundary, Dislocation, 0210 nano-technology
Abstract

We elucidate the effect of lanthanum (La) on the grain refinement of Mg-3Sn-1Mn alloy during accumulative hot rolling. The lath-shaped Mg2Sn phase in the Mg-3Sn-1Mn alloy is firstly broken and spheroidized, and then the size increases and coarsens with the increase of rolling reduction, most of Mg2Sn move from grain boundary to grain and are homogeneously distributed within the matrix. However, the plate-shaped MgSnLa compound in Mg-3Sn-1Mn-1La gradually becomes fine, spheroidized, and homogeneously distributed. The grain sizes of Mg-3Sn-1Mn and Mg-3Sn-1Mn-1La alloys become fine through dynamic recrystallization (DRX), though the grain refinement of Mg-3Sn-1Mn-1La alloy is better compared to the Mg-3Sn-1Mn alloy. A large number of uniformly distributed spherical MgSnLa compounds pin the dislocations, thus increasing the dislocation density. Hence, the driving force for DRX increases and promotes the formation of deformation bands and more twins, providing the sites for DRX nucleation and growth.

Published
2021

2. AlSi10Mg alloy nanocomposites reinforced with aluminum-coated graphene: Selective laser melting, interfacial microstructure and property analysis

Author

Wenbo Du, Renguo Guan, Jianfeng Gao, Bai Peikang, Tao Ding, Zhanyong Zhao, Zhanhu Guo, Jiaoxia Zhang, Le Tan, Yanjun Li, R.D.K. Misra, and Mengyao Dong

Subjects
Materials science, Graphene, Mechanical Engineering, Alloy, Metals and Alloys, Nucleation, 02 engineering and technology, engineering.material, Island growth, 010402 general chemistry, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, 0104 chemical sciences, law.invention, Grain growth, Mechanics of Materials, law, Materials Chemistry, engineering, Grain boundary, Composite material, Selective laser melting, 0210 nano-technology
Abstract

Graphene has been successfully coated with a nano-Al layer through a novel activating treatment (i.e., organic aluminum reduction method). The nano-Al coated graphene was further processed into AlSi10Mg alloy based composites through a selective laser melting (SLM) process. During the nanocoating of Al on graphene, Al atoms deposited on the graphene through organic aluminum reduction gradually, via nucleation and growth process. There were two primary grain growth patterns: two dimensional (2D) layered growth and three dimensional (3D) island growth, until graphene was coated with Al. The Al-coated graphene was added to the AlSi10Mg alloy, refining the cell, increased the tensile strength, hardness and wear resistance of the alloy. Coating Al on the graphene improved the wetting between graphene and Al, and the addition of Al-coated graphene led to a high nucleation rate, which was responsible for refining the cell. This approach facilitated graphene homogeneous distribution in the Al alloy, the interface between graphene and Al was relatively stable, and the grapheme could pin the dislocation and grain boundary. All these attributes enabled superior mechanical properties to be obtained in the final alloy based nanocomposites.

Published
2019

3. Effects of Process Parameters of Semisolid Stirring on Microstructure of Mg–3Sn–1Mn–3SiC (wt%) Strip Processed by Rheo-rolling

Author

Zhou-Yang Zhao, Ren-Guo Guan, Jian-Hong Zhang, Zhanyong Zhao, and Bai Peikang

Subjects
Materials science, Composite number, Metallurgy, Metals and Alloys, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Industrial and Manufacturing Engineering, Grain size, Roundness (object), 0104 chemical sciences, Homogeneous, Scientific method, Ultimate tensile strength, Elongation, 0210 nano-technology
Abstract

A novel semisolid stirring and rheo-rolling process for preparing Mg–3Sn–1Mn–3SiC (wt%) composite strips was proposed, and the effects of process parameters of semisolid stirring on microstructures of Mg–3Sn–1Mn–3SiC (wt%) composite strips were investigated. The average grain size and roundness decrease, and the distribution of SiC becomes more homogeneous with the decrease in stirring temperature and the increase in the stirring speed. When the stirring time is increased, the distribution of SiC particles tends to be homogeneous, and the average grain diameter and roundness of α-Mg grain decrease. Under the following process parameters: the stirring temperature at 640 °C, the stirring speed at 1100 rpm, the stirring time at 30 min and the roll speed at 0.2 m/s, Mg–3Sn–1Mn–3SiC (wt%) strip with a cross-sectional size of 4 mm × 160 mm was prepared. The ultimate tensile strength and elongation of Mg–3Sn–1Mn–3SiC (wt%) composite strip reached 226 ± 6 MPa and (7.4 ± 0.2)%, which are obviously improved in comparison with Mg–3Sn–1Mn (wt%).

Published
2016

4. Microstructure and Mechanical Properties of TiC-Reinforced 316L Stainless Steel Composites Fabricated Using Selective Laser Melting

Author

Minjie Liang, Hu Liu, Jing Li, Bai Peikang, Haihong Liao, Pengchen Huo, Jiaoxia Zhang, Liyun Wu, Zhao Zhanyong, and Hongqiao Qu

Subjects
lcsh:TN1-997, 010302 applied physics, Equiaxed crystals, Austenite, corrosion resistance, Materials science, microstructure, Metal matrix composite, Metals and Alloys, Nucleation, 02 engineering and technology, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Indentation hardness, Corrosion, mechanical property, selective laser melting, 0103 physical sciences, TiC/316Lss composites, General Materials Science, Selective laser melting, Composite material, 0210 nano-technology, lcsh:Mining engineering. Metallurgy
Abstract

TiC/316L stainless steel (316Lss) metal matrix composite parts have been formed using selective laser melting (SLM). In this study, we have investigated the influence of the TiC mass fraction on the microstructure evolution, microhardness, friction properties, wear properties, and corrosion resistance of the TiC/316Lss composites. The results show that the microhardness increased by the addition of the TiC mass fraction. In terms of friction and wear properties, the corrosion resistance initially increased, and then decreased. Compared with the pure 316Lss (298.3 HV0.2), the microhardness of the TiC/316Lss composites, which were formed with 2 wt% TiC, was raised to 335.2 HV0.2, which was a 12.4% increase, while the average friction coefficient was 0.123. The reason for this is that the addition of TiC can effectively refine the cell size, and as the TiC content increases, the refinement effect is more obvious. During the melting process, TiC particles act as nucleation centres, hindering the growth of crystal cells, promoting the formation of the austenite phase, and forming fine equiaxed structures, which increases the strength. However, excessive TiC particles aggravate the spheroidisation during the process of SLM, leading to increased defects, as well as a decrease in density and corrosion resistance.

Published
2019

5. Effect of C/Ti ratio on self-propagating high-temperature synthesis reaction of Sn–Ti–C system for fabricating Ti2SnC ternary compounds

Author

Bai Peikang, Yuxin Li, and Bin Liu

Subjects
Materials science, Mechanical Engineering, Metallurgy, Metals and Alloys, Analytical chemistry, Intermetallic, Self-propagating high-temperature synthesis, Intergranular corrosion, Microstructure, chemistry.chemical_compound, chemistry, Mechanics of Materials, Ternary compound, Phase (matter), X-ray crystallography, Materials Chemistry, Ternary operation
Abstract

Ti 2 SnC ternary compound was successfully synthesized utilizing laser ignited self-propagating high-temperature synthesis (SHS) of Sn–Ti–C system with the different C/Ti molar ratio. When C/Ti ratio is 0.7, Ti 6 Sn 5 as the main phase appears, and a small amount of TiC is also found, most of the Ti 6 Sn 5 phases synthesized exhibit the polygon-shaped coarse appearance with an obviously sintered morphology, and the distinct transgranular and intergranular microcracks can be observed. When C/Ti ratio increases over the range from 0.8 to 1.0, the relative content of Ti 2 SnC increase and the plate-like shape Ti 2 SnC appears. Furthermore, the sintered density increases firstly and then decreases with the increasing of C/Ti ratio.

Published
2011

6. First Principle Study of TiB 2 (0001)/γ-Fe (111) Interfacial Strength and Heterogeneous Nucleation.

Author

Wang, Qin, Bai, Peikang, Zhao, Zhanyong, Kessler, Vadim, and Zergioti, Ioanna

Subjects
*HETEROGENOUS nucleation, *INTERFACE stability, *COVALENT bonds, *STAINLESS steel, *DENSITY of states
Abstract

TiB2/316L stainless steel composites were prepared by selective laser melting (SLM), and the adhesion work, interface energy and electronic structure of TiB2/γ-Fe interface in TiB2/316L stainless steel composites were investigated to explore the heterogeneous nucleation potential of γ-Fe grains on TiB2 particles using first principles. Six interface models composed of three different stacking positions and two different terminations were established. The B-terminated-top 2 site interface ("B-top 2") was the most stable because of the largest adhesion work, smallest interfacial distances, and smallest interfacial energy. The difference charge density and partial density of states indicated that a large number of strong Fe-B covalent bonds were formed near the "B-top 2" interface, which increased the stability of interface. Fracture analysis revealed that the bonding strength of the "B-top 2" interface was higher than that of the Fe matrix, and it was difficult to fracture at the interface. The interface energy at the Ti-poor position in the "B-top 2" interface model was smaller than that of the γ-Fe/Fe melt, indicating that TiB2 had strong heterogeneous nucleation potency for γ-Fe. [ABSTRACT FROM AUTHOR]

Published
2021
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7. Interfacial Stability of TiC/γ-Fe in TiC/316L Stainless Steel Composites Prepared by Selective Laser Melting: First Principles and Experiment.

Author

Bai, Peikang, Wang, Qin, Zhao, Zhanyong, Du, Wenbo, Liang, Minjie, Liao, Haihong, Li, Yuxin, Zhang, Lizheng, Han, Bing, and Li, Jing

Subjects
STAINLESS steel, METALLIC bonds, HETEROGENOUS nucleation, LASERS, MELTING, MOSSBAUER spectroscopy
Abstract

TiC/316L stainless steel composites were prepared by selective laser melting. The adhesion work, interface energy and electronic structure of the TiC/γ-Fe interfaces in TiC/316L stainless steel composites were studied to investigate the heterogeneous nucleation potential of γ-Fe grains on TiC particles by using the first principle. The degree mismatch between TiC (001) and γ-Fe (001) interface was lowest. There are four TiC (001)/γ-Fe (001) interface models with different stacking sequences (on-site and bridge-site) and different atomic arrangement sequences (C centre and Ti centre). The results show that the Fe-on-Ti centre interface had the largest work of adhesion (3.87 J/m2) and lower interfacial energy (0.04 J/m2), it was more stable, and the interfacial energy of the model was lower than that of γ-Fe/Fe melt (0.24 J/m2). Strong Fe-C covalent bonds and Fe-Ti metallic bonds were formed near the interface, which increased the interfacial strength, indicating that TiC had strong heterogeneous nucleation potency for γ-Fe. [ABSTRACT FROM AUTHOR]

Published
2020
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8. EBSD investigation on the microstructure of Ti48Al2Cr2Nb alloy hot isostatic pressing formed by Selective laser melting (SLM).

Author

Yang, Xiao, Zhao, Zhanyong, Bai, Peikang, Du, Wenbo, and Wang, Shaowei

Subjects
*ISOSTATIC pressing, *SELECTIVE laser melting, *HOT pressing, *MICROSTRUCTURE, *CRYSTAL grain boundaries, *GRAIN refinement
Abstract

• A typical duplex tissue composed of γ and γ/α2 obtained after HIP of Ti48Al2Cr2Nb. • Refinement of grains and reduction of LGBs after HIP of Ti48Al2Cr2Nb. • HIP treatment is an effective method for SLM samples' microstructure refinement. The Ti48Al2Cr2Nb sample was prepared by Selective laser melting (SLM), and the effect of hot isostatic pressing on its microstructure evolution was studied. The results show that the grains in the sample after hot isostatic pressing are significantly refined. The γ phase has a pinning effect, which will hinder the growth of grains, a large number of dislocations accumulate, hinder the growth of grain boundaries. The proportion of low-angle grain boundaries in the sample after hot isostatic pressing is less than that of the SLM sample. This is because some of the low-angle grain boundaries absorb dislocations during the hot isostatic pressing process, dynamic recrystallization occurs, gradually transformed into a high-angle grain boundary. [ABSTRACT FROM AUTHOR]

Published
2022
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9. Effect of in situ synthesis TiC on the microstructure of graphene/Ti6Al4V composite fabricated by selective laser melting.

Author

Wang, Shaowei, Zhao, Zhanyong, Bai, Peikang, Du, Wenbo, and Li, Liang

Subjects
*SELECTIVE laser melting, *TITANIUM carbide, *GRAPHENE synthesis, *MICROSTRUCTURE, *ZONE melting
Abstract

• More TiC is formed in the overlap zone of molten pool, which leads to grain refinement. • Graphene plays the role of heterogeneous nucleation and refines the internal structure of the composite. • A semi-coherent interface is formed between TiC and α-Ti, resulting in a strong interface bond. The graphene/Ti6Al4V composite was prepared by selective laser melting, and the effect of the addition of graphene on the microstructure of the composite was studied. The in situ synthesis of graphene and Ti6Al4V occurred, and the TiC was formed. Compared with other areas of the molten pool in the composite material, the grain of the overlap zone becomes smaller and a large number of basket-weave structures are formed and more TiC in the remelting zone than the melting zone. The addition of graphene plays a role in heterogeneous nucleation, which makes the internal structure of the composite finer than pure Ti6Al4V. The formation of the semi-coherent interface between TiC and α-Ti leads to strong interface bonding. [ABSTRACT FROM AUTHOR]

Published
2021
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10. In-situ synthesis of TiC/graphene/Ti6Al4V composite coating by laser cladding.

Author

Zhang, Lizheng, Zhao, Zhanyong, Bai, Peikang, Du, Wenbo, Li, Yuxin, Yang, Xiao, and Wang, Qin

Subjects
*METAL cladding, *COMPOSITE coating, *TITANIUM carbide, *GRAPHENE synthesis, *EUTECTIC reactions, *LASERS
Abstract

• The graphene reacted with Ti, and the TiC phase precipitated during laser cladding. • The formation mechanism of TiC phase has been revealed. • The interface of graphene/Ti6Al4V composite coating is well bonded by in-situ reactive. Graphene reinforced Ti6Al4V composite coating was prepared by laser cladding, and the microstructure of the composite coating was studied. The results show that in-situ synthesis between graphene and Ti occurred during the laser cladding process, and the feathery TiC was formed. The TiC is homogeneously distributed between α′ acicular martensite. When the carbon content is 0.5%, it is the hypoeutectic composition. During the solidification process, the β-Ti was formed firstly. With further cooling of the alloy, the eutectic reaction occurred in the remaining liquid phase, and the β-Ti and TiC were formed. Then β-Ti was transformed to α′ acicular martensite. There are still some graphene in the graphene/Ti6Al4V composite coating, which is well combined with Ti6Al4V matrix. [ABSTRACT FROM AUTHOR]

Published
2020
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