21 results on '"An, Zhiguo"'
Search Results
2. Effect of Sintering Temperature on the Microstructure and Properties of High-Strength and Highly Conductive 5 wt.% ZrB2/Cu Composite
- Author
-
Peng, Zhang, Chenchen, Wang, Shengfeng, Zhou, Baisong, Guo, Zhiguo, Zhang, Zhentao, Yu, and Wei, Li
- Published
- 2023
- Full Text
- View/download PDF
3. Effect of Al on microstructure and mechanical properties of as-cast Mg-8Gd-4Y-1Zn alloy
- Author
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Zhou, Yongxin, Li, Qian, Xing, Zhiguo, Zhou, Renze, Huang, Zhenhua, Huang, Yanfei, and Guo, Weiling
- Published
- 2020
- Full Text
- View/download PDF
4. Formation and impact of functionally graded buffer layers between martensitic stainless steel and wrought steel substrate by laser metal deposition
- Author
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Zhiguo Wang, Jibin Zhao, Yuhui Zhao, Zhihao Zhang, Hongyu Zhang, and Zhenfeng He
- Subjects
Laser metal deposition ,Metals and alloys ,Microstructure ,Functionally graded structure ,Mechanical properties ,Buffer layer ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
In this study, the martensitic stainless-steel powder had been successfully deposited on the surfaces of 1045 wrought steel substrates using five types of laser metal deposition strategies. The results showed that a thin buffer layer can be naturally generated in-between the deposition layer and substrate owning to the dilution effect, producing functionally graded structures consisted of martensite dendrite matrices and intermetallic phases (e.g., M23(C, B)6). Unfortunately, the poor deformation characteristic of natural buffer layers can exacerbate the risk of cracking, leading to an incompatibility between martensitic stainless steel and forming steel. A thick artificial buffer layer was then designed by addition of Inconel 625 powder. Because of the formation of graded austenite phase in the artificial buffer layer, the yield strength of specimen was enhanced significantly. Hence, our study can be used for manufacture of reliable moulds with high surface hardness and structural strength and may be helpful in further developing hybrid forming strategy in the field of mould manufacture. When subjected to stress impact during mould filling, the artificial buffer layer with functionally graded properties would have a perfect capability to bear the deformation as the load increased, dramatically improving the reliability and functionality of moulds.
- Published
- 2021
- Full Text
- View/download PDF
5. Numerical Simulation and Experimental Investigation on Electron Beam Welding of Spray-Formed 7055 Aluminum Alloy
- Author
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Shaogang Wang, Zheng Wang, Chengcong Zhang, and Zhiguo Wang
- Subjects
7055 aluminum alloy ,electron beam welding ,numerical simulation ,microstructure ,mechanical properties ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The spray-formed 7055 aluminum alloy is welded by electron beam welding. Combined with the numerical simulation of a welding temperature field, the effect of different welding procedures on the microstructure and mechanical properties of welded joints is investigated in this study. Results show that the joints with good properties can be obtained under proper welding procedures. The microstructure analysis demonstrates that the fusion zone mainly consists of equiaxed grains, while a fine equiaxed grain zone is formed near the fusion line. There are mainly α(Al), MgZn2, Al2CuMg, and Mg32(Al,Zn)49 phases in the weld metal. The morphology of the weld can be improved by modification welding after the first bead welding, which is also advantageous to the mechanical properties of a welded joint. In the as-welded condition, compared with that of the base metal, the hardness of the weld zone decreased to a certain extent. The maximum tensile strength of a welded joint reaches 371.7 MPa. There are many dimples on the tensile fracture surface of a welded joint, and it dominantly presents the characteristic of ductile fracture. The simulated molten pool is consistent with the experimental weld morphology, and the reliability and accuracy of the simulation analysis are verified.
- Published
- 2020
- Full Text
- View/download PDF
6. Effect of Sintering Temperature on the Microstructure and Properties of High-Strength and Highly Conductive 5 wt.% ZrB2/Cu Composite.
- Author
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Peng, Zhang, Chenchen, Wang, Shengfeng, Zhou, Baisong, Guo, Zhiguo, Zhang, Zhentao, Yu, and Wei, Li
- Subjects
ELECTRIC charge ,TEMPERATURE effect ,MICROSTRUCTURE ,THERMAL conductivity ,COPPER ,NANOINDENTATION - Abstract
Cu matrix composites have received increased attention in a wide industrial area because of their excellent mechanical properties and good electrical and thermal conductivity. However, the addition of general ceramic reinforcements often leads to a marked reduction in electrical conductivity for Cu matrix composites. In this study, the ZrB
2 -reinforced Cu composites have been developed to overcome this drawback since these metal borides possess relatively high electrical conductivity. The 5 wt.% ZrB2 /Cu composites were prepared using hot-pressed sintering techniques at varying temperatures from 760 to 920°C. The influence of sintering temperature on the microstructure, relative density, and mechanical and electrical properties was examined. The results of the SEM observation show that ZrB2 particles are seamlessly integrated into the Cu matrix for all ZrB2 /Cu composites. The average grain size of the Cu matrix increases from 360 to 980 nm with the increase of the sintering temperature. The increase in sintering temperature also leads to the surface porosity decrease from 1.4 to 0.4%. The relative density and electric conductivity of the composites increase at the same time as the sintering temperature increases. However, microhardness increases and decreases, with a maximum value of 92 HV0.2 achieved at 840°C. The elastic modulus and nanohardness maps determined from the nanoindentation indicate that the reinforced ZrB2 particles demonstrate the highest values for elastic modulus (340–500 GPa) and nanohardness (30–48 GPa). At the same time, the Cu matrix possesses a modulus of 100–200 GPa and nanohardness of about 10 GPa. TEM observation confirmed that the sintering temperature exhibits little influence on the interface reaction between ZrB2 and Cu. Both sharp interface and interface with amorphous transition layer are observed. The variation of microhardness is mainly due to the strengthening of grain refinement and to the mismatch of the thermal expansion coefficients. The above results can provide further insights into the deeper understanding of the role of sintering temperature during hot-pressed sintering. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
7. Effect of Mo Concentration on the Microstructure Evolution and Properties of High Boron Cast Steel
- Author
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Kong Lingnan, Feihong Zhang, Chen Zhiguo, Miao Sen, Hongbin Yu, and Xiang Wei
- Subjects
Materials science ,chemistry.chemical_element ,02 engineering and technology ,mechanical properties ,wear resistance ,lcsh:Technology ,01 natural sciences ,Article ,molybdenum ,0103 physical sciences ,Adhesive wear ,General Materials Science ,Composite material ,lcsh:Microscopy ,Boron ,high boron cast steel ,lcsh:QC120-168.85 ,010302 applied physics ,lcsh:QH201-278.5 ,lcsh:T ,Abrasive ,Tribology ,021001 nanoscience & nanotechnology ,Microstructure ,Solid solution strengthening ,chemistry ,borides ,lcsh:TA1-2040 ,Molybdenum ,lcsh:Descriptive and experimental mechanics ,Grain boundary ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,lcsh:TK1-9971 - Abstract
The microstructure evolution, mechanical properties, and tribological properties of high boron cast steel (HBCS) with various Mo concentrations are investigated. The results indicate that Mo addition can significantly modify the microstructure and enhance the comprehensive properties. With the increase of Mo concentration, borides change from the original fish-bone Fe-rich and Cr-rich M2B to dendritic Fe-rich M2B, blocky and cluster-like Cr-rich M2B, and grainy Mo-rich M2B. The hardness of HBCS increases gradually with the increase of Mo content due to the solid solution strengthening and the refinement of M2B. It can be found that all the samples exhibit quasi-cleavage, but the impact toughness increases firstly and reaches the maximum value when the concentration of Mo is 2.10 wt.%, which is the result of the dispersive distribution of M2B rather than the original fish-bone M2B. Subsequently, the impact toughness begins to decrease as the concentration of Mo further increases because of the extensive formation of grainy Mo-rich M2B at the grain boundary. Meanwhile, the wear results reveal that the average friction coefficient and wear ratio decrease with the increase of Mo content, and the wear mechanism changes from abrasive wear and adhesive wear to abrasive wear when the concentration of Mo exceeds 2.10 wt.%.
- Published
- 2020
- Full Text
- View/download PDF
8. Formation and impact of functionally graded buffer layers between martensitic stainless steel and wrought steel substrate by laser metal deposition
- Author
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Zhao Jibin, Wang Zhiguo, He Zhenfeng, Hongyu Zhang, Zhihao Zhang, and Yuhui Zhao
- Subjects
Materials science ,Functionally graded structure ,Mechanical properties ,02 engineering and technology ,Martensitic stainless steel ,engineering.material ,010402 general chemistry ,01 natural sciences ,Buffer (optical fiber) ,Stress (mechanics) ,lcsh:TA401-492 ,General Materials Science ,Composite material ,Microstructure ,Buffer layer ,Austenite ,Mechanical Engineering ,Metals and alloys ,021001 nanoscience & nanotechnology ,Inconel 625 ,0104 chemical sciences ,Mechanics of Materials ,Martensite ,engineering ,Laser metal deposition ,lcsh:Materials of engineering and construction. Mechanics of materials ,Deformation (engineering) ,0210 nano-technology ,Layer (electronics) - Abstract
In this study, the martensitic stainless-steel powder had been successfully deposited on the surfaces of 1045 wrought steel substrates using five types of laser metal deposition strategies. The results showed that a thin buffer layer can be naturally generated in-between the deposition layer and substrate owning to the dilution effect, producing functionally graded structures consisted of martensite dendrite matrices and intermetallic phases (e.g., M23(C, B)6). Unfortunately, the poor deformation characteristic of natural buffer layers can exacerbate the risk of cracking, leading to an incompatibility between martensitic stainless steel and forming steel. A thick artificial buffer layer was then designed by addition of Inconel 625 powder. Because of the formation of graded austenite phase in the artificial buffer layer, the yield strength of specimen was enhanced significantly. Hence, our study can be used for manufacture of reliable moulds with high surface hardness and structural strength and may be helpful in further developing hybrid forming strategy in the field of mould manufacture. When subjected to stress impact during mould filling, the artificial buffer layer with functionally graded properties would have a perfect capability to bear the deformation as the load increased, dramatically improving the reliability and functionality of moulds.
- Published
- 2021
9. Numerical Simulation and Experimental Investigation on Electron Beam Welding of Spray-Formed 7055 Aluminum Alloy
- Author
-
Zhiguo Wang, Chengcong Zhang, Zheng Wang, and Shaogang Wang
- Subjects
lcsh:TN1-997 ,Equiaxed crystals ,Materials science ,microstructure ,Alloy ,02 engineering and technology ,Welding ,mechanical properties ,engineering.material ,01 natural sciences ,law.invention ,7055 aluminum alloy ,law ,0103 physical sciences ,Ultimate tensile strength ,Electron beam welding ,General Materials Science ,Composite material ,Joint (geology) ,lcsh:Mining engineering. Metallurgy ,010302 applied physics ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Microstructure ,numerical simulation ,engineering ,Fracture (geology) ,0210 nano-technology ,electron beam welding - Abstract
The spray-formed 7055 aluminum alloy is welded by electron beam welding. Combined with the numerical simulation of a welding temperature field, the effect of different welding procedures on the microstructure and mechanical properties of welded joints is investigated in this study. Results show that the joints with good properties can be obtained under proper welding procedures. The microstructure analysis demonstrates that the fusion zone mainly consists of equiaxed grains, while a fine equiaxed grain zone is formed near the fusion line. There are mainly &alpha, (Al), MgZn2, Al2CuMg, and Mg32(Al,Zn)49 phases in the weld metal. The morphology of the weld can be improved by modification welding after the first bead welding, which is also advantageous to the mechanical properties of a welded joint. In the as-welded condition, compared with that of the base metal, the hardness of the weld zone decreased to a certain extent. The maximum tensile strength of a welded joint reaches 371.7 MPa. There are many dimples on the tensile fracture surface of a welded joint, and it dominantly presents the characteristic of ductile fracture. The simulated molten pool is consistent with the experimental weld morphology, and the reliability and accuracy of the simulation analysis are verified.
- Published
- 2020
10. Achieving High Strength and Good Ductility in As-Extruded Mg–Gd–Y–Zn Alloys by Ce Micro-Alloying
- Author
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Zhiguo An, Zhengyuan Gao, Qiuyan Huang, Hu Linsheng, Jun Li, and Jinfeng Li
- Subjects
Materials science ,alloying ,Alloy ,02 engineering and technology ,engineering.material ,mechanical properties ,01 natural sciences ,lcsh:Technology ,Article ,dynamic recrystallization ,magnesium alloys ,0103 physical sciences ,Ultimate tensile strength ,Nano ,General Materials Science ,Composite material ,Solubility ,lcsh:Microscopy ,lcsh:QC120-168.85 ,010302 applied physics ,lcsh:QH201-278.5 ,lcsh:T ,second phases ,021001 nanoscience & nanotechnology ,Microstructure ,Grain size ,lcsh:TA1-2040 ,Dynamic recrystallization ,engineering ,Extrusion ,lcsh:Descriptive and experimental mechanics ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,0210 nano-technology ,lcsh:Engineering (General). Civil engineering (General) ,lcsh:TK1-9971 - Abstract
In this study, the effect of Ce additions on microstructure evolution of Mg-7Gd-3.5Y-0.3Zn (wt %) alloys during the casting, homogenization, aging and extrusion processing are investigated, and novel mechanical properties are also obtained. The results show that Ce addition promotes the formation of long period stacking ordered (LPSO) phases in the as-cast Mg-Gd-Y-Zn-Ce alloys. A high content of Ce addition would reduce the maximum solubility of Gd and Y in the Mg matrix, which leads to the higher density of Mg12Ce phases in the as-homogenized alloys. The major second phases observed in the as-extruded alloys are micron-sized bulk LPSO phases, nano-sized stripe LPSO phases, and broken Mg12Ce and Mg5RE phases. Recrystallized grain size of the as-extruded 0.2Ce, 0.5Ce and 1.0Ce alloys can be refined to ~4.3 μm, ~1.0 μm and ~8.4 μm, respectively, which is caused by the synthesized effect of both micron phases and nano phases. The strength and ductility of as-extruded samples firstly increase and then decrease with increasing Ce content. As-extruded 0.5Ce alloy exhibits optimal mechanical properties, with ultimate strength of 365 MPa and ductility of ~15% simultaneously.
- Published
- 2018
11. Martensitic transformations and the shape memory effect in Ti-Zr-Nb-Al high-temperature shape memory alloys.
- Author
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Zhang, Fei, Yu, Zhiguo, Xiong, Chengyang, Qu, Wentao, Yuan, Bifei, Wang, Zhenguo, and Li, Yan
- Subjects
- *
MARTENSITIC transformations , *SHAPE memory alloys , *HIGH temperature chemistry , *X-ray diffraction , *MECHANICAL behavior of materials - Abstract
The microstructures, phase transformations, mechanical properties and shape memory effect of Ti-20Zr-10Nb-xAl (x=1, 2, 3, 4 at%) alloys were investigated. The X-ray diffraction results show that the alloys are composed of a single martensitic α″-phase and that the corresponding unit cell volume decreases with increasing Al content. The reverse martensitic transformation start temperature ( A s ) of the Ti-20Zr-10Nb-Al alloy is 534 K and decreases with increasing Al content. The addition of Al results in solid solution strengthening and grain refinement strengthening, thus improving the mechanical properties and the shape memory effect of the Ti-20Zr-10 Nb-xAl alloys. The Ti-20Zr-10Nb-3Al alloy shows the greatest shape memory strain (3.2%) and the largest tensile strain (17.6%) as well as a very high tensile strength (886 MPa). [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
12. Microstructure Evaluation and Mechanical Properties of Low Alloy Cryogenic Steel Processed by Normalizing Treatment.
- Author
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Liu, Zili, Liu, Xiqin, Hou, Zhiguo, Zhou, Shuangshuang, and Tian, Qingchao
- Subjects
CRYSTAL grain boundaries ,FERRITES ,MICROSTRUCTURE ,GRAIN size ,SHEAR (Mechanics) - Abstract
Effects of the normalizing treatment on microstructural evolution, mechanical properties, and impact fracture behavior of 20MnV low alloy cryogenic as-rolled steel were evaluated. The results indicate that grain boundary carbide and acicular ferrite of the as-rolled steel were eliminated and a large amount of nanoscale VC precipitates were observed after 860 °C normalizing treatment. The as-normalized steel had lower strength, higher elongation, and impact absorbed energy than as-rolled steel. The optimal comprehensive mechanical property, especially the superior cryogenic toughness with impact absorbed energy values at −20 and −50 °C were 62 and 40 J, respectively, was obtained at 860 °C. The as-rolled steel contained shearing crack and necking crack simultaneously, while 860 °C as-normalized steel only contained deflecting necking crack, indicating the significant improvement of the toughness. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
13. Formation and impact of functionally graded buffer layers between martensitic stainless steel and wrought steel substrate by laser metal deposition.
- Author
-
Wang, Zhiguo, Zhao, Jibin, Zhao, Yuhui, Zhang, Zhihao, Zhang, Hongyu, and He, Zhenfeng
- Subjects
- *
LASER deposition , *MARTENSITIC stainless steel , *BUFFER layers , *STEEL , *IRON-manganese alloys , *STAINLESS steel - Abstract
In this study, the martensitic stainless-steel powder had been successfully deposited on the surfaces of 1045 wrought steel substrates using five types of laser metal deposition strategies. The results showed that a thin buffer layer can be naturally generated in-between the deposition layer and substrate owning to the dilution effect, producing functionally graded structures consisted of martensite dendrite matrices and intermetallic phases (e.g., M 23 (C, B) 6). Unfortunately, the poor deformation characteristic of natural buffer layers can exacerbate the risk of cracking, leading to an incompatibility between martensitic stainless steel and forming steel. A thick artificial buffer layer was then designed by addition of Inconel 625 powder. Because of the formation of graded austenite phase in the artificial buffer layer, the yield strength of specimen was enhanced significantly. Hence, our study can be used for manufacture of reliable moulds with high surface hardness and structural strength and may be helpful in further developing hybrid forming strategy in the field of mould manufacture. When subjected to stress impact during mould filling, the artificial buffer layer with functionally graded properties would have a perfect capability to bear the deformation as the load increased, dramatically improving the reliability and functionality of moulds. Unlabelled Image • The buffer layers was formed due to the dilution effect. • The artificial buffer layer had perfect functionally graded properties. • A hybrid mould with artificial buffer layer was fabricated by LMD. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. Numerical Simulation and Experimental Investigation on Electron Beam Welding of Spray-Formed 7055 Aluminum Alloy.
- Author
-
Wang, Shaogang, Wang, Zheng, Zhang, Chengcong, and Wang, Zhiguo
- Subjects
ELECTRON beam welding ,ELECTRON beams ,ALUMINUM alloy welding ,ALUMINUM alloys ,COMPUTER simulation ,WELDED joints ,DUCTILE fractures - Abstract
The spray-formed 7055 aluminum alloy is welded by electron beam welding. Combined with the numerical simulation of a welding temperature field, the effect of different welding procedures on the microstructure and mechanical properties of welded joints is investigated in this study. Results show that the joints with good properties can be obtained under proper welding procedures. The microstructure analysis demonstrates that the fusion zone mainly consists of equiaxed grains, while a fine equiaxed grain zone is formed near the fusion line. There are mainly α(Al), MgZn
2 , Al2 CuMg, and Mg32 (Al,Zn)49 phases in the weld metal. The morphology of the weld can be improved by modification welding after the first bead welding, which is also advantageous to the mechanical properties of a welded joint. In the as-welded condition, compared with that of the base metal, the hardness of the weld zone decreased to a certain extent. The maximum tensile strength of a welded joint reaches 371.7 MPa. There are many dimples on the tensile fracture surface of a welded joint, and it dominantly presents the characteristic of ductile fracture. The simulated molten pool is consistent with the experimental weld morphology, and the reliability and accuracy of the simulation analysis are verified. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
15. Effect of Mo Concentration on the Microstructure Evolution and Properties of High Boron Cast Steel.
- Author
-
Chen, Zhiguo, Miao, Sen, Kong, Lingnan, Wei, Xiang, Zhang, Feihong, and Yu, Hongbin
- Subjects
- *
CAST steel , *FRETTING corrosion , *ADHESIVE wear , *SOLUTION strengthening , *MOLYBDENUM , *MICROSTRUCTURE , *BORON steel , *ADHESIVES - Abstract
The microstructure evolution, mechanical properties, and tribological properties of high boron cast steel (HBCS) with various Mo concentrations are investigated. The results indicate that Mo addition can significantly modify the microstructure and enhance the comprehensive properties. With the increase of Mo concentration, borides change from the original fish-bone Fe-rich and Cr-rich M2B to dendritic Fe-rich M2B, blocky and cluster-like Cr-rich M2B, and grainy Mo-rich M2B. The hardness of HBCS increases gradually with the increase of Mo content due to the solid solution strengthening and the refinement of M2B. It can be found that all the samples exhibit quasi-cleavage, but the impact toughness increases firstly and reaches the maximum value when the concentration of Mo is 2.10 wt.%, which is the result of the dispersive distribution of M2B rather than the original fish-bone M2B. Subsequently, the impact toughness begins to decrease as the concentration of Mo further increases because of the extensive formation of grainy Mo-rich M2B at the grain boundary. Meanwhile, the wear results reveal that the average friction coefficient and wear ratio decrease with the increase of Mo content, and the wear mechanism changes from abrasive wear and adhesive wear to abrasive wear when the concentration of Mo exceeds 2.10 wt.%. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
16. Microstructure and mechanical properties of the spark plasma sintered TaC/SiC composites
- Author
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Liu, Limeng, Ye, Feng, Zhang, Zhiguo, and Zhou, Yu
- Subjects
- *
TANTALUM alloys , *SILICON carbide , *COMPOSITE materials , *MICROSTRUCTURE , *MECHANICAL behavior of materials , *SINTERING , *POROSITY - Abstract
Abstract: TaC/SiC composites with 5–40vol.% 6H–SiC were fabricated by spark plasma sintering at 1800°C for 5min. Effects of SiC concentrations on the densification, microstructure, and mechanical properties of the materials were investigated. The results showed the densification process of the TaC/SiC composites was composed of six sequent stages. SiC addition was effective in eliminating the closed porosities in the final stage to yield fully dense TaC/SiC composites at 20vol.% SiC concentrations and above. TaC grain sizes decreased with SiC concentration increase. The 40vol.% SiC composition had the highest flexure strength and fracture toughness up to 703MPa and 6.8MPam1/2 due to the reinforcement of the SiC agent. The TaC/SiC composites with 20 and 40vol.% SiC showed good flexural strength at 1400°C. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
17. Effect of Cr micro-alloying on microstructure and mechanical properties of alumina whisker and graphene co-reinforced copper matrix composites.
- Author
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Shao, Zhenyi, Jiang, Xiaosong, Shu, Rui, Wu, Zixuan, Huang, Zhiguo, Deng, Hao, Qin, Qing, and Zhu, Minhao
- Subjects
- *
ALUMINUM composites , *CRYSTAL whiskers , *ALUMINA composites , *MICROALLOYING , *MICROSTRUCTURE , *INTERFACIAL bonding , *SPECIFIC gravity - Abstract
This work attempted to strengthen the interfacial strength and mechanical properties of alumina whisker and graphene co-reinforced copper matrix composites by Cr matrix micro-alloying. Cr elements are observed to: (i) aggregate to form large particles rather than disperse uniformly in Cu matrix; (ii) disperse at interfaces between Cu matrix and reinforcements. The relative density, tensile strength, shear strength and compressive strength of the Cu-Cr composites were in direct proportional to Cr micro-alloying amount from 0 to 1.5 wt%. Increased Cr micro-alloying amount, on the one hand, can strengthen interfacial bonding between Cu matrix and reinforcements and thereby enhance the load transfer efficiency at interfaces; on the other hand, can yield obvious grain refinement, and thereby achieving grain boundary strengthening as well as twin boundary strengthening, which were considered as the dominant strengthening mechanisms of Cu-Cr composites. Besides, dislocation strengthening and solid-solution strengthening were also additional strengthening mechanisms of Cu-Cr composites. [Display omitted] • Cr micro-alloying can significantly improve the mechanical properties of Cu matrix composites. • Cr micro-alloying can strengthen interfacial bonding between Cu matrix and reinforcements. • Cr micro-alloying can yield grain refinement. • The strengthening mechanisms mediated by Cr micro-alloying were analyzed in detail. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
18. Densification of tantalum carbide ceramics with 5mol.% Al, Cu, Ag and Au.
- Author
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Liu, Limeng, Zhong, Lianbing, Zhang, Baoyou, Lai, Zhonghong, Ye, Feng, Zhang, Zhiguo, and Zhou, Yu
- Subjects
- *
TANTALUM compounds , *CARBIDES , *CERAMICS , *MICROSTRUCTURE , *METALLIC films , *WETTING - Abstract
The effects of the addition of 5mol.% aluminum, copper, silver or gold on the densification, microstructures, mechanical properties and oxidation resistance in thin air of TaC ceramics were investigated. Full density and relatively high flexural strength (up to 738MPa) were observed in the case of the Au addition after spark plasma sintering at 1700°C for 5min under 30MPa pressure. Due to wetting of the TaC grains by a thin metallic film, the consolidated materials showed enhanced oxidation resistance against thin air. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
19. Microstructure and mechanical properties of the spark plasma sintered TaC/SiC composites: Effects of sintering temperatures
- Author
-
Liu, Han, Liu, Limeng, Ye, Feng, Zhang, Zhiguo, and Zhou, Yu
- Subjects
- *
MICROSTRUCTURE , *MECHANICAL properties of metals , *PLASMA gases , *SINTERING , *TANTALUM compounds , *SILICON carbide , *TEMPERATURE effect , *CRYSTAL grain boundaries , *COMPOSITE materials - Abstract
Abstract: TaC/SiC composites with 20vol.% SiC addition were densified by spark plasma sintering at 1600–1900°C for 5min under 40MPa. Effects of sintering temperatures on the densification, microstructures and mechanical properties of composites were investigated. The results showed the materials achieved >98% of theoretical density at a temperature as low as 1600°C. While the TaC grains grew slightly with the sintering temperature increasing, the SiC particles in materials decreased in size. Equiaxed to elongated grain morphology transformation was observed in the SiC phase in the 1900°C material to obtain a higher flexural strength and fracture toughness of 715MPa and 6.7MPam1/2, respectively. Lattice enlargement of the TaC phase in the 1900°C material suggested possible Si diffusion into TaC grains. Ta was also detected in SiC grains by energy dispersive spectroscopy. Glassy pockets present at multi-grain junctions explained the enhanced densification. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
20. Microstructure compatibility and its effect on the mechanical properties of the α-SiC/β-Si3N4 co-reinforced barium aluminosilicate glass ceramic matrix composites
- Author
-
Liu, Limeng, Ye, Feng, Zhou, Yu, and Zhang, Zhiguo
- Subjects
- *
MICROSTRUCTURE , *GLASS-ceramics , *SILICON carbide , *SILICON nitride , *SINTERING , *ALUMINUM silicates , *COMPOSITE materials , *MECHANICAL behavior of materials - Abstract
Monolithic α-SiC particles and in situ β-Si3N4-reinforced barium aluminosilicate (BAS) glass ceramic matrix composites with good mechanical properties were obtained by spark plasma sintering. However, attempts at the synthesis of ternary phase composites in order to maximize the reinforcing effects by co-adding α-SiC and β-Si3N4 were only partly successful. β-Si3N4 grain growth was remarkably hindered by the coexistent α-SiC, thus the resultant composite suffered a loss of reinforcement efficiency. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
- View/download PDF
21. Novel mixed α/β-SiAlONs with both elongated α and β grains
- Author
-
Ye, Feng, Liu, Limeng, Zhang, Haijiao, Zhou, Yu, and Zhang, Zhiguo
- Subjects
- *
GLASS-ceramics , *METAL crystal growth , *MICROFABRICATION , *SEMICONDUCTOR doping , *MECHANICAL behavior of materials , *MICROSTRUCTURE , *SILICON compounds - Abstract
Yb-, Y- and Dy-doped mixed α/β-SiAlON ceramics were fabricated by hot-pressing using 10wt.% BaAl2Si2O8 (BAS) glass ceramic as an additive. The results showed that BAS could effectively facilitate the anisotropic growth of both α- and β-SiAlON grains. The α-SiAlON grains as well as the β-SiAlON grains were highly elongated. The obtained mixed α/β-SiAlONs possess much better mechanical properties than those of conventional mixed α/β-SiAlONs containing equiaxed α-SiAlON grains in their microstructure. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
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