为了提高金刚石-铜合金复合材料的界面粘结强度,本文用差热分析(DTA)、X 射线衍射分析、SEM 观察及磨削试验研究了金刚石表面的 Ti 镀层对金刚石-铜基合金复合材料界面结构及性能的影响。结果表明,在600～1200℃镀Ti 层与金刚石发生界...为了提高金刚石-铜合金复合材料的界面粘结强度,本文用差热分析(DTA)、X 射线衍射分析、SEM 观察及磨削试验研究了金刚石表面的 Ti 镀层对金刚石-铜基合金复合材料界面结构及性能的影响。结果表明,在600～1200℃镀Ti 层与金刚石发生界面反应,在金刚石表面外延生成岛状 TiC,从而实现了金刚石与铜基合金的冶金结合。镀 Ti 金刚石与铜合金的粘结强度可达8×10~7Pa。用镀 Ti金刚石制成的铜基合金磨块对花岗岩的磨削比与不镀钛金刚石相比提高30%。展开更多
本文用差热分析（DTA）,X 射线衍射分析,SEM 观察及磨削试验研究了镀 W 金刚石与铜合金结合剂界面成分、结构及结合性能。结果表明:在700～1250℃范围内,镀 W 层与金刚石发生界面反应,在金刚石表面外延生成岛状 WC 和 W<sub>2<...本文用差热分析（DTA）,X 射线衍射分析,SEM 观察及磨削试验研究了镀 W 金刚石与铜合金结合剂界面成分、结构及结合性能。结果表明:在700～1250℃范围内,镀 W 层与金刚石发生界面反应,在金刚石表面外延生成岛状 WC 和 W<sub>2</sub>C 从而实现了金刚石与 W 镀层间的冶金结合,即金刚石表面金属化。镀 W 金刚石与铜合金的粘结强度可达4×10<sup>7</sup>Pa。用镀钨金刚石制成的磨块磨削比、出刃高度得到提高,金刚石的脱落率大幅度下降。展开更多
Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different s...Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different samples was observed,and the thermal conductivity of samples was measured by laser flash method.The optimal process parameters for preparing diamond/copper composites with high thermal conductivity were investigated.The results indicated that plating tungsten on diamond could modify the interface bonding.When the diamond was plated for 60 min,the coating appeared intact,uniform and flat,and the thermal conductivity of the sample could reach as high as 486 W/(m·K).The integrity and uniformity were more important than thickness for the coating.When the tungsten-plated diamond was further annealed,the metallurgical bonding between the coating and the diamond was enhanced,and the thermal conductivity rose to 559 W/(m·K).展开更多
Diamond particle dispersed copper (Cu) matrix composites were fabricated from the powder mixture composed of diamond, pure-Cu and boron (B) by spark plasma sintering (SPS). The composites were consolidated at 1173 K f...Diamond particle dispersed copper (Cu) matrix composites were fabricated from the powder mixture composed of diamond, pure-Cu and boron (B) by spark plasma sintering (SPS). The composites were consolidated at 1173 K for 600 s by SPS. The reaction between the diamond particle and the Cu matrix in the composite was not confirmed by SEM observation and X-ray diffraction (XRD) analysis. The relative packing density of the Cu/diamond composites increased with B addition and attained 93.2% - 95.8% at the B content range between 1.8 vol.% and 13.8 vol.%. The thermal conductivity of the diamond-dispersed Cu composite drastically increased with B addition and reached the maximum value of 689 W/mK at 7.2 vol% B. Numerous transgranular fractures of diamond particles were observed on bending fracture surfaces of Cu-B/diamond composites. This indicates strong bonding between the diamond particle and the Cu matrix in the composite. The coefficient of thermal expansion of the composite falls in the upper line of Kerner’s model.展开更多
Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient...Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient of thermal expansion （CTE） of 7.72 × 10-6 K-1 （25-100℃）, which are achieved by modifying the copper matrix with adding 0.3 wt.% of boron to get a good thermal contact between the matrix and the diamond particles. By adopting a series of postmachining techniques the composites were made into near-net-shape parts, and an electroless silver coating was also successfully plated on the composites. Finally, their potential applications in the thermal management of fight emitting diodes （LED） were illustrated via prototype examples.展开更多
Deformation behavior at grain levels greatly affects the machining characteristics of crystalline materials.In the present work,we investigate the influence of material anisotropy on ultra-precision diamond cutting of...Deformation behavior at grain levels greatly affects the machining characteristics of crystalline materials.In the present work,we investigate the influence of material anisotropy on ultra-precision diamond cutting of single crystalline and polycrystalline copper by experiments and crystal plasticity finite element simulations.Specifically,diamond turning and in situ SEM orthogonal cutting experiments are carried out to provide direct experimental evidence of the material anisotropy-dependent cutting results in terms of machined surface morphology and chip profile.Corresponding numerical simulations with the analysis of built stress further validate experimental results and reveal the mechanisms governing the material anisotropy influence.The above findings provide insight into the fabrication of ultra-smooth surfaces of polycrystalline metals by ultraprecision diamond turning.展开更多
文摘为了提高金刚石-铜合金复合材料的界面粘结强度,本文用差热分析(DTA)、X 射线衍射分析、SEM 观察及磨削试验研究了金刚石表面的 Ti 镀层对金刚石-铜基合金复合材料界面结构及性能的影响。结果表明,在600～1200℃镀Ti 层与金刚石发生界面反应,在金刚石表面外延生成岛状 TiC,从而实现了金刚石与铜基合金的冶金结合。镀 Ti 金刚石与铜合金的粘结强度可达8×10~7Pa。用镀 Ti金刚石制成的铜基合金磨块对花岗岩的磨削比与不镀钛金刚石相比提高30%。
文摘本文用差热分析（DTA）,X 射线衍射分析,SEM 观察及磨削试验研究了镀 W 金刚石与铜合金结合剂界面成分、结构及结合性能。结果表明:在700～1250℃范围内,镀 W 层与金刚石发生界面反应,在金刚石表面外延生成岛状 WC 和 W<sub>2</sub>C 从而实现了金刚石与 W 镀层间的冶金结合,即金刚石表面金属化。镀 W 金刚石与铜合金的粘结强度可达4×10<sup>7</sup>Pa。用镀钨金刚石制成的磨块磨削比、出刃高度得到提高,金刚石的脱落率大幅度下降。
基金supported by the National Natural Science Foundation of China(No.11802125)。
文摘Tungsten was plated on the surface of diamond by using thermal diffusion method.Different process parameters were employed to prepare the composites with tungsten,diamond and copper.The micro morphology of different samples was observed,and the thermal conductivity of samples was measured by laser flash method.The optimal process parameters for preparing diamond/copper composites with high thermal conductivity were investigated.The results indicated that plating tungsten on diamond could modify the interface bonding.When the diamond was plated for 60 min,the coating appeared intact,uniform and flat,and the thermal conductivity of the sample could reach as high as 486 W/(m·K).The integrity and uniformity were more important than thickness for the coating.When the tungsten-plated diamond was further annealed,the metallurgical bonding between the coating and the diamond was enhanced,and the thermal conductivity rose to 559 W/(m·K).
文摘Diamond particle dispersed copper (Cu) matrix composites were fabricated from the powder mixture composed of diamond, pure-Cu and boron (B) by spark plasma sintering (SPS). The composites were consolidated at 1173 K for 600 s by SPS. The reaction between the diamond particle and the Cu matrix in the composite was not confirmed by SEM observation and X-ray diffraction (XRD) analysis. The relative packing density of the Cu/diamond composites increased with B addition and attained 93.2% - 95.8% at the B content range between 1.8 vol.% and 13.8 vol.%. The thermal conductivity of the diamond-dispersed Cu composite drastically increased with B addition and reached the maximum value of 689 W/mK at 7.2 vol% B. Numerous transgranular fractures of diamond particles were observed on bending fracture surfaces of Cu-B/diamond composites. This indicates strong bonding between the diamond particle and the Cu matrix in the composite. The coefficient of thermal expansion of the composite falls in the upper line of Kerner’s model.
基金supported by the National Natural Science Foundation of China (No. 50971020)the National High-Tech Research and Development Program of China (No. 2008AA03Z505)
文摘Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient of thermal expansion （CTE） of 7.72 × 10-6 K-1 （25-100℃）, which are achieved by modifying the copper matrix with adding 0.3 wt.% of boron to get a good thermal contact between the matrix and the diamond particles. By adopting a series of postmachining techniques the composites were made into near-net-shape parts, and an electroless silver coating was also successfully plated on the composites. Finally, their potential applications in the thermal management of fight emitting diodes （LED） were illustrated via prototype examples.
基金The authors greatly acknowledge support from the Science Challenge Project(Nos.TZ2018006-0201-02 and TZ2018006-0205-02)the Fundamental Research Funds for the Central Universities.
文摘Deformation behavior at grain levels greatly affects the machining characteristics of crystalline materials.In the present work,we investigate the influence of material anisotropy on ultra-precision diamond cutting of single crystalline and polycrystalline copper by experiments and crystal plasticity finite element simulations.Specifically,diamond turning and in situ SEM orthogonal cutting experiments are carried out to provide direct experimental evidence of the material anisotropy-dependent cutting results in terms of machined surface morphology and chip profile.Corresponding numerical simulations with the analysis of built stress further validate experimental results and reveal the mechanisms governing the material anisotropy influence.The above findings provide insight into the fabrication of ultra-smooth surfaces of polycrystalline metals by ultraprecision diamond turning.
