利用电解沉积技术制备出高纯度、高致密度的块状纳米 Cu 样品。该样品经室温下冷轧,延伸率可高达5100％,且冷轧过程中无加工硬化效应产生。微观结构分析表明纳米晶体 Cu 的变形机制是由晶界运动来控制而非普通粗晶体材料的位错运动机制...利用电解沉积技术制备出高纯度、高致密度的块状纳米 Cu 样品。该样品经室温下冷轧,延伸率可高达5100％,且冷轧过程中无加工硬化效应产生。微观结构分析表明纳米晶体 Cu 的变形机制是由晶界运动来控制而非普通粗晶体材料的位错运动机制。这一发现有力地证明了纳米晶体材料具有与普通多晶材料完全不同的力学行为,并为深入理解纳米材料的结构性能关系及拓展纳米材料的工业应用开辟了新路。展开更多
The micrometer-sized Cu powder produced on commercial scale was compacted under pressure of 1.0?2.0 GPa and at room temperature,and the nanocrystalline(nc) Cu with diameter of 10 mm and thickness of 8 mm, relative den...The micrometer-sized Cu powder produced on commercial scale was compacted under pressure of 1.0?2.0 GPa and at room temperature,and the nanocrystalline(nc) Cu with diameter of 10 mm and thickness of 8 mm, relative density of 99.4% of the theoretical density for pure Cu (8.96 g/cm3), and mean grain size of 34?43 nm and microstrain of 0.16%?0.19% was obtained. The compacting process was analyzed with HUANG Pei-yun equation and the microstructure and properties of nc Cu were studied by XRD, SEM, PAS, MHV2000 mircrohardness tester and Datron 1081-type electrometer. The results show that the grain size of nc Cu samples is correlated with compacting pressure, the microhardness is 1.14?1.27 GPa which is about two times larger than that of the coarse-grained polycrystalline Cu, but the relationship between microhardness and grain size do not obey Hall-Petch equation strictly. The electrical resistivity of the specimens is 5.1×10?7Ω·m, larger than the coarse-grained Cu materials by a factor of 29, the mean lifetime of positron-annihilation is (172.8±0.8) ps. The cost of the method of fabrication for big-sized nc material is much lower than that of any others. This method has the advantages such as the lowest cost, largest output and volume as well as highest density over all other methods so far.展开更多
文摘利用电解沉积技术制备出高纯度、高致密度的块状纳米 Cu 样品。该样品经室温下冷轧,延伸率可高达5100％,且冷轧过程中无加工硬化效应产生。微观结构分析表明纳米晶体 Cu 的变形机制是由晶界运动来控制而非普通粗晶体材料的位错运动机制。这一发现有力地证明了纳米晶体材料具有与普通多晶材料完全不同的力学行为,并为深入理解纳米材料的结构性能关系及拓展纳米材料的工业应用开辟了新路。
基金Sponsored by State Key Laboratory of Rare Earth Permanent Magnetic Materials(SKLREPM17OF06)National Natural Science Foundation of China(51871201)Key R&D Project of Zhejiang Provincial Department of Science and Technology(2021C01172)。
基金Project(10475069/A0506) supported by the National Natural Science Foundation of China
文摘The micrometer-sized Cu powder produced on commercial scale was compacted under pressure of 1.0?2.0 GPa and at room temperature,and the nanocrystalline(nc) Cu with diameter of 10 mm and thickness of 8 mm, relative density of 99.4% of the theoretical density for pure Cu (8.96 g/cm3), and mean grain size of 34?43 nm and microstrain of 0.16%?0.19% was obtained. The compacting process was analyzed with HUANG Pei-yun equation and the microstructure and properties of nc Cu were studied by XRD, SEM, PAS, MHV2000 mircrohardness tester and Datron 1081-type electrometer. The results show that the grain size of nc Cu samples is correlated with compacting pressure, the microhardness is 1.14?1.27 GPa which is about two times larger than that of the coarse-grained polycrystalline Cu, but the relationship between microhardness and grain size do not obey Hall-Petch equation strictly. The electrical resistivity of the specimens is 5.1×10?7Ω·m, larger than the coarse-grained Cu materials by a factor of 29, the mean lifetime of positron-annihilation is (172.8±0.8) ps. The cost of the method of fabrication for big-sized nc material is much lower than that of any others. This method has the advantages such as the lowest cost, largest output and volume as well as highest density over all other methods so far.
