Grain growth and mechanical properties of electrodeposited nanocrystalline nickel–4.4mass% phosphorus alloy
Grain growth and mechanical properties of electrodeposited nanocrystalline nickel–4.4mass% phosphorus alloy
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DOI：
10.1016/s0921-5093(03)00285-5
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发表时间：
2003-10
期刊：
影响因子：
6.4
通讯作者：
S. Kobayashi;Y. Kashikura
中科院分区：
文献类型：
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作者：
S. Kobayashi;Y. Kashikura
系统地研究了Ni-4.4mass%P合金的显微组织演变与力学性能的关系。电沉积态Ni-4.4mass%P合金由平均晶粒尺寸为37 nm的晶粒组成，织构强烈取向于（111）。磷完全在固溶体中。热处理诱导Ni 3 P相析出。快速晶粒长大只发生在热处理的初始阶段，并在所有的退火温度，甚至在温度高于873 K（0.51 Tm）的饱和。Ni相和Ni_3 P相的晶粒长大指数n分别为4.5-5.9和4.9-5.4。这些值接近于晶界扩散控制生长的值。Ni和Ni 3 P相的晶粒生长活化能分别估计为210和180 kJ mol−1。纳米晶和超细晶试样（约40-400 nm）在屈服之前断裂，而较大晶粒试样（>400 nm）显示塑性变形。断裂强度和断裂应变不仅取决于晶粒尺寸，而且取决于Ni 3 P晶粒的连通性，其中裂纹优先形核。
The relationship between microstructural evolution and mechanical properties in Ni–4.4mass% P alloy was systematically examined. As-electrodeposited Ni–4.4mass% P alloy consists of grains having an average grain size of 37 nm and texture strongly oriented to (111). Phosphorus is entirely in solid solution. Heat treatment induces precipitation of Ni3P phase. Rapid grain growth occurs only at the initial stage of heat treatment, and saturated at all the annealing temperatures, even at temperatures higher than 873 K (0.51Tm). Grain growth exponents n in Ni and Ni3P phases were found to be 4.5–5.9 and 4.9–5.4, respectively. These values are close to those for grain boundary diffusion-controlled growth. Activation energies for grain growth in Ni and Ni3P phases were estimated as 210 and 180 kJ mol−1, respectively. The nanocrystalline and ultrafine-grained specimens (about 40–400 nm) fractured prior to yielding, while the larger grained specimens (>400 nm) showed plastic deformation. Fracture strength and fracture strain depend not only on grain size but also on connectivity of Ni3P grains, where cracks were preferentially nucleated.