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利用表面机械研磨处理(SMAT)技术在纯Ni上制备一定厚度的纳米晶表层,利用X射线衍射(XRD)和透射电镜(TEM)研究了纳米晶Ni的晶粒生长动力学,计算了描述晶粒生长动力学的时间指数n和晶粒生长激活能Q。研究表明,纳米晶Ni在423～723 K退火时的时间指数n约为0.14。当纳米晶Ni在423～523 K退火时,其晶粒生长激活能Q为32.1 kJ/mol,表明在这一温度区间内晶粒生长由晶界和亚晶界的微结构重新排列所控制;当纳米晶Ni在523～723 K退火时,晶粒生长激活能Q为121.3 kJ/mol,表明在这一温度区间内晶粒生长由晶界扩散所控制。TEM观察表明纳米晶Ni在较高温度下退火时出现异常的晶粒长大现象。
The nanocrystalline surface layer was prepared on pure Ni by surface mechanical milling (SMAT) technique. The crystal growth kinetics of nanocrystalline Ni was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) The time index n of grain growth kinetics and the grain growth activation energy Q. The research shows that the time index n of nanocrystalline Ni annealed at 423 ~ 723 K is about 0.14. When the nanocrystalline Ni is annealed at 423-523 K, the crystal growth activation energy Q is 32.1 kJ / mol, indicating that the grain growth is controlled by the rearrangement of the microstructure at grain boundaries and subgrain boundaries in this temperature range. When the nanocrystalline Ni is annealed at 523-723 K, the crystal growth activation energy Q is 121.3 kJ / mol, indicating that the grain growth is controlled by the grain boundary diffusion in this temperature range. TEM observations indicate that abnormal grain growth occurs in nanocrystalline Ni annealed at higher temperatures.