钒和金纳米晶体晶粒长大临界温度的“尺寸—形状”模型

处于亚稳态的纳米晶体中晶粒在一定临界温度开始长大变为粗晶,该临界温度依赖晶粒中原子迁移所需的能量.根据纳米晶体中晶粒长大的微观过程以及晶粒中原子迁移能量状态与晶粒尺寸、形状的相关性,建立了计算纳米晶粒长大临界温度的"尺寸—形状"模型.基于该模型计算了钒和金纳米晶体中晶粒长大的临界温度,结果表明纳米晶粒长大的临界温度随晶粒尺寸的减少而降低,并且与晶粒形状相关,表现了明显的"尺寸—形状"效应.该理论模型计算结果与实验结果相吻合.

The Size-shape Model of Critical Temperature for Grain Growth in Nano V and Au

At a certain critical temperature,metastable nanocrystalline grains begin to grow into coarse grains.The critical temperature depends on the energy of atom migration in nanocrystalline.Based on the microscopic process of grain growth in nanocrystals,combined with correlations of the transfer energy to the size and shape of grain,in order to calculate the critical temperature of grain growth,the size - shape model is proposed in this paper.The calculated results of critical temperature of vanadium and gold nanocrystalline grain growth show that the critical temperature decreases with the size of grain reducing.Moreover,the critical temperature is related to the shape of grain,showing the obvious size-shape effect.The theoretical results are consistent with the available experimental results.