机械合金化的Cu基纳米晶合金热力学稳定性（英文）

Thermodynamic Stabilization of Mechanical Alloying Cu Based Nanocrystalline Alloys

在纳米结构的金属及合金中,随着晶粒尺寸的下降,晶界体积分数显著增加,使得晶粒长大的驱动力提高,因此纳米金属在加热时(甚至是室温下)是不稳定的,限制了其加工与应用。本文对Trelewicz/Schuh(TS)模型进行了修正,并利用修正的模型对Cu-6.5at%Zr、Cu-6.5at%Nb纳米晶合金的热力学稳定倾向进行了计算研究。实验利用机械合金化的方法制备这两种纳米晶合金,并在不同温度下进行退火。实验结果及理论计算表明,随着溶质原子的加入及在晶界的偏聚,这两种纳米晶合金的晶粒长大得到抑制,热力学稳定性提高。

In nanostructured alloys,grain boundary volume fraction significantly increases with the decreasing of grain size,which leads to high driving force for grain growth. So nanocrystalline metals and alloys are unstable when heating or even at room temperature,which limits its processing and application. Thermodynamic stabilization tendency of Cu-6. 5at% Zr and Cu-6. 5at% Nb nanocrystalline alloys were calculated and predicted based on the modified Trelewicz /Schuh（TS） model. These two nanocrystalline alloys were prepared by mechanical alloying and annealed at different temperature. Experiment results and theoretical prediction show that,with the addition and segregation at grain boundary of solute atom,grain growth is retarded and thermodynamics stability of these two alloys is enhanced.