中文摘要：

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。对Trelewicz／Schuh（TS）模型进行了修正，并利用修正的模型对Cu—Sn纳米晶合金的热力学稳定倾向做了计算研究。利用机械合金化的方法制备不同溶质含量的Cu-Sn纳米晶合金，在不同温度下进行退火实验。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，Cu-Sn纳米晶合金的晶粒长大得到抑制，热力学稳定性提高。

英文摘要：

In nanostructured metals and alloys, grain boundary volume fraction greatly increases with the decreasing of grain size, which leads to high driving force for grain growth. So nanocrystalline metals are unstable when heated or even at room temperature. Thermodynamic stabilization tendencies of Cu-Sn nanocrystalline alloys were calculated and predicted based on the modified Trelewicz/Schuh （TS） model. A series of Cu-Sn nanocrystalline alloys with different solute contents were prepared by mechanical alloying and annealed at different temperatures. Experimental results and theoretical prediction show that grain growth of Cu-Sn nanocrystalline alloys are retarded with the addition and segregation at grain boundary of solute atoms, and thermodynamic stabilities of these alloys are enhanced.