中文摘要：

Ti、Cr和Al的添加改变了铌基固溶体合金的弹性常数，从而改变了其点阵位移势（UP-N）。采用表面能（γs）与点阵位移势（UP-N）之心之比可预测合金的室温断裂韧性。Ti的添加降低了点阵位移势、提高了位错的移动能力，从而提高了铌基固溶体合金的室温断裂韧性；而Cr和Al的作用与Ti相反。简要介绍了K．S．Chan等建立的室温断裂韧性计算模型，同时介绍了合金化元素Ti、Mo、Hf和B等对铌硅化物基合金室温断裂韧性的影响。其中Ti、Hf和B的添加能提高铌硅化物基合金的室温断裂韧性。

英文摘要：

The additions of alloying elements such as Ti, Cr and Al change the elastic properties, consequently influence Perierls-Nabbarro barrier energy （UP-N） of Nb-based solid solution alloys. The ratio of surface energy （γs） to UP-N can be employed to predict the fracture toughness of Nb-based solid solution alloys. The Ti addition reduces UrN,promotes dislocation mobility, and thus enhances the fracture toughness of N b-based solid solution alloys. The roles of both Cr and Al additions are opposite to that of Ti addition. The calculation model for the room temperature toughness established by K. S, Chan is described briefly in the present paper, The influences of alloying elements such as Ti,Mo,Hfand B on the fracture toughness of Nb silicide-based alloys are also described. The additions of Ti, Hf and B increase the fracture toughness of Nb silicide-based alloys.