三种微观组织的Ti-46．5Al-2Nb-2Cr高温动态力学行为的实验研究

Experimental Study of Ti-46.5Al-2Nb-2Cr with Three Different Microstructures under Elevated Temperatures and High Strain Rate

对等轴(NG),近片层(NL)和双态(DP)组织的Ti-46.5Al-2Nb-2Cr在室温至840℃,应变率分别为0.001s-1,320s-1,800s-1和1350s-1下的拉伸力学行为进行了实验研究,初步揭示了三种微观组织的TiAl的韧脆转变温度均随应变率的升高而升高;三种微观组织的TiAl动态下的高温综合力学性能优于准静态下的性能——动载下的强度均明显高于静载下的强度,且呈现出"高温高速韧"的特性。TiAl有可能成为一种抗冲击的高温结构材料。

The tensile behavior of Ti-46.5Al-2Nb-2Cr with near gamma （NG）, near lamellar （NL） and duplex （DP） microstructures ,were investigated in temperature ranging from room temperature to 840℃ and under strain rates of 0. 001, 320, 800 and 1350s^-1 respectively. Results show that the brittle to ductile transition temperature of all TiAls increases with the strain rate increase. The comprehensive mechanicalbehavior of all TiAls under high strain rate loading is better than those under quasi-static loading, including the strength and plastic deformation. TiAl may become a structural material that is capable of suffering both high temperature and impact loading.