应变速率循环法是一种新式的超塑性试验方法,即试样在拉伸变形过程中,应变速率的大小按预定规律不断连续循环变化,直至试样拉断,从而获得材料的超塑性力学性能参数。本文采用这种方法研究了Ti-10V-2Fe-3Al合金的超塑性。结果表明,该合金具有良好的超塑性,同传统的恒应变速率拉伸试验相比,应变速率循环能有效地提高合金的超塑性能,获得更大的延伸率和更高的应变速率敏感性指数m值。例如,在最佳变形温度800℃条件下,延伸率从296%增大到440%,m值从0.36提高到0.48。应变速率循环为该合金超塑技术的应用开辟了新的途径。

The newly developed cyclic strain-rate method implies that in a superplastic tensile test the strain-rate varies in accordance with a given cyclic regime until the specimen breaks down, obtaining the superplastic mechanical parameters of a certain metallic material. in this paper, this method has been used to investigate the superplastic behaviour of Ti-10V-2Fe-3Al alloy. The test results show that this method, if compared with the constant strain-rate method. can effectively improve the superplastic behavior of this alloy in terms of the higher values of elongaftion and greater strain-rate sensitivity exponent. For example, at the optimal deformation temperature 800℃, the elongation is raised from 296 to 440% and the m-value from 0.36 to 0.48. The cyclic strain-rate method provides a new approach to evaluate the superplastic behaviour of Ti-10V-2Fe-3Al alloy.