中温变形下TC4合金绝热剪切带研究（英文）

Adiabatic Shear Band of TC4 Alloy during Warm Comp-ression

研究了TC4合金在中温变形过程中形成的绝热剪切带,应变速率为50 s-1,变形温度为560-660℃。结果表明变形温度对绝热剪切带的形成有很大影响。剪切带宽度随着变形温度的升高从85μm增加至140μm。因为发生了加工硬化和绝热剪切带中产生的细晶强化作用,绝热剪切带对应的维氏显微硬度比基体高。讨论了绝热剪切带中微观组织演变规律,大应变以及高温使得绝热剪切带中发生了动态再结晶,形成了等轴的再结晶晶粒,再结晶晶粒尺寸为200 nm左右。本研究中形成的绝热剪切带具有形变剪切带和相变剪切的特点。

The adiabatic shear band （ASB） forming in the warm compression of TC4 titanium alloy was investigated at a strain rate of 50 s-1 and the deformation temperatures ranging from 560 to 660 ℃. The results show that the deformation temperature affects significantly the formation of the ASBs. The shear band width increases from 85 μm to 140 μm as the deformation temperature increases. The corresponding Vickers micro-hardness values of the ASB are higher than that of the matrix due to the strain hardening and fine grains in ASB. Meanwhile the microstructure evolution mechanism within the ASB was discussed. Large strain and high temperature make the occurrence of dynamic recrystallization （DRX） in ASB, leading to the formation of equiaxed DRX grains with a grain size about 200 rim. The ASBs in this study have both the characteristics of deformed band and transformed band.