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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 oC。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 formed during the mid-temperature deformation of TC4 alloy was investigated. The strain rate was 50 s-1 and the deformation temperature was 560-660 oC. The results show that the deformation temperature has a great influence on the formation of adiabatic shear band. The shear band width increases from 85μm to 140μm with increasing deformation temperature. The Vickers microhardness corresponding to the adiabatic shear band is higher than that of the matrix due to the grain refinement generated during work hardening and adiabatic shear banding. The evolution of microstructure in the adiabatic shear band was discussed. The large recrystallization occurred in the adiabatic shear band due to the large strain and the high temperature, forming an equiaxed recrystallized grain with a recrystallized grain size of about 200 nm. The adiabatic shear band formed in this study has the characteristics of deformation shear band and phase change shear.