预应变对TA2纯钛板室温滞后回弹的影响

The effect of pre-strain for the time-dependent springback of TA2 pure titanium at room temperature

摘要:

为探明室温下不同预应变对TA2钛板滞后回弹的影响，采用万能试验机进行了不同预应变的滞后回弹实验。预应变分别取自均匀塑性变形区、分散性失稳区以及集中性失稳区。拉伸变形组织采用光镜和透射电镜进行表征。结果表明，TA2钛板卸载后的滞后回弹效应明显，均匀变形区和失稳区的滞后回弹应变(TDSS)累积值随预应变的提高分别以不同的指数规律增长。组织分析表明，孪晶数量与TDSS变化规律相关；失稳区的加载历史对TDSS和弛豫饱和时间tIP产生了一定影响。

Abstract:

In order to reveal the effect of pre-strain for the time-dependent springback, the TA2 titanium sheets were drawn under different pre-strains by using the universal testing machine. The microstructures of the tested samples were both characterized by optical microscope and transmission electron microscope to infer the basis of the anelastic behavior. The results reveal that the time-dependent response of TA2 was obvious. The time-dependent-springback strain(TDSS) presented different exponential change laws in different plastic deformation zones. Both the TDSS and the amount of deformation twin increased as the pre-strain went up. The loading history and the interaction between dislocation and twin affected the TDSS and the relaxation-saturation time tIP.