Simulated and experimental investigation on discontinuous dynamic recrystallization of a near-α TA15 titanium alloy during isothermal hot compression in βsingle-phase field

近α钛合金TA15在β单相区等温变形过程中不连续动态再结晶的模拟与实验研究(英文)

A cellular automaton（CA） modeling of discontinuous dynamic recrystallization（DDRX） of a near-α Ti-6Al-2Zr-1Mo-1V（TA15） isothermally compressed in the β single phase field was presented.In the CA model,nucleation of the β-DDRX and the growth of recrystallized grains（re-grains） were considered and visibly simulated by the CA model.The driving force of re-grain growth was provided by dislocation density accumulating around the grain boundaries.To verify the CA model,the predicted flow stress by the CA model was compared with the experimental data.The comparison showed that the average relative errors were10.2%,10.1%and 6%,respectively,at 1.0,0.1 and 0.01 s^-1 of 1020 ℃,and were 10.2%,11.35%and 7.5%,respectively,at 1.0,0.1and 0.01 s^-1 of 1050 ℃.The CA model was further applied to predicting the average growth rate,average re-grain size and recrystallization kinetics.The simulated results showed that the average growth rate increases with the increasing strain rate or temperature,while the re-grain size increases with the decreasing strain rate;the volume fraction of recrystallization decreases with the increasing strain rate or decreasing temperature.

介绍了元胞自动机法模拟钛合金Ti-6A1—2Zr—1Mo—1V(TA15)在β单相区等温压缩过程中的不连续动态再结晶现象。通过元胞自动机模型,动态地模拟了再结晶的形核和后续长大。再结晶晶粒长大的驱动力由晶界处位错密度的演化提供。为了验证本CA模型的正确性,将通过CA模型预测所得的应力-应变曲线与实验值进行对比。对比结果表明,在1020℃,应变速率1.0、0.1、0.01 s^(-1)的条件下,二者平均相对误差分别为10.2%、10.1%和6%;而在1050℃,应变速率1.0、0.1、0.01 s^(-1)的条件下,二者平均相对误差分别为10.2%、11.35%和7.5%,验证了模型的可靠性。另外,基于该CA模型预测研究了再结晶晶粒尺寸、长大速度和再结晶动力学特征。结果表明,再结晶晶粒长大速率随着应变速率或温度的升高而升高;再结晶晶粒尺寸随着应变速率的降低而增加;再结晶体积分数随着应变速率的增加或温度的降低而降低。