Dynamic recrystallization kinetics in alpha phase of as-cast Ti-6Al-2Zr-1Mo-1V alloy during compression at different temperatures and strain rates

作者：Quan Guo zheng^*; Wu Dong sen; Luo Gui chang; Xia Yu feng; Zhou Jie; Liu Qing; Gao Lin

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2014, 589: 23-33.

DOI：10.1016/j.msea.2013.09.069

• Dynamic reaystallization
• Strain hardening rate
• Critical strain
• Volume fraction
• Titanium alloy

In order to evaluate the dynamic recrystallization (DRX) behavior of as-cast Ti-6A1-2Zr-lMo-1V alloy, a series of compressions with a height reduction of 60% were performed in a temperature range of 1073-1323 K (0.55-0.68T(m)) and a strain rate range of 0.01-10 s(-1) on a Gleeble1500 thermo-mechanical simulator. By the regression analysis for conventional hyperbolic sine equation, the activation energy of DRX was determined as Q=933.3233 kJ mol(-1), and a dimensionless parameter controlling the stored energy were determined as Z/A = eexp[(933.3233 x 10(3))/8.31T]/6.17726 x 1036. According to the strain hardening rate curves (d sigma/d epsilon versus sigma), three characteristic parameters including the critical strain for DRX initiation (epsilon(c)), the strain for peak stress (epsilon(p)), and the strain for maximum softening rate (epsilon*) were identified. A modified Avrami type equation X-DRX = 1-exp{-[(epsilon-epsilon(c)/epsilon*)(m)} was introduced to characterize the evolution of DRX volume fraction in a-phase temperatures under 0.59Tm, in which epsilon(c), epsilon* and m were described as epsilon(c) = 0.028774(Z/A) 0.04665, epsilon* = 0.45379(Z/A)(-6.118274e-4) and m=4.133402 respectively. The evolution of DRX volume was described as the following: for a fixed strain rate, the strain required for the same amount of DRX volume fraction increases with decreasing deformation temperature, in contrast, for a fixed temperature, it increases with increasing strain rate. Finally, the theoretical predictions were validated by the microstructure graphs.

• 出版日期2014-1-1
• 单位重庆大学