Modeling and Finite Element Analysis for the Dynamic Recrystallization Behavior of Ti-5Al-5Mo-5V-3Cr-1Zr Near β Titanium Alloy During Hot Deformation

Evolution for the dynamic recrystallization (DRX) volume fraction of Ti-5Al-5Mo-5V-3Cr-1Zr near β titanium alloy during hot deformation was characterized by using the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation. To determine the equation parameters, a series of thermal simulation experiments at the temperature of 1023–1098 K and strain rate of 0.001–1 s‒1to the true strain of 0.7 were conducted to obtain the essential data about stress σand strain ε. By further transforming the relationship of σversus εinto the relationship of strain hardening rate dσ/dεversus σ, two characteristic strains at the beginning of DRX (critical strain εc) and at the peak stress (peak strain εp) were identified from the dσ/dε-σcurves. Sequentially, the parameters in the JMAK equation were determined from the linear fitting of the different relationships among critical strain εc, peak strain εpand deformation conditions (including temperature T, strain rate ε˙$\dot \varepsilon $and strain ε). The as-obtained JMAK equation was expressed as XDRX=1-exp[-0.0053((ε-εc)/εc)2.1], where εc=0.6053εpand εp=0.0031ε˙$\dot \varepsilon $0.0081exp(28,781/RT). Finally, the JMAK equation was implanted into finite element program to simulate the hot compression of thermal simulation experiments. The simulation predictions and experimental results about the DRX volume fraction distribution showed a good consistency.