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

Abstract

Abstract 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 ‒1 to the true strain of 0.7 were conducted to obtain the essential data about stress σ and strain ε . By further transforming the relationship of σ versus ε into the relationship of strain hardening rate d σ /d ε versus σ , two characteristic strains at the beginning of DRX (critical strain ε c ) and at the peak stress (peak strain ε p ) were identified from the d σ /d ε-σ curves. Sequentially, the parameters in the JMAK equation were determined from the linear fitting of the different relationships among critical strain ε c , peak strain ε p and deformation conditions (including temperature T , strain rate <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mover> <m:mi>ε</m:mi> <m:mo>˙</m:mo> </m:mover> </m:math> $\dot \varepsilon $ and strain ε ). The as-obtained JMAK equation was expressed as X DRX =1-exp[-0.0053(( ε-ε c )/ ε c ) 2.1 ], where ε c =0.6053 ε p and ε p =0.0031 <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:mover> <m:mi>ε</m:mi> <m:mo>˙</m:mo> </m:mover> </m:math> $\dot \varepsilon $ 0.0081 exp(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.