Finite element simulation of the thermomechanical effects of forging on dynamic re-crystallization of aerospace-grade Ti 6Al 4V alloy

Abstract

ABSTRACT This study presents a detailed technical analysis of the influence of strain rate and temperature on the microstructure and mechanical properties of the Ti 6Al 4V alloy during forging. As a process governed by compressive forces, forging involves critical parameters such as temperature, strain rate, friction and cooling rate, all of which collectively determine the resulting microstructure. Motivated by the stringent requirements of the aerospace industry; where even minimal variations in grain size and phase distribution can significantly affect fatigue life, tensile strength and overall component reliability, the investigation employs finite element simulations to model the forging of cylindrical Ti 6Al 4V billets at temperatures ranging from 800 to 1000 °C and strain rates from 0.025 to 0.500 s-1. Frictional conditions and die temperatures are also incorporated to better approximate realistic industrial scenarios. Particular emphasis is placed on dynamic recrystallization (DRX), grain size evolution and mesh refinement strategies. The study further evaluates the contributions of dynamically recrystallized, statically recrystallized, and retained parent grains to the final microstructure. Additionally, it addresses key modeling challenges, including the accuracy of constitutive models, the local sensitivity of frictional behavior and the emergence of microstructural gradients under single-pass versus multi-step forging sequences.