Simulation of plastic deformation in Ti-5553 alloy using a self-consistent viscoplastic model

Titanium alloy Ti-5Al-5Mo-5V-3Cr (Ti-5553) is a near beta alloy used in structural aircraft components because of its excellent mechanical properties. Simulating the mechanical response of this material using constitutive models is an important step in understanding the relationship between its microstructure and properties. Uniaxial compression tests were conducted at temperatures both below and above the beta transus and at different loading rates. A viscoplastic self-consistent (VPSC) model was used to match the stress-strain response of the Ti-5553 alloy based on uniaxial compression tests across a range of temperatures and strain rates. Sets of parameter values were determined for two different hardening models, namely the modified Voce model, which is empirical, and the Mechanical Threshold Stress (MTS) model, which is based on dislocation theory. No consistent trends in the Voce parameter values were found as a function of temperature or strain rate. By contrast, the physically-based MTS model, which is explicitly designed to cover wide ranges of deformation conditions, was able to fit a wide range of temperatures and strain rates. It was further validated by comparison with experimental measurements with other b titanium alloys that had similar compositions. (C) 2017 Elsevier Ltd. All rights reserved.