Predicting hot deformation behaviors under multiaxial loading using the Gurson-Tvergaard-Needleman damage model for Ti–6Al–4V alloy sheets

• Published in: European journal of mechanics, A, Solids A, Solids, 2021-05, Vol.87, p.104227, Article 104227
• Main Authors: Bong, Hyuk Jong, Kim, Daeyong, Kwon, Yong-Nam, Lee, Jinwoo
• Format: Article
• Language: English
• Subjects: Axial stress; Constraining; Damage assessment; Domes; Empirical analysis; Finite element analysis; Fracture behavior; High temperature; Hot deformation; Hot forming; Mechanical properties; Metal sheets; Modelling; Multi-axial loading; Plane strain; Plastic deformation; Plasticity; Strain rate sensitivity; Titanium alloys; Titanium base alloys
• ISSN: 0997-7538; 1873-7285
• DOI: 10.1016/j.euromechsol.2021.104227

In this study, the hot deformation behavior of Ti–6Al–4V alloy sheets was investigated at a temperature of 650 °C after being subjected to various forming histories. The studied behaviors included empirical testing of uniaxial stress, plane strain, and biaxial stretch deformation modes. The results were then quantified using a damage modeling approach. Limiting dome height tests at elevated temperatures were conducted to characterize the mechanical behavior under various deformation modes. Constitutive modeling followed the Gurson-Tvergarrd-Needleman damage model of plasticity, including flow softening, strain rate sensitivity, and adiabatic heating. The material constants of the model were calibrated using hot uniaxial tension at various strain rates. Thermo-mechanical finite element simulations coupled with the plastic and damage modeling were conducted to predict the plastic deformation and failure behaviors of the Ti–6Al–4V alloy sheets under hot forming conditions. The damage behavior for hot uniaxial tension and limiting dome height tests was also analyzed via the hybrid methods of fractography and quantitative assessment. The macro-damage quantitative simulations reproduced the observed plastic behaviors, including the load-displacement responses and the fracture states of Ti–6Al–4V alloy sheets at elevated temperatures, after experiencing complex-forming conditions. The research results thus provide a basis of optimal hot forming process for titanium alloys. [Display omitted] •The plastic and damage behaviors of Ti–6Al–4V sheets under hot forming condition were investigated.•The analysis on failure prediction using GTN and flow softening model was conducted.•An improvement in computer simulation of Ti–6Al–4V sheets was observed.•The influence of hot forming parameters of Ti–6Al–4V on simulations was discussed.