The construction of constitutive model and identification of dynamic softening mechanism of high-temperature deformation of Ti–5Al–5Mo–5V–1Cr–1Fe alloy

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2014-10, Vol.615, p.42-50
• Main Authors: Liang, Houquan, Guo, Hongzhen, Nan, Yang, Qin, Chun, Peng, Xiaona, Zhang, Jingli
• Format: Article
• Language: English
• Subjects: Applied sciences; Cold working, work hardening; annealing, quenching, tempering, recovery, and recrystallization; textures; Condensed matter: structure, mechanical and thermal properties; Constitutive model; Constitutive relationships; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Deformation; Dislocation evolution; Dislocations; Dynamic recrystallization; Dynamic softening mechanism; Dynamics; Exact sciences and technology; High-temperature deformation; Linear defects: dislocations, disclinations; Materials science; Mathematical models; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Physics; Softening; Structure of solids and liquids; crystallography; Titanium alloys; Titanium base alloys; Treatment of materials and its effects on microstructure and properties
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2014.07.050

The high-temperature deformation behaviors of Ti–5Al–5Mo–5V–1Cr–1Fe alloy were investigated through the isothermal compression experiment. The dislocation evolution in the working-hardening stage has been analyzed and the corresponding constitutive model has been constructed. The dynamic softening mechanism has been identified with the relationship between the saturated dislocation density and dynamic recrystallization (DRX) critical density. The dependence on deformation parameters has been discussed and a concept of critical strain rate ε̇C has been proposed. A dynamic softening map has been designed to predict the corresponding softening behaviors under certain deformation conditions. The constitutive model based on dislocation evolution has been extended to overall deformation incorporating dynamic softening behaviors and their deviations have been explained by introducing the processing map.