Study of the hot deformation behaviour in Ti–5Al–5Mo–5V–3Cr–1Zr

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2011-10, Vol.528 (28), p.8277-8285
• Main Authors: Warchomicka, F., Poletti, C., Stockinger, M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Beta; Cross-disciplinary physics: materials science; rheology; Deformation; Dynamics; EBSD; Elasticity. Plasticity; Electron microscopy; Exact sciences and technology; Materials science; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Other heat and thermomechanical treatments; Physics; Recovery; Recrystallization; Restoration; Strain rate; Thermomechanical processing; 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.2011.07.068

► EBSD is imperative to determine the predominant mechanism active during deformation. ► Mechanisms of restoration in Ti55531 occur mainly in the beta phase. ► Dynamic recovery is followed by continuous dynamic recrystallization. Structural applications of near beta titanium alloys are gradually increasing in the aerospace industry because of their high specific mechanical properties and good corrosion resistance. Furthermore, a wide range of microstructures can be obtained by thermomechanical processes. This work determines by the use of EBSD technique the mechanism of restoration active in the near beta titanium alloy Ti–5Al–5Mo–5V–3Cr–1Zr for deformations in both α + β and β field near to the β transus temperature ( T β = 803 °C). Hot compression tests are carried out up to 0.7 true strain by means of a Gleeble ® 1500 machine at strain rates of 0.01, 0.1 and 1 s −1. Dynamic recovery of β phase and rotation of the α grains take place predominantly in the α + β field. Further deformation produces continuous dynamic recrystallization of the β phase influenced by the strain rate. Dynamic recovery is observed during deformation above the T β, where the misorientation is increasing towards the grain boundaries forming new small grains with a substructure at high strain rates and larger deformation. The stress exponent and the apparent activation energy for the sinh constitutive equations are determined and the microstructural features are correlated with the Zener–Hollomon parameter.