Comparative experimental study of the dynamic properties and adiabatic shear susceptibility of titanium alloys

Abstract

Titanium and titanium alloys are prone to adiabatic shear failure when deformed at high strain rates due to their low coefficients of specific heat and thermal conductivity. Comparative study of the adiabatic shear susceptibility of titanium alloys are seldom reported in the literature. To further understand this topic, the mechanical response of five representative titanium alloys, i.e. commercially pure titanium (TA2, α), Ti-6.5Al–2Zr–1Mo–1V (TA15, near α), commercially Ti–6Al–4V (TC4, α+β), Ti–5Al–5Mo–5V–1Cr–1Fe (TC18, near β) and Ti–3Al–8V–6Cr–4Mo–4Zr (TB9, β), is characterized over a wide range of strain rates (ranging from 0.001 to 4000s−1) and temperatures (ranging from 293 to 673K). The findings of this experimental demonstrate that the yield stress of TA2 is the lowest, while it is the highest for TC18. The strain hardening effect of titanium alloys is prominent at low strain rate, while it may be decreased at high strain rates due to the presence of β-phase stabilizers. In addition, the mechanical behavior of titanium alloys is sensitive to strain rate and test temperature. The results also suggest that the formation of ASB is related to the applied strain rate and initial test temperature, and higher test temperature and strain rate promote the occurrence of adiabatic shear localization in dynamic deformation. Moreover, for titanium alloys, a lower strain-hardening coefficient and higher strength does not correspond to high sensitivity to adiabatic shear failure, and the dynamic failure energy, with its constant value, seems to be the best indicator of ASB failure. Furthermore, our results and analysis are important in enhancing the understanding of the dynamic properties and adiabatic shear susceptibility of titanium alloys. Based on this work, engineers can choose the optimal titanium alloy to fabricate components according to the service requirements to fully utilize the potential of the material.