Influence of Strain Rate on the Thermo-Mechanical Compressive Response of Metastable Beta Ti-15Mo (wt.%)

Titanium (Ti) and its alloys, known for their high strength-to-weight ratio, are widely used in defense, aerospace, and automotive industries. Components in these sectors often experience dynamic loading and high temperatures, with strain rates ranging from 10² to over 10⁴ s⁻¹ and temperatures up to 500 to 1000°C. Twinning Induced Plasticity (TWIP) alloys, such as Ti-15Mo (wt.%), are of particular interest due to their toughness and energy absorption capacity. This study investigates the effects of loading rate and temperature on the compressive behavior and microstructural evolution of Ti-15Mo (wt.%) under dynamic conditions. Quasi-static (10⁻³ s⁻¹) and dynamic (up to 10³ s⁻¹) compression experiments are performed using a standard compression frame and modified Kolsky bar with integrated heating. Strain rate sensitivity is examined at temperatures up to 450°C, with imaging techniques including 2D digital image correlation (DIC) and thermal imaging. Post-mortem analysis via electron backscatter diffraction (EBSD) reveals that at high strain rates, twinning is the dominant deformation mechanism, but it decreases with increasing temperature. At quasi-static rates, dislocation slip becomes the primary mechanism at higher temperatures, with ω phase precipitates observed.