Strain Rate Sensitivity of Stress-strain Curves in a Ti-Fe-O Alloy

Abstract

The effect of strain rate on stress-strain curves of an α-type Ti-Fe-O alloy was investigated at the strain rate between 2.8×10^-5 to 2.7×10^-2 s^-1 at 293K. Zero strain rate curve, "Base Curve" was estimated by multiple interrupted crosshead displacement dwell test every 0.02 strain in case of the strain rates of 2.8×10^-4 and 2.8×10^-5. The relaxation saturated stress-strain points made a single stress-strain curve, "Base Curve". Base Curve and stress-strain curves at various strain rates were parallel. This means the stress-strain curves can be separated into strain dependent component and strain-rate dependent component. When Base Curve is fitted with Swift's equation, the stress-strain curves are interpreted as follows, σ=875.5(0.021+ε)^0.176+313.3ε^0.046, where σ: Stress(MPa), ε: strain and ε: strain rate.