The compressive strength of two kinds of titanium alloys was investigated in the wide temperature range from 78K to 723K and the strain rate range from 10^-4/sec to 10³/sec. It was found that the flow stress increased with the rise of strain rate and with the decrease of temperature, while it was completely independent of temperature and strain rate history.
The thermal component of the stress, ≅σ^*, was analysed with the thermally activated process concept and was uniquely characterized only with the Larson-Millar parameter ξ^*=Tln(ε₀/ε) in the relatively low strain rate range. The athermal component of the stress, ≅σμ, was a function of strain only and consequently the whole stress-strain relation at a certain given temperature and strain rate can be predicted.
The temperature change due to the adiabatic heat generation was taken into account to evaluate the stress at high strain rates and provided a plausible explanation of the experimental results.