学术文献库

Experimental data on the compressive strength $σ_{\rm max}$ versus strain rate ${\dot \varepsilon}_{\rm eng}$ for metallic glasses undergoing uniaxial compression shows significantly different behavior for different alloys. For some metallic glasses, $σ_{\rm max}$ decreases with increasing ${\dot \varepsilon}_{\rm eng}$, for others, $σ_{\rm max}$ increases with increasing ${\dot \varepsilon}_{\rm eng}$, and for others $σ_{\rm max}$ versus ${\dot \varepsilon}_{\rm eng}$ is nonmonotonic. Using numerical simulations of metallic glasses undergoing uniaxial compression at nonzero strain rate and temperature, we show that they obey a universal relation for the compressive strength versus temperature, which determines their mechanical response. At low ${\dot \varepsilon}_{\rm eng}$, increasing strain rate leads to increases in temperature and decreases in $σ^*_{\rm max}$, whereas at high ${\dot \varepsilon}_{\rm eng}$, increasing strain rate leads to decreases in temperature and increases in $σ^*_{\rm max}$. This non-monotonic behavior of $σ^*_{\rm max}$ versus temperature causes the nonmonotonic behavior of $σ^*_{\rm max}$ versus ${\dot \varepsilon}_{\rm eng}$. Variations in the internal dissipation change the characteristic strain rate at which the nonmonotonic behavior occurs. These results are general for a wide range of metallic glasses with different atomic interactions, damping coefficients, and chemical compositions.