The characterization of strain rate effects near glass transition temperature (Tg) gives important information on flow behavior of metallic glasses (MGs). For this purpose, the tensile strain rate jump test was carried out near glass transition temperature to evaluate the flow behaviors of ZrCoAl(Si) MG ribbons. The primary thermal analyses showed that the Si minor addition into the ZrCoAl alloy leads to the betterment of thermal stability and the glass forming ability (GFA), correlated with the small size of Si atoms and subsequent formation of denser atomic clusters and thermodynamically liquid stabilization in the system. The tensile strain rate jump test indicated that minor adding of Si element decreases the sensitivity of glassy alloy to the flow stress and improves the stability of amorphous structure under increase in the strain rate and applied temperature. It was also observed that the viscosity behavior is more stable with the increase of the strain rate and temperature in the Si-added sample, implying the high capability of viscoplastic response in this state.
Metallic glass; flow stress; thermal stability; deformation