Effect of structural relaxation on mechanical behavior of a Zr-based bulk-metallic glass

Using the instrumented nanoindentation and differential-scanning calorimetry, the effect of the structural relaxation at the elevated temperature on the Zr52.5Cu17.9Ni14.6Al10.0Ti5.0 bulk-metallic glass was investigated. The structural relaxation did not exert a significant influence on the plastic-flow behavior. However, the relaxation enhanced both the hardness and elastic modulus substantially. The decrease in the structural relaxation enthalpy before the glass transition indicates that the relaxation reduced the free volume significantly. The increase in the hardness and elastic modulus is attributed to the reduction in the free Volume that resulted from the relaxation.