Evolution of mechanical properties of cast Zr₅₀Cu ₄₀Al₁₀ glassy alloys by structural relaxation

The volume of a quenched glassy alloy is a variable of cooling rates during the amorphization. Hence a change in the volume caused by the structural relaxation can be regarded as a degree of amorphousness. The density of Zr ₅₀Cu₄₀Al₁₀ bulk glassy alloys (BGAs) increases linearly with the annealing temperature below the glass-transition temperature (T_g). With increasing the annealing temperature, the tensile strength and Vickers hardness show constant values, whereas the Young's moduli and Charpy impact values become larger and smaller, respectively. Especially, Charpy impact values of Zr-Cu-Al BGAs have a linear relationship with the relative value of excessive free volume, which correspond to the volume-change ratio caused by the full structural relaxation.