Overheating effects on thermal stability and mechanical properties of Cu36Zr48Ag8Al8 bulk metallic glass

A pronounced effect of overheating is observed on the thermal stability and mechanical properties of Cu36Zr48Ag8Al8 bulk metallic glass. Higher overheated temperature enhances the thermal stability of bulk amorphous alloys, corresponding to higher specific-heat capacity and the smaller initial defect concentration. And a threshold overheating temperature is found for the fully amorphous structure. Bulk amorphous alloys exhibit good compressive plasticity at small overheat levels, whereas the compressive fracture strength and micro-hardness exhibit a significant increase first and then a slightly decrease. Mechanical properties of BMGs can be tailored in certain extent by controlling the overheated level, which is correlated with free volume and residual stresses.