Abstract
Annealing induced embrittlement often represents a challenge to synthesize bulk metallic glasses (BMGs) with enhanced ductility using powder metallurgy techniques. Spark plasma sintering (SPS) uniquely provides a fast heating rate (400 not equal to /min) and accurate temperature control to study the effects of structural relaxation and partial crystallization on the mechanical properties of BMGs. In this study, the crystallization behavior during SPS and the corresponding mechanical properties of (Cu sub(0.5)Zr sub(0.5)) sub(100-x)Al sub(x) (x=0, 2.5, 5, 7.5 and 10) BMGs were investigated. In the supercooled liquid region, the SPS consolidated (Cu sub(0.5)Zr sub(0.5)) sub(100-x)Al sub(x) alloys undergo partial crystallization. The Cu sub(50)Zr sub(50) binary alloy crystallized into CuZr sub(2) and Cu sub(10)Zr sub(7) while the Al-containing alloys crystallized into CuZr sub(2), CuZr and AlCu sub(2)Zr. However, below the glass transition temperature, fcc-Cu nanocrystals formed in the SPS consolidated Cu sub(50)Zr sub(50) alloy. The results showed that the fracture strength and ductility were enhanced due to the precipitation of fcc-Cu nanocrystals. The fracture behavior of the (Cu sub(0.5)Zr sub(0.5)) sub(100-x)Al sub(x) alloys was discussed.