Synthesis and mechanical properties of Zr-Cu-Ni-Ta-Al bulk amorphous alloy matrix composites

Zr-based bulk amorphous alloy (BAA) matrix composites with Ta crystalline phase as reinforcement were prepared by arc-melting copper mold casting method. The effect of Ta element adding on the glass-forming ability and the mechanical properties of (Zr0.65CU0.175Ni0.175)(90-x)Ta-x Al-10(x=0, 4, 6, 8, 10) (at%) alloys were investigated mainly by means of differential scanning calorimeter AA (DSC), X-ray diffraction (XRD) and scanning electric microscopy (SEM). It was shown that the Ta element adding into alloy matrix changed the crystallization behaviors of continuous heating for the alloys. For (Zr0.65Ni0.175CU0.175)(80)Ta10Al10 alloy composite, the solubility limit of Ta in the amorphous phases is approximately 4%. The maximum stress and plastic strain of the composite containing 10% Ta are as high as 1 855 MPa and 3.2%, respectively, both higher than those of the Ta-free BAA. The Ta crystalline particles prevent the catastrophic propagation of the single shear band, favorable for the formation of multiple shear bands, and significantly increasing the plastic strain and yield strength under an uniaxial compression, compared to the Ta-free alloy.