Tailoring Thermally Induced Nano-Quasicrystallization and Deformation-Assisted Nanocrystallization for Mechanical Property Improvement in Zr-Al-Ni-Cu-Pd Bulk Metallic Glasses

摘要

The material design tailoring of a synergistic effect of an in-situ nano secondary phase formation and deformation-induced nanocrystallization for improving the mechanical strength and ductility, has been investigated in Zr_(65)Al_(7.5)Ni_(10)Cu_(17.5-x)Pd_x bulk metallic glasses (BMGs). As-cast Zr_(65)Al_(7.5)Ni_(10)Cu_(17.5-x)Pd_x (x = 5-17.5) BMGs have significant ductility in compressive deformation, which is attributed to deformation-induced dynamic nanocrystallization. The 10 at% Pd-containing BMG with a low volume fraction of the quasicrystalline (QC) phase of less than 6% exhibits increases in strength and Young's modulus, in addition to a remaining plasticity of approx 5%, compared with the monolithic glassy alloy. Such improvements in the mechanical properties originate from the combination of two effects of in-situ homogeneous nano-QC formation and deformation-induced inhomogeneous nanocrystallization. The present method should be regarded as a new technique for the production of BMGs with high strength and good ductility.