Relationship between Deformation and Crystallization in Zr_(60)Al_(15)Ni_(25) and Zr_(60)Al_(15)Cu_(27.5) Metallic Glass

摘要

Deformation behavior of a supercooled liquid region in melt-spun Zr_(60)Al_(15)Ni_(25) and Zr_(65)Al_(7.5)Cu_(27.5) metallic glass was investigated. The viscous flow behavior is very sensitive to the strain rate and the size of crystalline precipitates, which can be classified into 4 types based on shape of the stress-strain curve: stress overshoot mode, stable viscous flow mode with constant flow stress, strain hardening mode and strain softening mode. The strain hardening and strain softening are due to the crystalline phase distribution in supercooled liquid. The strain hardening mode was observed in Zr_(60)Al_(15)Ni_(25), while Zr_(65)Al_(7.5)Cu_(27.5) deformed with strain softening mode rather than strain hardening mode. Tensile deformation enhanced thermal crystallization in a supercooled liquid region was observed in Zr_(60)Al_(15)Ni_(25).