Deformation behaviors of a Ti-based bulk metallic glass composite in the dendrite softening region

摘要

Deformation behaviors of the Ti_(50)Zr_(20)Nb_(12)Cu_5Be_(13) bulk metallic glass composite in the dendrite softening region have been investigated using uniaxial compressive and tensile tests. All the compressive stress-strain curves show work-hardening phenomenon with the same tendency, the tensile stress-strain curves show work-softening phenomenon. The strain rate sensitivity exponent ranges from 0.061 to 0.072 in the compressive tests, and 0.33 to 0.38 in the tensile tests. The activation volume of the Ti_(50)Zr_(20)Nb_(12)Cu_5Be_(13) bulk metallic glass composite at 710 K ranges from 1.6 nm~3 to 2.5 nm~3 under compressive tests and 1.0 nm~3 to 2.7 nm~3 under tensile tests, indicating that there is a migration of atomic group (about 170-180 atoms) during the deformation. The dendrite of the Ti_(50)Zr_(20)Nb_(12)Cu_5Be_(13) BMGC has been well spheroidized and undergoes severe plasticity deformation after the deformation in the dendrite softening region.