Reduction of shear localization through structural rejuvenation in Zr–Cu–Al bulk metallic glass

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 765; no. C; p. 138304
• Main Authors: Meng, F., Tsuchiya, K., Kramer, M.J., Ott, R.T.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 23.09.2019; Elsevier BV; Elsevier
• Subjects: Aluminum; Amorphous materials; Bulk density; Copper; Density measurement; Distribution functions; Elastic deformation; Energy measurement; Enthalpy; Localization; Mechanical properties; Metallic glass; Metallic glasses; Modulus of elasticity; Nanoindentation; Pair distribution function; Plastic deformation; Pressure effects; Severe plastic deformation; Shear localization; Strain rate; Structural rejuvenation; X-ray scattering; Severe plastic deformation; Structural rejuvenation; Pair distribution function; Metallic glass; Nanoindentation
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.138304

The effect of high-pressure torsion (HPT) on the structure and mechanical behavior of Zr50Cu40Al10 bulk metallic glass was investigated using calorimetry, density measurement, high-energy X-ray scattering and nanoindentation. Increase in rotation number, and thus plastic deformation, lowers the hardness and elastic modulus, as well as the critical strain rate for suppressing the shear localization. Strain-softening induced by plastic deformation is attributed to the structural rejuvenation. Wide-angle X-ray scattering (WAXS) measurements suggest that HPT deformation reduces and broadens the peaks in the pair distribution function indicative of pronounced structural disordering and enabling structural rejuvenation. Measured excess free volume of 0.8% for samples deformed by HPT with a maximum structural relaxation enthalpy of 29.5 J/g in the sample with 20 and 50 revolutions.