ZrCu-based metallic glass matrix composites with Ta dispersoid by in situ dealloying method

Abstract

Zr48Cu36Al8Ag8-based bulk metallic glass matrix composites (BMGCs) with in situ dispersed Ta-rich particles surrounded by microcrystalline phases were fabricated successfully by both the conventional arc melting and a new dealloying methods followed by copper mold casting. The microstructures and uniaxial compressive mechanical properties of as-cast φ3-mm rods fabricated by the two different methods were compared. The size and dispersion of the Ta-rich particles and the mechanical properties of the as-cast BMGC rods obtained using the new dealloying method were smaller, finer and better than those of the rods obtained using the conventional arc-melting method. Both the compressive and tensile plastic strain increased from almost 0% for monolithic Zr48Cu 36Al8Ag8 bulk metallic glass to about 7 and 1%, respectively, for as-cast BMGC rods with 5 at% Ta formed by the in situ dealloying method. These in situ Ta-rich particles are considered as obstacles that restrict shear band propagation. An obvious work-hardening phenomenon can be observed in compression tests considerably due to work hardening of the Ta-rich particles restricted by the surrounding microcrystals. © 2013 The Japan Institute of Metals and Materials.