Formation of Cu–Zr–Al–Er bulk metallic glass composites with enhanced deformability

Based on thermal stability investigations, a new parameter has been introduced in order to evaluate the formation tendency of different sized CuZr-based metastable alloys with the precipitation of B2 CuZr [26]. To verify our prediction further, a Cu46.25Zr44.25Al7.5Er2 alloy was prepared and its bulk metallic glass composites (BMGCs) with larger dimensions containing B2 CuZr precipitates were successfully fabricated by rapid quenching method. The composites exhibit macroscopically detectable compressive plastic strain and obvious work hardening, resulting from a deformation-induced martensitic transformation and the multiplication of shear bands. The plastic deformability of Cu46.25Zr44.25Al7.5Er2 BMGCs is relatively lower than that of Cu42.5Zr42.5Al5 BMGCs, most probably due to the intrinsic brittleness of Cu46.25Zr44.25Al7.5Er2 metastable alloys and/or the inhomogeneous distribution of B2 CuZr in the amorphous matrix.