Effect of cooling rate on the volume fraction of B2 phases in a CuZrAlCo metallic glass matrix composite

The material properties of bulk metallic glass matrix composites (BMGMCs) depend strongly on the morphology and elastic constants of the included crystalline phase. Transformation induced plasticity (TRIP) BMGMCs based on the Cu-Zr system are alternatives to traditional dendrite-reinforced BMGMCs. Samples of a representative alloy, Zr48Cu47.5Al4Co0.5, are fabricated in various dimensions and characterized using DSC, SEM, and ultrasonic measurement of elastic constants. It is shown that the Cu-Zr system uniquely softens during crystallization, and the microstructure of the alloy depends strongly on the rate of cooling. We conclude by discussing how combinations of part design and alloy development could be used to utilize these alloys in applications.