Application of Spinodal Decomposition to Produce Metallic Glass Matrix Composite with Simultaneous Improvement of Strength and Plasticity

An original two-step procedure, based on the miscibility gap between two elements, produced an in-situ bulk metallic glass matrix composite. The Zr-Ta binary alloy, which exhibits a large immiscible region in solid state, formed a two-phase mixture of Zr- and Ta-rich solid solution by phase separation. When the Zr-Ta binary alloy was remelted with Cu, Zr, and Ti, the Ta-rich solid solution, which has a high melting temperature, did not melt, while the remaining melt containing Zr-rich solid solution mixed with the other elements and solidified into an amorphous phase at lower temperatures. The improvement of strength in the composite indicates that the interfaces between the Ta-rich particles and the BMG matrix formed by phase separation are strong enough to hold a high interfacial cohesion strength.