Effect of minor Nb addition on mechanical properties of in-situ Cu-based bulk metallic glass composite
(State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China)
Abstract: In-situ formed (Cu0.6Zr0.3Ti0.1)95Nb5 bulk metallic glass (BMG) composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present (Cu0.6Zr0.3Ti0.1)95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.
Key words: bulk metallic glass composite; Nb addition; shear band; microstructure; mechanical property