Formation of bulk metallic glass in situ composites in Cu₅₀Zr₄₅Ti₅ alloy

The structure and mechanical property of the Cu₅₀Zr₄₅Ti₅ bulk metallic glass in situ composites prepared by copper mold casting are investigated. It was found that nanocrystals with the sizes ranging from 2 to 10 nm distributed homogeneously in the glassy matrix for the Cu₅₀Zr₄₅Ti₅ rod with a diameter of 1.5 mm. The 2.5 mm Cu₅₀Zr₄₅Ti₅ rod is a kind of gradient composite, consisting of crystalline phase in the central part and glassy phase in the outer part. The yield strength and elastic-plastic strain for the 1.5 mm Cu₅₀Zr₄₅Ti₅ rod are 1680 MPa and 10.6%, respectively. For the 2.5 mm Cu₅₀Zr₄₅Ti₅ rod, the yield strength and elastic-plastic strain are 1020 MPa and 18% coupled with evident work hardening behavior. The ZrCu phase precipitated from the Cu₅₀Zr₄₅Ti₅ rod shows evident plastic deformation, which contributes to the high ductility of the Cu₅₀Zr₄₅Ti₅ bulk metallic glass in situ composites.