Double toughening Ti-based bulk metallic glass composite with high toughness, strength and tensile ductility via phase engineering

Abstract

The popular strategy of overcoming the brittle fracture of bulk metallic glasses (BMGs) is to develop BMG composites (BMGCs). Most BMGCs consist of a single crystalline phase and glassy phase, and they display enhanced plasticities. However, these BMGCs usually display a trade-off in strength, ductility and fracture toughness as most engineering structural materials, which severely hampers their industrial application. To obtain a pronounced combination in tensile strength, tensile ductility and fracture toughness, the multiphase reinforced dispersive Ti-based BMG composite was successfully prepared via phase engineering. The as-prepared BMGC consists of β-phase, α-phase and glassy phase. The composite manifested the tensile mechanical properties with the yield strength of ~ 1410 MPa, ultimate tensile strength of ~ 1625 MPa, and tensile ductility of ~ 3.6%, and fracture toughness of ~ 110 MPa∙m1/2. The outstanding tensile properties are attributed to the double toughening of α-phase and β-phase. The high fracture toughness is ascribed to that the coarser dual crystalline phases lead to the devious crack propagation and crack bridging. Our work highlights a novel route for developing high-performance BMGCs.