Simultaneous enhancement of tensile properties and fracture toughness of bulk metallic glass composites

TY Yan and L Zhang and XD Yuan and B Li and JH Bai and HM Fu and HW Zhang and HF Zhang, ACTA MATERIALIA, 291, 121018 (2025).

DOI: 10.1016/j.actamat.2025.121018

Crystalline materials with high strength and large tensile ductility generally exhibit high fracture toughness. However, although bulk metallic glass composites (BMGCs) exhibit a much-improved combination of strength and ductility than bulk metallic glasses (BMGs), their fracture toughness is often much lower. Moreover, the deformation mechanisms of BMGCs under uniaxial tensile stress and complex stress during fracture toughness measurement remain largely elusive. Here, the tensile properties and fracture toughness of the Ti-based BMGCs containing stable crystals or phase-transformable crystals are investigated. The phase-transformable BMGCs exhibit much improved tensile properties but a lower fracture toughness than the BMGCs with stable crystals, contradictory to the common perception that is prevalent for crystalline materials. It is revealed that the deformation mechanisms in the glass- crystal dual-phase BMGCs are sensitive to the state of stress. While a significant fraction of the deformation-induced martensite and plasticity through shear bands in phase-transformable BMGCs occurs under uniaxial tension, it is suppressed due to the stress triaxiality at the crack tip during fracture toughness measurement, resulting in lower fracture toughness. Based on the findings, a strategy that relies on tuning the phase metastability of the crystalline phase is proposed and experimentally validated. The tensile properties and fracture toughness of the newly designed BMGC are simultaneously enhanced, superior to all the reported BMGCs.

Return to Publications page