Design novel Ti-based metallic glass matrix composites with excellent dynamic plasticity

A novel light-weight and high-toughness in-situ dendrite/metallic glass matrix composites (MGMCs) with a composition of Ti58Zr12Ni6Ta13Be11 was designed. Quasi-static and dynamic compressive properties of MGMCs were investigated. The alloys showed excellent compressive properties of the maximum strength over 1.6 GPa and the total strain over 10% under the quasi-static loading. Under dynamic compressive loading, the compressive strength increased up to 1.9 GPa, whereas the total strain is nearly undiminished exhibited favourable plastic deformation. Deformation mechanisms related to the improvement of strength and ductility were investigated thoroughly by focusing on how ductile dendrites affected the initiation and propagation of deformation bands, accompanied with the localization of deformed bands and effects of ω phase precipitation, shear slipping, thermo softening, and melting. A constitutive relationship is obtained by modified Johnson-Cook plasticity model, which is applied to model the dynamic flow stress behavior. In addition, under dynamic compression, the strain rate effect of the yielding strength exerts distinctly positive strain rate sensitivity (SRS), which can be attributed to the dendrite-dominated plastic deformation fracture mechanism related to the significant accommodation of deformed bands and dislocation in the dendrites to the macroscopic dynamic deformation at relative strain rates.