Numerical study on toughening mechanism of bulk metallic glass composites from martensite transformation of toughening phase

Abstract Numerical simulation was conducted to investigate the toughening mechanisms of bulk metallic glass composites (BMGCs) originated from the martensite transformation of toughening phase (TP). Firstly, a free volume model was chosen to describe the deformation of BMG matrix by addressing the initiation and propagation of shear bands (SBs) in BMG matrix; while a macroscopic phenomenological constitutive model was employed to describe the martensite transformation of TP and its correspondent deformation. Then the two models were implemented into ABAQUS as user material subroutines (UMATs). Finally, the numerically simulated stress-strain curves of BMGCs were compared with the experimental ones to verify the effectiveness of finite element model, and then some numerical analyses were performed to discuss the toughening mechanism of BMGCs caused by the martensite transformation of TP. It is found that the strain hardening and SBs' evolution in BMGCs were significantly influenced by the transformation strain, start stress and hardening modulus of martensite transformation. The excellent toughness of BMGCs mainly results from the phase transition from austenite to martensite phase in TPs.