Effect of crystal phase on shear bands initiation and propagation behavior in metallic glass matrix composites

The effect of crystal phase structure on the shear bands (SBs) initiation and propagation behavior of Cu₅₀Zr₅₀ metallic glass (MG) matrix composite with a pre-existing crack is studied using molecular dynamics (MD) simulation method. It is found that the crystal diameter has almost no effect on the peak stress of MG-matrix composites, because the change of crystal diameter not only influences the STZ coalesce around the crystal-amorphous interface (CAI) but also affects the magnitude of the repulsive force between CAI and SB. Namely, CAI plays two roles of generating the immature SB and hindering its propagation. The results also indicate that the behavior of SB initiation and propagation shows a stronger dependence on the CAI. Compared with monolithic MGs, the crystal layer changes the propagation path of the SB in the composite. Additionally, we introduce the disorder degree (i.e. entropy) method to analyze the formation process of SBs.