Multiple Shear Band Initiation of Metallic Glass in Composites

Multiple shear banding is observed in metallic glasses during tensile deformation of laminated composites containing such glasses. The phenomenon is related to (1) the local stress concentration that develops as a result of the formation of the first shear band, (2) the distribution in stress required to initiate shear banding in tensile loading, and (3) the properties of the surrounding matrix. The tendency for localized and uniform multiple shear banding has been determined. This was done by utilizing a finite element method (FEM) to simulate the local stress state in the vicinity of the shear band first formed, and by determining the distribution in shear band initiation strengths. The experimental data were combined with the FEM analysis to "predict" locations of secondary shear band initiation. Localized secondary banding is predicted for large initial slip displacements, whereas uniform banding is expected when the initial slip displacement is small.