Inhomogeneous deformation in bulk metallic glasses: FEM analysis

A modified coupled thermo-mechanical 3D constitutive model for bulk metallic glasses (BMGs), which integrates all the effects of free volume, temperature and hydrostatic stress on the deformation and failure of material, is introduced and implemented into LS-DYNA commercial software. With considering the inhomogeneity of the microstructure of BMGs, FEM geometrical model of the randomly distributed shear-band zones in the material is established. Then FEM simulations for different deformation scenarios, including quasi-static tension, compression, and bending as well as instrumented anvil-on-rod impact, are conducted, and the corresponding deformation and failure mechanisms of BMGs is analyzed. The inhomogeneous deformation in BMGs, especially the shear banding behaviors, including the nucleation and propagation of shear bands, and the shear banding-induced failure, is discussed in detail. Related analysis shows that BMGs exhibit a significant inhomogeneous deformation at the room temperature, and the corresponding mechanical behaviors are affected by the hydrostatic stress. The constitutive model combined with the geometrical models which contain the shear-band zones could represent the deformation and failure characteristics of BMGs relatively well.