Contributions of atomic diffusion and plastic deformation to the diffusion bonding of metallic glass to crystalline aluminum alloy

A mathematical model was established to estimate the contributions of different mechanisms to the diffusion bonding of Zr-based bulk metallic glass to crystalline aluminum alloy. Additionally, the fraction of contact area with oxide film ϕ was introduced into the model since oxide film is the main barrier to atomic bonding across interface at lower temperature. The model calculation displayed that the plastic deformation of Al alloy dominated the void formation stage, while the homogeneous plastic flow of BMG played a major role in the void shrinkage stage. The joints bonded by two different methods were used to verify the model. The experimental strength of joints achieved by pre-friction assisted diffusion bonding and Ar ion assisted diffusion bonding had a sound fit with the theoretical strength curves of ϕ = 28% and 22.5%, respectively.

► A model was established to describe the diffusion bonding of dissimilar materials.
► A parameter ϕ denoting surface state was introduced into the theoretical model.
► The experimental strength of joints had a sound fit with the theoretical calculation.