Quasi-static and dynamic response of explosively consolidated metal-aluminum powder mixtures

Nearly fully dense (>96% theoretical maximum density) powder mixture compacts with combinations of Nb, Ni, Mo, W, and Ta, with Al, were produced by explosive consolidation. The quasi-static and dynamic behavior and failure mechanisms were investigated experimentally and computationally. For two mixtures (Ni + Al, W + Al) the Al phase was continuous, while for the other three mixtures (Nb + Al, Ta + Al, Mo + Al), the Al phase was discontinuous. It was found that the continuous phase significantly influenced the mechanical response (in compression) and determined the fracture morphology of the compacts. Accordingly, the mixtures with continuous Al phases had the lowest compressive strength. Two distinct failure mechanisms, axial splitting and shear failure, were observed. Axial splitting occurred when the Al phase was continuous (Ni + Al, W + Al); shear failure was primarily associated with extensive deformation of the Nb, Ta and Mo continuous phases. Finite element simulations provide valuable help in interpreting the experimental results and predicting mechanical strength and failure mechanisms akin to those observed. The interfacial bonding strength is shown to be an important parameter in determining the mechanical response of the compacts.