Effect of Interfacial Shear Strength on Impact Properties of Nb/MoSi2 Laminate Composites

The relationship between the interfacial shear strength and the impact properties of Nb/MoSi2 laminate composites have been investigated, in conjunction with the evaluation of their fracture strain and the thickness of interfacial reaction layer. Nb/MoSi2 laminate composites have been fabricated by stacking sintered MoSi2 sheets and Nb sheets, alternately and hot pressing in the griphite mould. The instrumented Charpy impact test, the interfacial shear test and the tensile test was carried out at the room temperature. To change the interfacial shear strength associated with the thickness of interfacial reaction layer, Nb/MoSi2 laminate composites were fabricated as the parameter of hot press temperature. It is found that the interfacial shear strength between MoSi2 and Nb increases with the growth of the interfacial reaction layer, which results from the increase of fabricating temperature. Such a increase of the interfacial shear strength leads to a localized deformation of Nb foil and then deteriorates the enhancement of impact value in Nb/MoSi2 laminate composites. There is obviously an appropriate interfacial shear strength capable of maximizing the impact value in this composite system, associated with the plastic deformation of Nb foil.