Effect of Fabricating Temperature and Volume Fraction of Nb Sheet on Impact Properties of Nb/MoSi2-ZrO2 Laminate Composites

Nb/MoSi2-ZrO2 laminate composites have been successfully fabricated by alternately stacking MoSi2-ZrO2 powder layer and Nb sheet, followed by hot pressing in a graphite mould. The selected fabricating parameters were hot press temperature and volume fraction of Nb sheet. The instrumented Charpy impact test was carried out at the room temperature in order to investigate the relationship between impact properties and fabricating conditions. The interfacial shear strength between MoSi2-ZrO2 and Nb, which is associated with the fabricating temperature and the growth of interfacial reaction layer, is also discussed. The plastic deformation of Nb sheet and the interfacial delamination were macroscopically observed. The Nb/MoSi2-ZrO2 laminate composites had the maximum impact value when fabricated at 1623 K, accompanying the increase of fracture displacement and crack propagation energy. The impact value of Nb/MoSi2-ZrO2 laminate composites dramatically increased with increasing the volume fraction of Nb sheet and showed 64.9 kJ/m2 for Nb content of 15 vol%. The interfacial shear strength of Nb/MoSi2-ZrO2 laminate composites increased with the growth of interfacial reaction layer, which resulted from the increase of fabricating temperature. It is useful to promote an appropriate interfacial shear strength for the enhancement of impact value of Nb/MoSi2-ZrO2 laminate composites. A large increase of interfacial shear strength restrains the plastic deformation of Nb sheet.