Investigation of toughening and resistance-curve behavior in hybrid molybdenum disilicide

This paper presents the results of a study of the toughening and resist-curve behavior in a hybrid molybdenum disilicide (MoSi₂) composite that has been reinforced with 2 mol% yttria partially stabilized zirconia particles (TZ-2Y) and niobium layers. Toughening and resistance-curve behavior occur as a result of the combined effects of crack bridging and transformation toughening. Crack-tip shielding that is due to large-scale crack bridging and transformation toughening also is modeled using micromechanics concepts. The models show that the overall crack-tip shielding from transformation toughening is very limited. However, large-scale bridging by the ductile niobium layers promotes significant levels of toughening and resistance-curve behavior.