Toughening and strengthening of ceramics reinforced by dilatant transformations and ductile particles

This theoretical study considers the toughening and strengthening of brittle ceramic matrices reinforced by both dilatant phase-transforming particles and ductile crack-bridging particles. Nondimensional toughnesses are calculated as a function of the growth of “long”, dominant precut cracks, and nondimensional strengths are calculated as a function of the growth of pre-existing finite cracks. The presence of the dilatant transformations results in peak toughnesses and peak strengths for finite amounts of crack growth. For certain parametric combinations of reinforcements, synergistic interactions may result in peak toughness and strength ratios that exceed substantially the corresponding levels due to the “uncoupled” (i.e. isolated) mechanisms.