Creep of molybdenum disilicide composites

Abstract The creep deformation behavior of MoSi 2 , MoSi 2 , with SiC and WSi 2 alloy, and the alloy with SiC reinforcement was determined under compression in the temperature range 1100–1450 °C. The effects of reinforcement and alloying were evaluated. Existing theories of composite strengthening were examined in relation to the present results. Models based on creeping matrix with elastically deforming fibers appear to predict the observed behavior better than any other models. Activation energies and volumes were evaluated to identify the creep mechanisms. Based on the stress exponents and the energies, it is concluded that creep progress with increasing temperature and stress from newtonian viscous flow involving diffusion processes to power-law creep involving dislocation climb.

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