Plastic deformation of single crystals of (Mo1−XWX)Si2 with the C11b structure

The deformation behavior of single crystals of MoSi2–WSi2 solid-solutions with the C11b structure has been investigated as a function of alloy composition in the temperature range from room temperature to 1500°C in compression, paying special attention to the contribution of stacking faults on (001) whose density increases with the increase in WSi2 additions. The strength of MoSi2 increases with the increase in WSi2 additions, in particular, at high temperatures but the onset temperature for plastic flow decreases rather rapidly with the increase in the amount of WSi2 additions. The improvement of fracture toughness of MoSi2 is found to be difficult to be achieved simply by forming solid-solutions with WSi2 because of the rather rapid decrease in the deformability and the gradual increase in the density of (001) stacking faults with the increase in WSi2 additions.