Fabrication and fracture analysis of MoSi2 matrix composites by mechanical alloying

摘要

Four composites, MoSi2+ZrO2, MoSi2+ZrO2(Y2O3), MoSi2+ZrO2+SiC and MoSi2+ZrO2(Y2O3) +SiC are fabricated by mechanical alloying. It is clear that cracks produced on the MoSi2 matrix composites during hardness testing belong to the Palmquist crack system. The value of highest fracture toughness of MoSi2+ZrO2+SiC composite is 7.58 MPa· m1/2, which is nearly three times that of monolithic MoSi2. This can be attributed to well-distributed ZrO2 and SiC particles along the boundaries of very fine MoSi2 grains.