The influence of oxidation on crack resistance in injection moulded Cr3C2/Al2O3 composites

The crack resistance (R-curve) of injection moulded Cr3C2/Al2O3 composite was studied using the indentation-strength-in-bending technique. The influence of heat treatment on the crack resistance was investigated. The oxidation layer containing alumina and alumina/chromia solid solution was in a compression of −179 and −195 MPa as evaluated by X-ray analysis and indentation method, respectively. The results were slightly different from the thermal mismatch calculation (−139 MPa). The relatively compressive, low porous oxidation layer caused significant increase in crack resistance. Crack healing could contribute also partially to crack resistance.