Effect of addition of MgAl₂O₄ on properties of Ti₃SiC₂ matrix composites

Ti₃SiC₂/MgAl₂O₄ composites were fabricated by reactive hot pressing method. The effects of the content of MgAl₂O₄ and hot pressing temperature on the phase constituent, mechanical properties and oxidation resistance of composites were investigated.The results show that hot pressing temperature affects the phase composition of Ti₃SiC₂/MgAl₂O₄ composites and it can get good properties of Ti₃SiC₂/MgAl₂O₄ composite materials in 1 450 ℃. MgAl₂O₄ by introducing the appropriate content has the effect of dispersion strengthening and contributes to improving the mechanical properties of composite materials. When the addition amount is 20wt%, bending strength is 527.6 MPa and fracture toughness is 7.09 MPa·m^1/2. The oxidation resistance of Ti₃SiC₂/MgAl₂O₄ sample is better than pure Ti₃SiC₂. The oxidation layers of Ti₃SiC₂/MgAl₂O₄ composites are composed of two layer at 1 400 ℃, the outer consists of Mg_0.6Al_0.8Ti_1.6O₅ solid solution and rutile of TiO₂, and the inner is a mixture of TiO₂, cristobalite and a small amount of unoxidized matrix.