Al₆Si₂O₁₃ whiskers and TiC particles co-strengthing porous Al₂TiO₅ matrix composites

Porous (Al₆Si₂O₁₃+TiC)/Al₂TiO₅ composites were fabricated by pressless reaction sintering method with γ-AlOOH, TiO₂ as raw materials and adding different mass fractions of SiC whiskers (SiC_w). The effect of SiC_w mass fraction on the porosity and compressive strength of (Al₆Si₂O₁₃+TiC)/Al₂TiO₅ composites was analyzed, and the strengthening mechanism of SiC_w was discussed. The results show that, the product without SiC_w is composed of Al₂TiO₅, a small amount of Al₂O₃, and a few of unreacted TiO₂. After adding SiC_w, Al₆Si₂O₁₃ and TiC phases are formed. Moreover, TiC and Al₆Si₂O₁₃ exist in Al₂TiO₅ matrix mainly with regularly particles and whiskers morphology respectively. TiC particles and Al₆Si₂O₁₃ whiskers synergeticly reinforce composites by refining the microstructure, crack deflecting and whiskers bridging effects. Both porosity and compressive strength improve with the addition of SiC_w. With the increasing of SiC_w mass fraction, the porosity of (Al₆Si₂O₁₃+TiC)/Al₂TiO₅ composites decreases, but the increasing rate of compressive strength slows down gradually. When SiC_w mass fraction is 7.2%, the compressive strength is highest, which can reach 301.81 MPa.