Al6Si2O13晶须和TiC颗粒复合强化多孔Al2TiO5基复合材料

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

  • 摘要: 以γ-AlOOH和TiO2为原料,添加不同质量分数SiC晶须(SiCw),采用无压反应烧结法制备多孔(Al6Si2O13+TiC)/Al2TiO5复合材料,分析了SiCw质量分数对(Al6Si2O13+TiC)/Al2TiO5复合材料孔隙率和抗压强度的影响,讨论了SiCw的强化机制。结果表明:不添加SiCw时,产物主要为Al2TiO5和少量Al2O3,还有少量未反应的TiO2;加入SiCw之后,还形成了Al6Si2O13和TiC相,TiC和Al6Si2O13分别以规则颗粒状和晶须形态存在于Al2TiO5基体中。TiC颗粒与Al6Si2O13晶须通过细化显微组织、裂纹偏转和晶须桥连机制,起到协同强化作用。SiCw的添加使孔隙率和抗压强度同时大幅度提高,随着SiCw质量分数的增加,(Al6Si2O13+TiC)/Al2TiO5复合材料孔隙率降低,抗压强度提高的速率减小,当SiCw的质量分数为7.2%时,抗压强度最高,达到301.81 MPa。

     

    Abstract: 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 (SiCw). The effect of SiCw mass fraction on the porosity and compressive strength of (Al6Si2O13+TiC)/Al2TiO5 composites was analyzed, and the strengthening mechanism of SiCw was discussed. The results show that, the product without SiCw is composed of Al2TiO5, a small amount of Al2O3, and a few of unreacted TiO2. After adding SiCw, 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 SiCw. With the increasing of SiCw mass fraction, the porosity of (Al6Si2O13+TiC)/Al2TiO5 composites decreases, but the increasing rate of compressive strength slows down gradually. When SiCw mass fraction is 7.2%, the compressive strength is highest, which can reach 301.81 MPa.

     

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