Al_6Si_2O_(13)晶须和TiC颗粒复合强化多孔Al_2TiO_5基复合材料

以γ-AlOOH和TiO_2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(Al_6Si_2O_(13)+TiC)/Al_2TiO_5复合材料,分析了SiCw质量分数对(Al_6Si_2O_(13)+TiC)/Al_2TiO_5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Al_2TiO_5和少量Al_2O_3,还有少量未反应的TiO_2;加入SiCw之后,还形成了Al_6Si_2O_(13)和TiC相,TiC和Al_6Si_2O_(13)分别以规则颗粒状和晶须形态存在于Al_2TiO_5基体中。TiC颗粒与Al_6Si_2O_(13)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,(Al_6Si_2O_(13)+TiC)/Al_2TiO_5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。

Al6 Si2 O13 whiskers and TiC particles co-strengthing porous Al2 TiO5 matrix composites

Porous (Al6 Si2 O13+TiC)/Al2 TiO5 composites were fabricated by pressless reaction sintering method withγ-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 (Al6 Si2 O13+TiC)/Al2 TiO5 composites was ana-lyzed,and the strengthening mechanism of SiCw was discussed.The results show that,the product without SiCw is composed of Al2 TiO5 ,a small amount of Al2 O3 ,and a few of unreacted TiO2 .After adding SiCw ,Al6 Si2 O13 and TiC phases are formed.Moreover,TiC and Al6 Si2 O13 exist in Al2 TiO5 matrix mainly with regularly particles and whiskers morphology respectively.TiC particles and Al6 Si2 O13 whiskers synergeticly reinforce composites by refi-ning the microstructure,crack deflecting and whiskers bridging effects.Both porosity and compressive strength im-prove with the addition of SiCw .With the increasing of SiCw mass fraction,the porosity of (Al6 Si2 O13 +TiC)/Al2 TiO5 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.