镁含量对无压浸渗SiC/Al复合材料性能的影响

Effect of Mg Content on Properties of SiC/Al Composites Prepared by Pressureless Infiltration

以SiC粉及铝合金(3%Mg(质量分数)、5%Mg、7%Mg、10%Mg)为主要原料,采用无压浸渗工艺制备得到了SiC/Al复合材料。表征了SiC/Al复合材料的物相组成、显微结构、力学性能及热导率,研究了合金中Mg含量对SiC/Al复合材料结构组成、力学及热学性能的影响。结果表明:制备得到的SiC/Al复合材料主晶相均为SiC与Al。适量Mg的引入有助于改善铝合金与SiC颗粒间的浸渗性能,能有效促进SiC/Al复合材料的界面反应。其中引入5%Mg样品的显微结构较为致密,综合性能较优,其气孔率为0.13%,体积密度为2.94 g/cm3,抗弯强度为(366.36±14.37)MPa,断裂韧性为(9.2±0.27)MPa·m1/2,热导率为178.81 W/(m·K)。

SiC/Al composites were prepared by a pressureless infiltration process using SiC powder and aluminum alloy(3%Mg(in mass fraction),5%Mg,7%Mg,and 10%Mg)as main raw materials.The phase composition,microstructure,mechanical properties and thermal properties of SiC/Al composites were characterized.The effect of Mg content in aluminum alloy on the phase composition,microstructure,mechanical properties and thermal properties of SiC/Al composites was investigated.The results show that Mg can improve the impregnation properties of aluminum alloys and promote the occurrence of interfacial reaction in SiC/Al composites.The main crystalline phases of the prepared SiC/Al composites are both SiC and Al.The presence of Si,Mg2Si and MgAl2O4 phases is also detected.After comparison,the sample with 5%Mg performs the better properties.The optimum performance of the sample prepared with 5%Mg(i.e.,flexural strength of(366.36±14.37))MPa,fracture toughness of(9.2±0.27)MPa·m1/2 and thermal conductivity of 178.81 W/(m·K)can be obtained when the porosity is 0.13%and the bulk density is 2.94 g/cm3.