SiC增强铝基复合材料的力学性能

采用半固态搅拌铸造法制备了SiC颗粒增强铝基复合材料,研究了加入不同质量分数SiC和Mg的（Al基体、Al-4 wt.％SiC、Al-4 wt.％高温氧化SiC,Mg的质量分数从0～4 wt.％以1wt.％的含量递增）铝基复合材料的微观结构和力学性能,研究结果表明：经过高温氧化的SiC颗粒能够防止铝液对SiC颗粒的侵蚀,SiC颗粒表面没有发现孔洞.在Al-4 wt.％高温氧化SiC-3 wt.％Mg铝基复合材料中形成了Si和MgAl2O4,其屈服强度、抗拉伸强度和硬度最大,但当Mg的质量分数超过3 wt.％时,其屈服强度和抗拉伸强度降低,这主要是由于过量Mg的加入,会使复合材料中SiC颗粒表面的SiO2与Mg反应后继续与铝液进行反应,这将削弱SiC颗粒与基体的界面结合强度.

Mechanical Properties of SiC-Reinforced Aluminum Matrix Composites

Aluminum matrix composites reinforced with silicon carbide （SIC） particulates were produced by the semi-solid stir-casting method, and the micro-structure and mechanical properties of aluminum matrix composites were researched through the addition of SiC and Mg with different mass fractions （A1 matrix,Ai-4 wt. %SiC and A1-4 wt. % high-temperature-oxidized SiC;Mg with mass fractions increasing from 0 to 4 wt. % by 1 wt. %）. The results showed that high-temperature-oxidized SiC particulates prevented aluminum molten and no holes were foun- ded on the surface of SiC particles under a scanning electron microscope. Si and MgA12 04 formed in Al-4 wt. %-ox- idized SIC-3 wt. %Mg aluminum matrix composites,of which the yield strength, tensile strength and rigidity were maximum,but when the content of Mg exceeded 3wt. %,the yield strength and tensile strength began to decrease because the excessive amount of Mg was added to the composites and the Mg allowed SiO2 in the surface of SiC to react with it and then to continue reacting with aluminum molten, which led to reduction of the interface-bonding strength of SiC particles and matrix.