(中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 采用光學(xué)顯微鏡、X射線衍射儀和電子萬能試驗(yàn)機(jī)等手段研究Mg含量對真空壓力浸滲SiCp/Al復(fù)合材料組織和性能的影響。結(jié)果表明:Mg能提高Al合金的浸滲性能，Mg含量的增加使復(fù)合材料致密度升高。Mg促進(jìn)SiC/Al界面反應(yīng)的發(fā)生，當(dāng)Mg含量為0~6%(質(zhì)量分?jǐn)?shù))時(shí)，未觀察到明顯界面反應(yīng)產(chǎn)物；當(dāng)Mg含量為8%時(shí)，發(fā)生界面反應(yīng)生成Mg2Si和Al4C3。當(dāng)Mg含量為0~6%時(shí)，由于復(fù)合材料致密度的提高及Mg對Al基體的固溶強(qiáng)化作用，導(dǎo)致復(fù)合材料強(qiáng)度提高；當(dāng)Mg含量為8%時(shí)，生成的Al4C3降低SiC/Al界面結(jié)合力，使復(fù)合材料強(qiáng)度下降。當(dāng)Mg含量為0~4%時(shí)，致密度的提高使復(fù)合材料熱導(dǎo)率上升；當(dāng)Mg含量為4%~8%時(shí)，過量的Mg使Al基體熱導(dǎo)率降低，Al4C3的生成使界面熱傳導(dǎo)受阻，導(dǎo)致復(fù)合材料熱導(dǎo)率下降。
關(guān)鍵字: SiCp/Al復(fù)合材料；真空壓力浸滲；顯微組織；物相；力學(xué)性能；熱導(dǎo)率
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effect of Mg content on the microstructures and properties of SiCp/Al composites prepared by vacuum pressure infiltration was investigated by optical microscopy, X-ray diffractometer and electronic universal testing machine. The results reveal that the addition of Mg enhances the infiltration ability of Al matrix, leading to the increase of relative densities of composites. The addition of Mg promotes the SiC/Al interface reactions, no obvious reaction products are observed when Mg content is 0-6% (mass fraction), while both Mg2Si and Al4C3 form at Mg content of 8%. The strength of composites increases with the increasing content of Mg when Mg content is among 0-6%, due to the increase of relative densities and strengthening of Al matrix by solid solution hardening. When Mg content is 8%, the formation of Al4C3 leads to the decrease the bonding strength of SiC/Al interfaces, undermining the bonding strength of composites. The thermal conductivity of composites increases with the increasing Mg content when Mg content is 0-4%, because of the increases of relative densities. When Mg content is 4-8%, the thermal conductivity of composites decreases as Mg content increases. It is explained by the combined action of excessive Mg undermining the thermal conductivity of Al matrix and Al4C3 weakening the heat transfer of interfaces.
Key words: SiCp/Al composite; vacuum pressure infiltration; microstructure; phase; mechanical property; thermal conductivity
