高温空气氧化对高硅铝合金材料组织及物理性能的影响  

Effect of high-temperature air oxidation on microstructure and physical properties of high-silicon aluminum alloy

作　　者：杨伏良[1] 易丹青[1] 张伟[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《中国有色金属学报》2008年第2期317-322,共6页The Chinese Journal of Nonferrous Metals

基　　金：国防科学技术工业委员会资助项目(2003-151)

摘　　要：采用高温空气氧化对Al-12Si与Al-30Si合金粉末进行预处理,结合包套热挤压,制备出Al2O3与SiO2增强的弥散强化型铝硅复合材料,通过金相及热物性测试,对材料显微组织、密度、气密性、热膨胀系数、导热系数进行了分析。结果表明:合金粉末经高温空气氧化预处理后,Al-12Si晶粒长大不明显,而Al-30Si晶粒发生了明显长大;材料致密度随氧化时间延长略有下降,但均在97%以上,材料气密性均在1×10-9 Pa.m3/s左右;在相同工艺条件下,Al-30Si材料热膨胀系数明显低于Al-12Si材料,氧化时间对材料热膨胀系数影响不明显;导热系数随材料中硅含量增加而下降,随粉末氧化时间延长而增加,氧化24 h后,材料导热系数超过120 W/(m.K)。The high-temperature air oxidation pretreatment process was applied to Al-12Si and Al-30Si alloy powders, and combined with hot-extrusion to fabricate SiO2 and Al2O3 dispersion strengthening composites. Optical microscopy and thermal physical testers analyzed the microstructure, density, hermeticity, coefficient of thermal expansion and thermal conductivity. The results show that： After powders oxidation, growth of Si grains in Al-30Si is more obvious than that of Al-12Si; the relative density of materials decreases with the increasing of oxidation time, but they are all higher than 97%. The hermeticity is about 1 × 10^-9 Pa·m^3/s. Under the same process condition, the coefficient of thermal expansion of Al-30Si is much lower than that of Al-12Si, and the effect of oxidation time on coefficient of thermal expansion is not obvious. The thermal conductivity decreases with increase of Si content and increases with prolonging oxidation time, after oxidation 24 h, it exceeds 120 W/（m·K）.

关 键 词：高硅铝合金 高温空气氧化 热膨胀系数 导热系数 

分 类 号：TF112[冶金工程—冶金物理化学] TG337[金属学及工艺—金属压力加工]