Sicウイスカー強化Al合金複合材料の機械的性質に及ぼすHIP固化成形温度の影響

抄録

The effects of consolidating temperature on the strength, impact value, microstructure and fractograph of SiC whisker reinforced 6061 (1%Mg) and 5056 (5%Mg) composites were studied. The composites were fabricated with a powder metallurgical method using HIP. The optimum consolidating temperature was 625°C (semi-liquid region) for the 6061 composite and 500°C (solid region) for the 5056 composite. The quantitative analysis of Al₄C₃ using gas chromatography showed that the extent of the reaction between SiC whisker and Al was accelerated by the increase of Mg in the Al alloy. An examination of X-ray diffraction, SEM and EPMA revealed that in addition to Al₄C₃, the reaction produced Si in the 6061 composite and Mg₂Si in the 5056 composite. The degradation of strength and impact value at a higher consolidating temperature was considered to be due to the presence of such coarse reaction products as Mg₂Si and Si, coarse Al-Fe (Cr, Mn)-Si precipitates and the decrease of the Mg solution content in the Al rather than because of the decrease of interfacial bonding strength and the damage of SiC whiskers.