SiCウィスカ強化6061アルミニウム合金複合材料の押出しによる薄肉管の成形とその機械的性質

抄録

An attempt was made to fabricate thin wall tubes of SiC whisker reinforced 6061 aluminum alloy composite with 1mm thickness, by adopting a hot hydrostatic extrusion. The composite billets were fabricated with a powder metallurgical process and then extruded at a high extrusion ratio. Thin wall tubes with good surface quality, high strength and Young's modulus, and high Weibull modulus were fabricated, through optimization of extrusion conditions such as billet temperature, tool temperature, billet surface roughness and extrusion speed. The billet microstructure was composed of two regions: the high whisker volume fraction region and the whisker-free aluminum alloy region. The extrusion elongated and dispersed the high whisker volume fraction region, resulting in a decrease in the size of this region perpendicular to the extruding direction. The increase in uniformity of whisker dispersion is the major reason for the increase in Weibull modulus, or an improvement in reliability due to extrusion. It was demonstrated that the higher temperature extrusion is a usefull process for fabrication of high quality composite.