Structure and Wear Properties of Sic Reinforced Al-Li (8090) Alloy in the Cast and Heat Treated Conditions

Abstract

Different percentages of SiC particulates (0-15 wt%) were introduced into Al-Li (8090) to produce composite by using the vortex technique. Microstructural studies of both Al-Li and Al-Li composites were carried out in the cast and heat treated conditions. The results showed that the cast composite obtained some degree of porosity especially with a high volume fraction (15% of SiC) particulates. The examination of SiC reinforced alloys in the cast and heat treated conditions showed an increasing grain refining effect compared to the Al-Li base alloy. As the volume fraction of SiC particulates increased from 5 to 15% the hardness also increased from 68 to 108 HB in the cast condition and from 90 to 120 HB in the peak aged condition. This increase in hardness was related to the modified structure and the hard dispersed SiC particulates. Mechanical deformation of 50% reduction in thickness by rolling was applied to the investigated alloys to study its effect on impact strength and wear properties. Dry sliding wear test was performed on both cast and peak aged conditions. The deformed alloys showed better wear results than the cast ones due to the strain hardening occurred during the rolling process. The minimum wear rate was obtained at 10% SiC in both cast and heat treated conditions.