Mechanical properties of an aluminum composite reinforced with alumina microspheres

Experiments were conducted to compare the behavior of an Al-6061 metal matrix composite, reinforced with approx.20 volume % of alumina-based microspheres, with the unreinforced monolithic alloy. The results show that, from measurements of the 0.2% proof stress, there is no evidence for any significant acceleration in the aging process in the composite material. The 0.2% proof stress decreases with increasing temperature at a faster rate in the composite so that the monolithic alloy exhibits higher yield stresses at the highest testing temperatures. Under creep conditions of constant stress at high temperatures, the composite exhibits a higher creep strength and higher values for the stress exponents for creep.