Effect of solution treatment temperature on tensile properties of AI-7Si-O.3Mg (wt-%) alloy

Abstract

The effect of solution treatment temperature on the tensile properties of an AI-7 Si-0.3Mg (wt-%) alloy has been studied using tensile and hardness testing, microprobe composition analysis, and differential scanning calorimetry. With a sufficiently long solution treatment time, an increase in solution treatment temperature from 500 to 560°C significantly increases the silicon content in the matrix, but has little effect on the magnesium content. This results in a slight increase in the peak aged yield strength, but a more significant increase in the peak aged ultimate tensile stress and hardness. The alloy ductility is independent of solution treatment temperature, but is clearly influenced by the degree of eutectic silicon particle spheroidisation and coarsening. Using a higher solution treatment temperature can shorten the solution treatment time required to achieve a given tensile elongation value.