Influence of Cu on the mechanical properties and precipitation behavior of AlSi7Mg0.5 alloy during aging treatment

The influence of Cu on the mechanical properties of AlSi7Mg0.5 alloy after T6 heat treatment has been studied. The tensile strength and peak age hardness increase while the elongation decreases with increasing Cu content in the alloy. The investigation of the precipitation behavior of dispersoids during aging by transmission electron microscopy (TEM) and high resolution TEM shows that Cu addition increases the density of the β″ precipitates and induces the precipitation of precursors of Q phase at the peak aged condition. When the Cu content is high, θ′-Al2Cu phase also precipitates during artificial aging.