Effects of Fe content on microstructure and mechanical properties of A206 alloy

The effects of Fe content on the microstructure (intermetallic compounds, available copper and strengthening precipitates) and mechanical properties of A206 alloy have been investigated. The network of CuAl₂ and needle-like (or platelet-like) Cu₂FeAl₇ compounds, which coexist in the α-Al inter-dendrites, characterize the typical solidification structures of A206 alloys. The volume fraction and number of Cu₂FeAl₇ needles, determined by image analysis, are proportional to the Fe content. The available copper and the supersaturated copper atoms in matrix in richer Fe alloys will decrease after the solution treatment. In DSC analysis, the smaller heat effect and the increase in peak temperature for precipitation θ′ phase suggest that the amount and kinetics of precipitation are lowered in higher Fe content alloys. The relation between the mechanical properties and microstructure has been examined quantitatively. The tensile strength and hardness are mainly dominated by the volume fraction of θ′ phase, and the elongation by the Cu₂FeAl₇ compound. All of these properties, especially the elongation, decrease when the Fe content increases because of reduced quantity of θ′ phase and increased amount of Cu₂FeAl₇ compounds. The tensile strength decreases linearly with increasing Fe content.