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

The effects of Fe content on the microstructure (intermetallic compounds, a vailable copper and strengthening precipitates) and mechanical properties o f A206 alloy have been investigated. The network of CuAl2 and needle-like ( or platelet-like) Cu2FeAl7 compounds, which coexist in the cr-Al inter-dend rites, characterize the typical solidification structures of A206 alloys. T he volume fraction and number of Cu2FeAl7 needles, determined by image;anal ysis, are proportional to the Fe content. The available copper and the supe rsaturated copper atoms in matrix in richer Fe alloys will decrease after t he solution treatment. In DSC analysis, the smaller heat effect and the inc rease in peak temperature for precipitation partial derivative' phase sugge st that the amount and kinetics of precipitation are lowered in higher Fe c ontent alloys. The relation between the mechanical properties and microstru cture has been examined quantitatively. The tensile strength and hardness a re mainly dominated by the volume fraction of partial derivative' phase, an d the elongation by the Cu2FeAl7 compound. All of these properties, especia lly the elongation, decrease when the Fe content increases because of reduc ed quantity of partial derivative' phase and increased amount of Cu(2)Fel(7 ) compounds. The tensile strength decreases linearly with increasing Fe con tent.