Influence of Cu and minor elements on solution treatment of Al–Si–Cu–Mg cast alloys

Abstract This paper has studied the influence of Cu content and microelements on solution treatment of Al–Si–Cu–Mg cast alloys by a series of differential scanning calorimetry (DSC) analyses. With the increase of Cu content, the melting point of α (Al)+Si decreases and polynary eutectic phases with melting point of 507 °C form. Sodium modification has little influence on the melting point of polynary eutectic phases, but it is increased by about 5 °C in Sr modified or Be-containing alloys. Incipient melting and the determination of two-step solution treatment (conventional solution treatment followed by a high-temperature solution treatment) parameters have been analyzed in unmodified and Sr modified Al11Si4Cu0.3Mg alloy. Factors influencing segregation should be considered in determining solution treatment parameters and this has been discussed.