Solid-Solution Incipient Melting of Homogenized Al–Cu–Mg–Fe Alloy

Incipient melting of homogenized Al–4.5Cu–1.5 Mg–0.1Fe (wt%) alloy, which refers to the intermetallics basically eliminated after homogenization except Al7Cu2Fe phase, has been found under 590 °C. Abnormal phenomenon of the direct formation of a large number of fine dispersed particles and rapid dissolution of Cu- and Fe-rich phases has been observed during the 590 °C annealing process. The gradual gathering of the Cu and Mg solute in Al matrix as liquid phase since the temperature is much higher than its liquidus has been found to be the main reason for such solid-solution incipient melting. This work should provide some guidance for the homogenization process design of Al alloys.