Element segregation behavior of aluminum-copper alloy ZL205A

TG146.21; In aluminum-copper al oy, the segregation has a severe bad effect on the al oying degree, strength and corrosion resistance. A deeper understanding of element segregation behavior wil have a great significance on the prevention of segregation. In the study, the element segregation behavior of ZL205A aluminum-copper al oy was investigated by examining isothermal y solidified samples using scanning electron microscopy and energy dispersive spectroscopy. The calculated results of segregation coefficients show that Cu and Mn are negative segregation elements; while Ti, V and Zr are positive segregation elements. The sequence of element segregation degree from the greatest to the least in ZL205A al oy is Cu, Mn, V, Ti, Zr and Al. The density of residual liquid is expected to increase with a decrease in the quenching temperature ranging from 630 oC to 550 oC. The calculated results confirm that the quenching temperature has an insignificant effect on the liquid density;and the variation of density is mainly due to element segregation. Consequently, segregations of Al, Cu and Mn lead to an increase in density, but Ti, V and Zr present the opposite effect. The contribution of each element to the variation of the liquid density was analyzed. The sequence of contributions of al oying elements to the variation of total liquid density is Cu﹥Al﹥Mn﹥V﹥Ti﹥Zr.