Investigation of quench sensitivity of high strength Al–Zn–Mg–Cu alloys by time–temperature-properties diagrams

Abstract

The quench sensitivity of some typical high strength Al–Zn–Mg–Cu alloys, including 7075, 7175, 7050, 7010, 7055, 7085 and 1933, was investigated by time–temperature-properties (TTP) diagrams which were from the present paper and literature. The drop in the mechanical properties due to decreased quenching rate was predicted by quench factor analysis method. The nose temperature of TTP diagrams was the highest for 7055 alloy and the lowest for 7085 alloy. The critical time at the nose temperature was the shortest for 7055 alloy and the longest for 1933 alloy. Decreased quenching rate to 10 k/s led to drop in the properties less than 2% for 7085 and 1933 alloys, but more than 20% for 7075, 7175 and 7055 alloy. Thus, 7075, 7175 and 7055 alloys were the most quench sensitive alloys, while 7085 and 1933 alloys were the least quench sensitive ones. The differences in the quench sensitivity of these alloys were explained mainly based on its chemical compositions.