Influence of Forging Temperature on Microstructure and Tensile Properties of High Alloyed Al-Zn-Mg-Cu Alloy

A highly alloyed Al-Zn-Mg-Cu alloy ingot was prepared by the direct-chill semi-continuous casting process with pure aluminum, pure zinc, pure magnesium, Al-50Cu master alloy and Al-4Zr master alloy as raw materials. The ingot was successively subjected to homogenization treatment double upsetting and double drawing forging at different forging temperatures （360, 380, and 400 ℃）, solution treatment at 473 ℃ for 2.5 h, and aging treatment at 121 ℃ for 24 h The influence of forging temperature on the microstructure and room-temperature tensile properties of the test alloy was studied. The results show that with the increase of forging temperature, the average grain size of the test alloy first decreased and then increased; the recrystallization degree first decreased and then increased; the proportion of deformation texture first increased and then decreased; the tensile strength and yield strength first increased and then decreased; the elongation after fracture showed little change. When the forging temperature was 380 ℃, due to the smallest grain size, lowest recrystallization degree and highest proportion of deformation texture, the test alloy exhibited the highest strength and the optimal room-temperature tensile properties.