Effect of Heat and Mechanical Treatments on Mechanical Properties of Al-Zn-Mg-Cu Alloys

Abstract

In this research the effect of various heat treatments on tensile properties and hardness of Aluminum-Zinc-Magnesium-Copper alloy (7075 Aluminum alloy) was studied, with and without mechanical treatment by extrusion process. The 7075 alloy samples were submitted to two type of heat treatments, T6 heat treatment by artificial ageing samples in 120 ºC for 24 h and retrogression and re-ageing (RRA). Where in RRA treatment the first ageing done in 120 ºC for 24 h, then the retrogression done in 180 ºC for 30 min and re-ageing in 120 ºC for 24 h. We got the best results by apply the RRA treatment with extrusion process, where tensile strength was reached to 380 Mpa without extrusion machining process, while reached to 530 Mpa with extrusion process