Effect of Heat Treatment on Microstructure and Mechanical Properties of Spray Deposited Al-Zn-Mg-Cu Aluminum Alloy

The effects of single solid solution treatment and two-stage solid solution treatment on the micro-structure and mechanical properties of spray deposited Al-Zn-Mg-Cu aluminum alloy were investigated. The micro-structure and precipitation were observed by optical microscopy, SEM and TEM. It is shown that the microstructure and mechanical properties by the two-stage solid solution treatment is better than those by the single solution treatment. The two-stage solution treatment has the advantages of low and high temperature single solution. After the two-stage solid solution, recrystallization grains did not grow up and most of precipitation were dissolved. The tensile strength and the yield strength of the alloy can reach 806 and 797 MPa respectively with a elongation of 7.5% after the two-stage solid solution and the T6 aging treatment.