Effect of aging treatment on microstructure, mechanical and corrosion properties of 7055 aluminum alloy prepared using powder by-product

摘要

To effectively improve the mechanical properties of 7055 aluminum alloy prepared by powder by-products, aging treatment was carried out on the as-sintered 7055 alloy. The effects of different aging treatment parameters on the microstructure, mechanical and corrosion properties of the as-sintered 7055 alloy were investigated. The results show that the microstructure of as-sintered alloy is still a typical equiaxed crystal structure after aging treatment, however, the number of precipitated phases in matrix was significantly reduced and in uniformly fine needle-like distribution. The metastable η' phase is mainly precipitated. Moreover, the strength of the aging-treated sample is nearly doubled in comparison to that of the as-sintered alloy, and the sequence of the strength of three aging-treated sample is: RRA ＞ DA ＞ T6. The improvement of mechanical properties of the aging-treated sample is mainly attributed to the precipitation strengthening. Furthermore, the corrosion resistance of three aging-treated sample follows: DA ＞ RRA ＞ T6, and the continuous grains boundary precipitations and Fe-containing precipitates increase the corrosion susceptibility.