Effects of solid solution temperature on the microstructure and properties of 6013 aluminum alloy

The components as well as the formation and heat treatment processes of the Al–Mg–Si–Cu aluminum alloy have been investigated in detail. However, only a few reports have considered the effects of solid solution treatment on the microstructure and properties of 6013 aluminum alloy during the aging process. In this study, the effects of solid solution temperature on the microstructure and properties of the 6013 aluminum alloy were studied via mechanical property testing, intergranular corrosion testing, electrochemical testing, and scanning and transmission electron microscopy. The results indicated that when the solid solution temperature of the alloy increased from 530 to 570 °C, the residual Mg2Si phase gradually decreased and the quantity of residual Al(FeMn)Si phase did not significantly change. As the solid solution temperature increased, the tensile strength, micro-hardness, and corrosion resistance of the alloy after T6 aging gradually increased, and the elongation and electrical conductivity, in turn, gradually decreased. Transmission electron microscopy depicted that the GP Zones and L phases of the alloy in the T6 state were observed. As the solid solution temperature increased, the quantity of the GP Zones and L phases increased, thereby increasing the material strength. The number of precipitates in the grain boundary gradually decreased, and the distribution distance gradually increased, which attenuated intergranular corrosion.