Microstructural evolutions and mechanical properties of 6082 aluminum alloy part produced by a solution-forging integrated process

Abstract

The conventional forging process for 6082 aluminum alloy entails the following steps: preheating, hot forging, solution heat treatment (SHT), and artificial aging. In this study, 6082 aluminum alloy automobile parts were successfully manufactured under industrialized conditions using a novel forging process that integrated SHT and hot forging into one operation, resulting in the cost savings compared with the conventional forging process. Mechanical properties were determined using tensile tests, while microstructural evolutions were revealed using optical microscopy (OM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), high-resolution transmission electron microscopy (HRTEM), and finite element method (FEM) simulation. It is found that the abnormal grain growth (AGG) induced by post-forging SHT occurred in the surface layer of conventionally processed parts, resulting in a decrease in the strengthening effects of grain boundary and dislocation, as well as a decrease in tensile strength, yield strength, and elongation. However, benefiting from the SHT before forging and the immediate quenching after forging, the AGG triggered by secondary recrystallization was suppressed by using the novel forging process. Along with achieving mechanical properties comparable to those obtained through conventional forging in the interior, the novelly processed parts' surface layer exhibits relatively consistent properties due to their homogeneous grain structure. The results above demonstrate the efficacy of the novel solution-forging integrated process, which is well-suited for industrial production, application, and promotion.