Investigating the Effect of Aging Temperature, Magnesium, and Silicon Content on the Hardness of A6063 Alloy

This research investigated the magnesium (Mg), silicon (Si) content, and aging temperature's effect on the microstructure and hardness of Al-Mg-Si alloys using Response Surface Methodology (RSM). The study varied Mg content between 0.4% and 1%, Si content from 0.4% to 0.8%, and aging temperatures between 170 °C to 210 °C. The findings revealed that increasing the Mg content from 0.85% to 1% and optimizing aging temperatures between 180 °C and 195 °C significantly improved hardness, primarily due to the enhanced formation of magnesium silicide precipitates (Mg2Si). In contrast, lower Mg levels of 0.4%, Si content below 0.42%, or aging temperatures lower than 170 °C or higher than 200 °C resulted in reduced hardness. This reduction in hardness is linked to the limited precipitation of Mg2Si, which diminishes the obstacles to dislocation movement.