Effect of Aging Treatment Temperature on Microstructure and Properties of Al-9.3Si-0.41Mg-0.2Zr-0.01Sr-0.08Ti-0.2Ce Cast Aluminum Alloy

In this paper, the influence of three aging temperatures (165, 175, and 185 degrees C) under identical aging time (6 h) on the microstructure and properties of Al-9.3Si-0.41 Mg-0.2Zr-0.01Sr-0.08Ti-0.2Ce casting aluminum alloy was investigated. As the aging temperature raised from 165 to 185 degrees C, the alloy exhibited finer microstructure evolution, transitioning from primarily GP zones to beta '' phase, beta ' phase (Metastable phase), and ultimately beta (Mg2Si) phase (Stable phase). The strengthening effect due to dislocations initially increased and then diminished. Mechanical property tests indicated that with the elevation of aging temperature, the alloy's tensile strength and hardness demonstrate a trend of initially rising and then declining due to the effective strengthening effect of beta '' phase. The maximum tensile strength reached 288.78 MPa, the maximum yield strength was 259.38 MPa, and the maximum hardness was 118.89 HV. Additionally, alloy samples aged for 6 h at 175 degrees C displayed discontinuously distributed grain boundary precipitates, exhibiting good electrical conductivity and corrosion resistance.