Effect of Ti and Ce Microalloy on Microstructure and Properties of Al-Si-Cu-Zr-Sr Cast Aluminum Alloy

The effect of Ti and Ce microalloying on the mechanical properties of Al-9Si-3.5Cu-0.2Zr-0.1Sr cast aluminum alloy was investigated, and it was hoped that the cast aluminum alloy with excellent comprehensive properties could be obtained. On the basis of Zr-Sr microalloyed cast aluminum alloy (Al-9Si-3.5Cu-0.2Zr-0.1Sr), the effects of 0.2Zr-0.1Sr-0.16Ti ternary microalloying and 0.2Zr-0.1Sr-0.16Ti-0.1Ce quaternary microalloying on the microstructure and properties of the alloy were investigated. The experimental results show that compared with Zr-Sr microalloying, Zr-Sr-Ti microalloying and Zr-Sr-Ti-Ce microalloying can effectively refine the microstructure, improve the modification effect of Si phase, and promote the improvement of Al2Cu phase, thus improving the properties. The higher the degree of microalloying, the hardness is gradually increasing, but the electrical conductivity is gradually decreasing. Zr-Sr-Ti microalloying can increase the tensile strength of the alloy to 400.07 MPa and the elongation to 9.5%. Zr-Sr-Ti-Ce microalloying do not continue to improve the properties of the alloy, and the tensile strength and elongation after fracture decrease to a certain extent due to the addition of Ce. Therefore, the best comprehensive properties can be obtained by Zr-Sr-Ti microalloying (Al-9Si-3.5Cu-0.2Zr-0.1Sr-0.16Ti).