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

Abstract

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).

Keywords

cast aluminum alloy / microalloying / mechanical properties / Al-Si-Cu