Effects of Ce, Mn, Cr on the Microstructure and Properties of High-iron Eutectic Al-Si Piston Alloy

The paper discussed the effects of Ce, Mn, Cr on the microstructure and properties of high-iron eutectic Al-Si piston alloy using orthogonal design. It has been found that Mn and Cr improved the morphology of beta phase (Al9FeSi3), becoming the Fe phase that consists of Mn and Cr; Rare earths Ce has a strong effect on refinement of the eutectic silicon. At a high mass fraction of Ce, Ce enter Fe phase that contains Mn and Ce, which improves its morphology greatly and decreases the size of Fe phase, and is able to replace the position of Ni, becoming high-temperature Al-Ni-Cu-Ce phase. The best additions of Ce, Fe, Mn, Cr would be 0.8%, 1.0%, 0.4% and 0.1% respectively and the tensile strength under room temperature (25 degrees C) and high temperature(300 degrees C) would reach 270.3MPa and 136.7MPa respectively, which fully meet the requirements of the use of novel the piston high temperature load.