Effects of small addition of Sc on microstructure and mechanical properties of X2A66 alloy

Abstract

The effects of Sc addition on the microstructure evolution and mechanical properties of X2A66 alloy were studied by the experimental methods of mechanical property test and microstructure characterization. The results indicate that adding 0.18% Sc element in the X2A66 alloy can effectively refine the grain size, and form the primary phase of AlScZr or AlCuScZr with larger size, and also increases the over firing temperature of the as-cast alloy. Compared with Al3Zr particles, Al3(Sc, Zr) composite particles have better effect on restraining recrystallization, and make the alloy have smaller grain size during the subsequent deformation and heat treatment. However, AlCuSc and AlCuScFe phases can not be completely dissolved in the subsequent heat treatment process, which damages the mechanical properties of the solid solution alloy.