Effects of Compound Addition of Zr and Sc on Cast Microstructure and Mechanical Properties of AlFeSi Alloys

Al FeSi alloys with different contents of Zr and Sc were prepared by a well resistance furnace. The effects of trace rare earth elements Zr and Sc on the mechanical properties and microstructure of as-cast Al FeSi alloys were investigated by universal testing machine, scanning electron microscope and X-ray diffractometer. The results show that the best tensile strength, hardness and grain size are 171.55 MPa, 75.58 HV and 45.78 μm, respectively, when Zr and Sc are added together and the mass fraction is 0.2wt%. The second phase Al₃(Sc, Zr) particles can be formed after adding trace elements of Sc and Zr,which acts as the heterogeneous nucleation core during the solidification process and promote the heterogeneous nucleation of Al FeSi alloy liquid, thus refining the Al FeSi alloy grains.