Effect of compound inoculants Ti and Zr on as cast microstructure and mechanical properties of Al-Cu alloy

Control of as cast grain size is important for Al-Cu alloys and always achieved by inoculation. In this paper, the microstructure and mechanical properties of Al-Cu alloy were investigated by adding compound inoculants Ti and Zr. The results show that the refinement effect of Ti and Zr is compatible in the Al-Cu alloy. Al3Ti and Al3Zr were formed in Al-Cu alloy with additions of a little Ti and Zr, which respectively provided the heterogeneous nucleation sites for alpha-Al. Intermetallic aluminised dispersions Al-3(Ti, Zr) were formed with additions of large amounts of Ti and Zr in AlCu alloy, which accelerated the heterogeneous nucleation of alpha-Al and resulted in refining grains of the Al-Cu alloy, so the tensile strength and elongation of Al-Cu alloy were increased. With the synthetical addition of w(Zr) = 50.5% and w(Ti) 50.3% in the Al-Cu alloy, the tensile strength of Al-Cu alloy reached 174.11 MPa and elongation rate reached 6.20%.