Synergistic Effects of B4C and Sn on the Coupled Growth Pattern and Mechanical Properties of Mg–Y–Zn–Mn Alloy Containing LPSO and W Phases

Abstract

The effect of boron carbide (B4C) particles and Sn on the microstructure and mechanical properties of Mg94Y2.5Zn2.5Mn1 alloy is mainly studied in this work. The results show that separated addition of B4C and Sn could not achieve very good results. The separated addition of Sn significantly promotes the formation of LPSO phase, but it cannot change the growth pattern of LPSO phase and W phase. Adding B4C changes the growth pattern of LPSO phase, but cannot effectively promote the formation of LPSO phase. The addition of B4C and Sn in combination achieves the growth pattern transformation of α‐Mg from irregular dendrite to equiaxed dendrite and refines the grain size, which makes LPSO phase and W phase no longer grow by coupled growth. When 0.02 wt% B4C and 0.35 wt% Sn is added, the Mg94Y2.5Zn2.5Mn1 alloy's growth pattern is changed and grains are refined, and thus exhibit superior mechanical properties. (Ultimate tensile strength of 255 MPa and elongation of 8.8%).