Effect of B addition on the microstructure and properties of Zn-3.5Al biodegradable zinc alloy.

• Boron affects the metabolism of sugar, protein and fat and has estrogenic effects. • This paper adopts the metal mold gravity casting to prepare Zn-4Al-xB alloy. • The η (Zn) and α (Al) + η (Zn) layered structure are refined. • The elongation of Zn-4Al-0.15B is 0.92%, about three times of without B addition. • The corrosion rate is 32.7 μm/year, 1/3 of the value of alloy without B addition. The effect of B addition on the microstructure, mechanical properties, and in vitro degradation behavior of Zn-3.5Al alloy was studied using Zn-3.5Al as the matrix alloy. The results indicate that the dendrites η (Zn) and eutectic structure α (Al) + η (Zn) layered structure are refined with B addition. As the amount of B element addition increases, the tensile strength and corrosion rate of zinc alloy decrease, while the elongation increases. When the amount of B element added is 0.15 wt%, the tensile strength of zinc alloy is 182 MPa, and the elongation is 0.92 %, which is about three times that of the zinc alloy without B addition. The corrosion rate is 32.7 μm/year, approximately one-third of the value of alloy without B addition. [ABSTRACT FROM AUTHOR]