Microstructure and mechanical properties of high damping Zn-Al eutectoid alloy reinforced by in-situ formed Al2O3 and Al3Zr particles

Zn-Al eutectoid alloy (ZA22) has ultra-high damping property, but its mechanical properties are still relatively low. In order to simultaneously improve the tensile strength and plasticity, a novel Al matrix composite inoculant containing in-situ formed Al2O3 and Al3Zr particles was designed and used to reinforce the ZA22 alloy. The microstructure of the ZA22 alloy was significantly refined. Fine Al2O3 particles were uniformly distributed in the alpha phase and the lamellar eutectoid structure, whereas Al3Zr particles were distributed in the alpha phase and at the alpha/eta interface. Property tests showed that the tensile mechanical properties of the reinforced ZA22 alloys were significantly improved. The maximum tensile strength and elongation reached 355 MPa and 7.62%, which were 1.50 and 1.89 times those of the original ZA22 alloy, respectively. The increase in mechanical properties is attributed to the multiple strengthening and toughening factors constructed in the refined microstructure.