Effect of trace yttrium on the microstructure, mechanical property and corrosion behavior of homogenized Mg–2Zn–0.1Mn–0.3Ca–xY biological magnesium alloy

The effects of trace yttrium (Y) element on the microstructure, mechanical properties, and corrosion resistance of Mg–2Zn–0.1Mn–0.3Ca–xY (x = 0, 0.1, 0.2, 0.3) biological magnesium alloys are investigated. Results show that grain size decreases from 310 to 144 μm when Y content increases from 0wt% to 0.3wt%. At the same time, volume fraction of the second phase increases from 0.4% to 6.0%, yield strength of the alloy continues to increase, and ultimate tensile strength and elongation decrease initially and then increase. When the Y content increases to 0.3wt%, Mg₃Zn₆Y phase begins to precipitate in the alloy; thus, the alloy exhibits the most excellent mechanical property. At this time, its ultimate tensile strength, yield strength, and elongation are 119 MPa, 69 MPa, and 9.1%, respectively. In addition, when the Y content is 0.3wt%, the alloy shows the best corrosion resistance in the simulated body fluid (SBF). This investigation has revealed that the improvement of mechanical properties and corrosion resistance is mainly attributed to the grain refinement and the precipitated Mg₃Zn₆Y phase.