Kinetics of Aging and Changes in the Mechanical Properties of Mg – Y – Nd – Gd – Zn – Zr Cast Magnesium Alloy During Overburning

Abstract

The microstructure and mechanical properties of a Mg – 3.5Gd –2.4Nd – 0.8Y – 1.0Zn – 0.7Zr (wt.%) alloy subjected to overburning during quenching and further aging at temperatures of 200, 250, and 300°C with an exposure duration of 1 – 100 h were studied. Tensile tests were carried out, and the microhardness of the alloy was determined. The Mg₃(Zn, REE) phase particles were shown to distribute along the grain boundaries after overburning, resulting in a significant softening of the material and a decrease in its mechanical properties. At the same time, the alloy subjected to aging at a temperature of 300°C showed stable strength properties regardless of the exposure duration. The exception is its relative elongation, which tended to increase with an increase in the exposure duration. Following aging at 200 and 250°C, the alloy exhibited the highest strength properties; however, the relative elongation values were close to zero.