High-temperature compression deformation strengthening mechanism of Mg–Gd–Y–Zn–Zr alloy formed by cold metal transfer (CMT) arc additive forming

Abstract

The Mg–Gd–Y–Zn–Zr alloy structural parts were formed by CMT arc additive forming. The high-temperature compression deformation strengthening mechanism of the alloy at 623–723 K, 0.01–1s−1, and 50 % deformation was studied. Upon a decrease in the temperature or an increase in the strain rate, the effect of fine-grain strengthening was obvious, which led to the improvement of the mechanical properties of the alloy after deformation. The grain refinement was mainly attributed to the DDRX and CDRX processes during hot deformation. Because the compression specimen was loaded along the building direction, the twins after deformation were compression twins {10–11}, and the content increased with an increase in the strain rate or a decrease in the temperature. As the strain rate increased, the texture distribution on the {10-10} plane became more concentrated and the texture intensity decreased from 6.79 to 2.24. This was attributed to the fact that the alloy was mainly dominated by a non-basal slip during high-temperature deformation, which increased the sensitivity of the strain rate to the texture.