X-ray diffraction study on the microstructure of a Mg-Zn-Y alloy consolidated by high-pressure torsion

Abstract

Mg95Zn4.3Y0.7 (at.%) alloy powder produced by an inert gas-atomizer was consolidated by high-pressure torsion (HPT) at room temperature and 373 K. The phase composition and the microstructure were investigated by X-ray diffraction and the microstructural parameters were correlated to the yield strength. HPT-processing yielded an ultrafine-grained microstructure with high dislocation density, leading to a large yield strength of the samples. Both the gas-atomized powder and the consolidated samples contained an icosahedral Mg3YZn6 phase (I-phase) besides the main phase of alpha-Mg. It turned out that the I-phase dispersoids strengthen the consolidated material indirectly by increasing the dislocation density due to their pinning effect. (C) 2012 Elsevier B.V. All rights reserved.