Impact of Severe Plastic Deformation on the stability of MgH2

Abstract

Severe Plastic Deformation e.g. by using Equal Channel Angular Pressing enables develop rapidly large density of defects in magnesium batches. During the process no additive is used, no more needs to enhance the specific surface during SPD treatments.The mechanical characteristics of Mg and Mg alloys (AZ31, ZK60) were studied before and after the ECAP processing. It was observed that the process develops large texture and then installs anisotropic mechanical properties. As a typical result with hcp crystals, ECAP generated basal plane sliding allowing develop a high density dislocations. Another mode of deformation has consisted create a large density of twins a phenomenon occurring better with brittle samples. The analysis of the textures formed during the ECAP process has revealed that for Mg based alloys, the twin density had increased mostly in the {102} planes with respect to the 〈−101〉 shears.Hydrogen-activation traces were recorded on the different processed samples, before and after the ECAP treatment demonstrating that it has enabled favorable conditions of hydrogenation/dehydrogenation upon a development of twin boundaries.