A GRID METHOD QUANTIFYING DEFORMED MG-ALLOYS BY EQUAL-CHANNEL ANGULAR PRESSING

Received: 7 May 2015 Accepted: 17 June 2015 Published: 30 September 2015 Among the optimum solutions for hydrogen storage in terms of effectiveness and safety are metal hydrides. Magnesium and its alloys can reversibly absorb hydrogen in large amounts, so fulfilling the DOE's requirements and making those materials attractive for applications. At first, determining a fast hydrogen saturation of Mg-based alloys was consisted in grinding the materials up to micrometric grain size. Increasing markedly the specific surface of the treated powders by plastic deformation processing leads to delivering very reactive samples. As well, huge improvement of H-sorption characteristics of bulk Mgalloys was shown to be efficient under Equal Channel Angular Pressing (ECAP) treatments. During such a Severe Deformation Process, achievement of a fine grained microstructure in bulk samples is accompanied by the formation of defects and overall texture. The main achievements expected from the application of ECAP treatments to Mgrich alloys are: – formation of ultra-fine microstructures with high angle boundaries, which especially drastically changes the mechanical characteristics of the alloy, – volume homogenization of the microstructure for the best final stability of the hydrogenation properties of the refined material. Since in most cases a two or even more ECAP passes should be applied to deliver the highly reacting materials, the operating temperature must be adjusted in terms of ductile to fragile characteristics in order to avoid irreversible cracking of the bulk sample. After the application of the ECAP process, the resulting deformation was characterized using different methods such as conventional structural analysis and mechanical engineering followed by numerical simulations. The present article reports on the deformation process of Mg-based by using a grid evaluation method.