Severe Plastic Deformation by Fast Forging to Easy Produce Hydride from Bulk Mg-Based Alloys

抄録

The study of metal forging over long period of time has made it possible to establish the major basic principles up to the most recent, those of Severe Plastic Deformation (SPD). Thus the fundamental characteristics resulting from the stresses and deformations applied have led to the definition and modelling of microstructural variations in grain size and shape, density of dislocations, slip bands and twins, all factors to be considered during the transformation of the micro/nanostructure by SPD. For this purpose, SPD techniques such as ECAP, HPT, ARB have produced invaluable results namely in views of solid state hydrogen storage. So the present report focuses on magnesium-based materials with the aim of generating a deformed structure that will react quickly to allow massive and reversible hydrogen storage. However, all here above mentioned methods are rather difficult to scale up to mass production because they are either too time-consuming or too energy and labor intensive. Furthermore, it is revealed that at extreme, fast forging (FF) can introduce high densities of vacancies, voids and finally cracks in addition to grain refinement down to the ultrafine and nano-scale sizes. This leads in the FF worked material exhibiting excellent hydrogen reactivity as shown on a few examples.

Mg-based ample before (left) and after (right) forging.