Role of shear stiffening in reducing hydrogenation in intermetallic compounds

The authors report on a pronounced increase in the elastic shear modulus of a wide class of binary intermetallics upon pseudobinary substitution. They further claim that the aforementioned increase in the rigidity of these compounds is the mechanism underlying the well documented, sharp decline of hydrogen absorption in these compounds. They suggest that a clamping effect occurs in the bulk due to the high shear modulus, preventing the formation of dislocations and thus inhibits the hydrogenation. Identifying this mechanism suggests that, in order to reach good hydrogen absorbers, effort should be invested in designing compounds where shear stiffening does not occur.