Variation of stresses ahead of the internal cracks in ReNi(sub 5) powders during hydrogen charging and discharging cycles

摘要

In this study, the evolution of the stress-states ahead of the penny shaped internal cracks in both spherical and disk shaped ReNi(sub 5) particles where Re denotes the rare earths La, Ce, and Misch-metals during hydrogen charging and discharging cycles were investigated using coupled diffusion/deformation FEM analyses. The results indicate that large tensile stresses, on the order of 20--30% of the modulus of elasticity, develop in the particles. The disk shaped particles, in addition to having faster charging/discharging cycles, may offer better resistance to fracture than the spherical particles.