Differentiation on crystallographic orientation dependence of hydrogen diffusion in ?-Fe and ?-Fe: DFT calculation combined with SKPFM analysis

The crystallographic orientation dependence of hydrogen diffusion in alpha-Fe and gamma-Fe is examined using first -principle calculations and the scanning Kelvin probe force microscopy (SKPFM) technique. First-principle re-sults show that the hydrogen diffuses more slowly on (1 1 1) plane than on (001) and (101) planes in gamma-Fe, whereas hydrogen diffuses faster on (1 1 1) plane than on (001) and (101) planes in alpha-Fe due to the differences in diffusion barrier energy and charge uniformity. The SKPFM tests show hydrogen diffuses faster in (001) and (101) grains than in (111) grain in 304 austenitic stainless steel (gamma-SS), which has similar trends with calculation.

Automated summary

The crystallographic orientation dependence of hydrogen diffusion in alpha-Fe and gamma-Fe was studied using first-principle calculations and scanning Kelvin probe force microscopy (SKPFM) technique. The results revealed that hydrogen diffuses more slowly on (1 1 1) plane than on (001) and (101) planes in gamma-Fe, while it diffuses faster on (1 1 1) plane than on (001) and (101) planes in alpha-Fe due to the differences in diffusion barrier energy and charge uniformity. The SKPFM tests showed similar trends with the calculations, indicating faster hydrogen diffusion in (001) and (101) grains than in (111) grain in 304 austenitic stainless steel (gamma-SS).