HYDROGEN INTERACTION WITH SUBSTITUTIONAL SOLUTES AND SHORT-RANGE DECOMPOSITION IN FCC IRON-BASED SOLID SOLUTIONS

摘要

Hydrogen-metal atomic interactions and short-range atomic order in the fcc Fe- Ni-H solid solution have been studied using ab initio calculations of the electron structure, X-ray diffraction and TEM. It was obtained that the Fe-Fe and Ni-Ni interatomic bonds prevail over the Fe-Ni ones and the Fe-H interaction energies are higher than Ni-H ones. This result suggests a short-range decomposition of the Fe-Ni solid solution and inhomogeneous hydrogen distribution between the Fe- and Ni-rich areas. The theoretical calculations are supported by hydrogen-caused splitting of gamma reflections in the X-ray diffraction patterns and measurements of stacking fault energy in the hydrogen-charged Fe-50.8Ni alloy.