Atomistic simulations of hydrogen effects on lattice defects in alpha iron

Abstract

Solute hydrogen atoms degrade the strength of materials. This phenomenon, termed as hydrogen embrittlement (HE), has been a matter of concern for various industrial applications for more than a century. In recent years, HE has to be addressed because of the need for more efficient storage and transport of hydrogen. In this chapter, we present an overview of the current state of knowledge of the interaction between hydrogen and lattice defects. In Sect. 2, the hydrogen trap energy of various trap sites in alpha iron is reviewed and summarized. In Sect. 3, first, the hydrogen concentration around the defects is outlined based on the evaluation of the occupancy at each trap site. Subsequently, the effect of hydrogen on the stability and the kinetics of the lattice defects that trap hydrogen atoms are reviewed. In Sect. 4, mesoscopic calculations of the complex interactions among hydrogen-affected lattice defects are reviewed. Finally, the current state of knowledge of hydrogen effects on lattice defects and future directions are discussed. Alpha iron is considered because it is a basic steel component, and steel is a potential material for hydrogen storage and transport systems from engineering and economic viewpoints.