Strain-induced interaction of hydrogen atoms with dissolved atoms in IVA group metals

Abstract

The energies of strain-induced (elastic) H–H, D–D, H(D)–O(N,C) and H-substitutional interactions are calculated for the h.c.p. IVA group metals α-Ti, α-Zr and α-Hf taking into account the discrete atomic structure of the host lattice. The elastic constants, lattice spacing of the host lattice, and concentration expansion coefficients of the solid solution lattice due to dissolved atoms are used as the input numerical parameters. The interaction oscillates and is of long-range nature. In all solid solutions, coordination shells exist where the solute atoms attract each other. This interaction is stronger in α-Ti than in α-Zr and α-Hf. The hydrogen atoms interact more strongly with each other than with other solute atoms. A comparative analysis of interaction energies in the h.c.p. IVA group metals with those in b.c.c. and f.c.c. solid solutions revealed the determining effect of the crystal lattice type on both the interaction energy value and its dependence on interatomic distances. In general, the strain-induced interactions in h.c.p. IVA group metals are of the same order as in b.c.c. solid solutions and are stronger than in f.c.c. solid solutions.