The effect of hydrogen on thermo-mechanical properties and in-use performance of metals and metal alloys is of critical importance, in particular in structural applications. In recent years, the relevance of H-metal interactions and their influence on expected performance have been broadened into functional metallic compounds and alloys as they are being used in energy, health and catalysis applications. In this work, we focused on NiAl compounds and shape memory alloys to assess the influence of H on thermal, physical, chemical, and mechanical properties using molecular dynamics (MD) and density functional theory (DFT) methods. The following alloys, Ni3Al, Al3Ni, NiAl, have been studied with H-content varied from 1% to 10% by MD at temperatures from 0 oK to 2100 oK for single crystals in B1, B2, L10, A4 structures and random and ordered L12 alloys. Furthermore, we studied specific bi-crystals with CSL grain boundaries: for B2 ? 5(210), ? 5(310), and ? 3(210); for L10 ? 5(210), ? 5(310), ? 3(210) to establish enthalpy-temperature concentration, volume-temperature concentration, volume-pressure-concentration relationships from which thermodynamic and mechanical response coefficients such as specific heats, thermal expansion, bulk modulus and isothermal compressibility and isothermal tensile and compression moduli and young moduli were determined by applying appropriate mechanical stresses.
