PSI - Issue 68

D.M. Tshwane et al. / Procedia Structural Integrity 68 (2025) 39–46 D.M. Tshwane et al. / Structural Integrity Procedia 00 (2025) 000–000

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Table 1. Calculated analysis of Mulliken charges and bond population for H adsorbed on Ti 2 AlV (110) surface. Structure Atoms Mulliken Charge (e - ) before Mulliken Charge (e - ) after Population Ti 0.08 0.11 0.44 H-Ti 2 AlV Al -0.39 -0.52 0.84 V 0.41 0.42 0.41 H -0.32

4. Conclusion In summary, the investigation of hydrogen adsorption on Ti 2 AlV (110) surface was succeeded using first-principle density functional theory. The current results showed that all the adsorption energies were negative, indicating an exothermic process and spontaneous events. More significantly, all the adsorption sites showed the influence of vdW forces and dispersion correction, with all adsorption energies being strong for !) "* # +,) > !) "* # + . The adsorption sites were shown to affect the calculated adsorption energies, with the Ti-V bridge site having the highest adsorption energy, suggesting that HE will mainly form and be stable at Ti-V bridge sites. Moreover, it was found that the Al element, or Al-rich is more resistant to H adsorption with lower adsorption energy strength ( !) "* # +,) = -4,042 eV) than the Ti site ( !) "* # +,) = -4,540 eV and V site !) "* # +,) = -4,612 eV). The charge density distribution plots showed that electrons build-up on the H atom and deplete on the surface atoms. Lastly, the Ti 2 AlV surface work function was seen to increase with H adsorption. According to the current findings, there is a higher chance of HE formation at the Ti-V site on the surface of Ti 2 AlV. Acknowledgements Department of Science and Innovation (DSI), National Research Foundation (NRF-Thuthuka) and the Council for Scientific and Industrial Research (CSIR) are acknowledged for funding this work. Finally, the Centre for High Performance Computing (CHPC) for computing resources. References Álvarez-Falcón, L., Viñes, F., Notario-Estévez, A., Illas, F., 2016. On the hydrogen adsorption and dissociation on Cu surfaces and nanorows. Surface Science 646, 221-9. Banerjee, D., Williams, J.C., 2013. Perspectives on titanium science and technology. Acta Materialia 61, 844-879. Chang, Y, Breen, A.J., Tarzimoghadam, Z., Kürnsteiner, P., Gardner, H., Ackerman, A., Radecka, A., Bagot, P.A.J., Lu, W., Li, T., Jägle, E.A., Herbig, M., Stephenson, L.T., Moody, M.P., et. al., 2018. Characterizing solute hydrogen and hydrides in pure and alloyed titanium at the atomic scale. Acta Materialia 150, 273-280. Deconinck, L., Bernardo Quejido, E., Villa Vidaller, M.T., Jägle, E.A., Verbeken, K., Depover T., 2023. The mechanism behind the effect of building orientation and surface roughness on hydrogen embrittlement of laser powder bed fused Ti-6Al-4V. Additive Manufacturing 72, 103613-14. Grimme, S., Ehrlich, S., Goerigk, L., 2011. Effect of the damping function in dispersion corrected density functional theory. Journal of Computational Chemistry 32, 1456-1465. Gutelmacher, E.T., Eliezer, D., 2004. Hydrogen-Assisted Degradation of Titanium Based Alloys. Materials Transactions 45, 1594-1600. Gutelmacher, E.T., Eliezer, D., 2005. The hydrogen embrittlement of titanium-based alloys. JOM: The Journal of The Minerals, Metals & Materials Society 57, 46-49. Hu, Q.M., Xu, D.S., Yang, R., Li, D., Wu, W.T., 2002. First-principles investigation of solute-hydrogen interaction in a α-Ti solid solution. Physical Review B 66, 064201. Kresse, G., 2000. Dissociation and sticking of H 2 on the Ni(111), (100), and (110) substrate. Physical Review B 62, 8295-305. Monkhorst, H.J., Pack, J.D., 1976. Special points for Brillouin-zone integrations. Physical Review B 13, 5188-5192. Olsson, P.A.T., Mrovec, M., Kroon M., 2016. First principles characterisation of brittle transgranular fracture of titanium hydrides. Acta Materialia 118, 362-373. Perdew, J.P., Burke, K., Ernzerhof, M., 1996. Generalized Gradient Approximation Made Simple. Physical Review Letters 77, 3865-3868. Segall, M.D., Philip, J.D.L., Probert, M.J., Pickard, C.J., Hasnip, P.J., Clark, S.J., Payne, M.C., 2002. First-principles simulation:ideas, illustrations and the CASTEP code. Journal of Physics: Condensed Matter 14, 2717-2744. Tshwane, D.M., Modiba, R., 2022. Structural stability of Cubic Ti 2 AlV and Tetragonal TiAl 2 V using first principle calculations. Proceedings SAIP 2022, 68-72 Tshwane, D.M., Modiba, R., 2022. Surface properties of Ti 2 AlV (100) and (110) surfaces using first-principle calculations. MATEC Web of Conferences 370, 09005-8.