Hydrogen-Induced Hardening in Palladium

Abstract:

In the present work, positron annihilation spectroscopy was employed for investigation of hydrogen-induced defects in Pd. Well annealed Pd samples were electrochemically charged with hydrogen and development of defects during hydrogen loading was investigated. At low concentrations (α-phase, x_H < 0.017 H/Pd) hydrogen loading introduced vacancies. When the hydrogen concentration exceeds 0.017 H/Pd, particles of hydrogen rich α’-phase are formed. This generates dislocations in the sample in order to accommodate the volume mismatch between the α and the α’-phase. Moreover, additional vacancies are introduced into the sample by crossing dislocations. Vickers hardness testing revealed that absorbed hydrogen causes hardening of the sample. In the α-phase region the hardness increases due to solid solution hardening caused by dissolved hydrogen. At higher hydrogen concentrations when dislocations were created hardness increases due to strain hardening caused by dislocations.

• Periodical: Defect and Diffusion Forum (Volume 365)
• Pages: 297-304
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.365.297
• Online since: July 2015
• Authors: Jakub Čížek, Oksana Melikhova, Ivan Procházka
• Keywords: Dislocations, Hardness, Hydrogen, Palladium, Positron Annihilation

References

[1] T.B. Flanagan, W.A. Oates, Annu. Rev. Mater. Sci. Vol. 21 (1991), p.269.

[2] P. Kumar, L. Malhotra, Mater. Chem. Phys. Vol. 88 (2004), p.106.

[3] H. -B. Zhao, K. Pflanz, J. -H. Gu, A. -W. Li, N. Stroh, H. Brunner, G. -X. Xiong, J. Memb. Sci. Vol. 142, (1989), p.147.

[4] A. Cabot, J. Arbiol, A. Cornet, J. Morante, F. Chen, M. Liu, Thin Solid Films Vol. 436 (2003), p.64.

DOI: 10.1016/s0040-6090(03)00510-8

[5] T. B. Massalski (Ed. ): Binary Alloy Phase Diagrams, ASM, Metals Park, OH (1993).

[6] A. Pundt, R. Kirchheim, Annu. Rev. Mater. Res. Vol. 36 (2006), p.555.

[7] R. Kirchheim, Prog. Mater. Sci. Vol. 32 (1988), p.261.

[8] R. Kirchheim, Acta Metall. Vol. 29 (1981), p.835.

[9] T. Mütschele, R. Kirchheim, Scripta Metall. Vol. 21 (1987), p.135.

[10] T. Mütschele, R. Kirchheim, Scripta Metall. Vol. 21 (1987), p.1101.

[11] F. Besenbacher, J.K. Norskow, M.J. Puska, S. Holloway, Nucl. Instrum. Methods Phys. Res. B Vol. 7-8 (1985), p.55.

[12] S.M. Myers, P.M. Richards, W.R. Wampler, F. Besenbacher, J. Nucl. Mater. Vol. 165 (1989), p.9.

[13] Y. Fukai, N. Ōkuma, Phys. Rev. Lett. Vol. 73 (1997), p.1640.

[14] R. Kirchheim, Acta Mater. Vol. 55 (2007), p.5129.

[15] R. Kirchheim, Int. J. Mater. Res. Vol. 100 (2009), p.483.

[16] P. Hautojärvi, in: Positrons in Solids, edited by. P. Hautojärvi, Springer-Verlag, Berlin (1979), p.1.

[17] J. Čížek, I. Procházka, F. Bečvář, R. Kužel, M. Cieslar, G. Brauer, W. Anwand, R. Kirchheim, A. Pundt, Phys. Rev. B Vol. 69 (2004), p.224106.

DOI: 10.1103/physrevb.69.224106

[18] F. Bečvář, J. Čížek, I. Procházka, J. Janotová, Nucl. Instrum. Methods A Vol. 539 (2005), p.372.

[19] I. Procházka, I. Novotný, F. Bečvář, Mater. Sci. Forum Vol. 255-257 (1997), p.772.

[20] J. M. Campillo Robles, E. Ogando, F. Plazaola, J. Phys.: Condens. Matter Vol. 19 (2007), p.176222.

[21] O. Melikhova, J. Čížek, I. Procházka, Acta Physica Polonica A Vol. 125 (2014), p.752.

[22] E. Ho, H.A. Goldberg, G.C. Weatherly, F.D. Manchester, Acta Metall. Vol. 27 (1979), p.841.

[23] R. West, in: Positrons in Solids, edited by P. Hautojärvi, Springer-Verlag, Berlin (1979), p.89.

[24] P. Hautojärvi, C. Corbel, in: Proceedings of the International School of Physics Enrico Fermi, Course CXXV, edited by A. Dupasquier, A.P. Mills, IOS Press, Varena (1995), p.491.

[25] H. J. Wollenberger, in: Physical Metallurgy, edited by R. W. Cahn and P. Haasen, North-Holland, Amsterdam (1983), Vol. 2, p.1146.

[26] M. Doyama, J.S. Koehler, Acta Metall. Vol. 24 (1976), p.871.