13th International Conference on Fracture June 16–21, 2013, Beijing, China -10- count on micro-level determined mobility, binding and kinetics rates characteristics, which complicates their implementation in engineering. Regarding suitability for HAF description of explicit models of trapping-affected diffusion with or without lattice-trap equilibrium, this is basically the matter of transportation distances and corresponding times relevant to HAF process, so that whenever they are short, account for lattice-trap exchange kinetics may be advisable. However, one ought to be aware that large concentration gradients that can be met, e.g., in the proximity of hydrogen entry surface at short diffusion times can invalidate the requisites of smallness of the ratios of partial concentrations and their gradients, which justify the reduction of general system of diffusion equations (9) to the special case (22) of McNabb-Foster. At any rate, recognising that trap populations may be affected by plastic deformation εp, NT = NT( εp), and that the most relevant field for HAF is the stress field, U ∝ σ, all considered equations describe the process of stress-strain assisted diffusion [1,4-6,16]. This way, present study gives an outlook of “microstructure informed” models of stress-strain affected hydrogen diffusion able to account for various physical variables relevant to HAF. Acknowledgements This undertaking was inspired by challenges of the EU’s 7FP Project “MultiHy” (http://multihy.eu). References [1] J. Toribio, V. Kharin, Corr. Rev., 19 (2001) 207–252. [2] J.P. Hirth, Met. Trans., A11 (1980) 861-890. [3] R.P. Gangloff, in: Comprehensive Structural Integrity. Vol. 6, Elsevier, 2003, pp. 31–101. [4] P. Sofronis, R. McMeeking, J. Mech. Phys. Solids 37 (1989) 317-350. [5] J. Toribio, V. Kharin, ASTM STP 1343 (1999) 440-458. [6] A. Krom, A. Bakker, Met. Trans., B31 (2000) 1475-1482. [7] A. McNabb, P. Foster, Trans. AIME 227 (1963) 618-627. [8] I. Bekman, in: Interaction of Hydrogen with Metals, Moscow, 1987, pp. 143-177. [9] J. Waisman, G. Sines, L. Robinson, Met. Trans. 4 (1983) 291-302. [10] J. Leblond, D. Dubois, Acta Met. 31 (1983) 1459-1469. [11] S. Bokshtein, et al, Thermodynamics and Kinetics of Diffusion in Solids, Oxonian Press, 1985. [12] V. Kharin, Sov. Materials Sci. 23 (1987) 348-357. [13] R. Kirchheim, Acta Met. 30 (1982) 1069-1078. [14] A. Pisarev, B. Chernikov, in: Interaction of Hydrogen with Metals, Moscow, 1987, pp. 233264. [15] Y. Fukai, The Metal-Hydrogen System, Springer, 2005. [16] J. Toribio, V. Kharin, Materials Sci. 42 (2006) 263-271. [17] R. Oriani, Acta Met. 18 (1970) 147-157. [18] R. Barrer, J. Membrane Sci. 18 (1984) 25-35. [19] J.M. Hill, Scr. Met. 13 (1979) 1027-1031. [20] A. Allnatt, A. Lidiard, Atomic Transport in Solids, Cambridge Univ. Press, 2003. [21] H. Wipf, Phys. Scripta T94 (2001) 43-51. [22] R. Fuentes-Samaniego, J. Hirth, Phys. Stat. Solidi 106 (1981) 359-371. [23] R. Barrer, Diffusion in and Through Solids, Cambridge Univ. Press, 1951.
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