The Medical Model of Impairment

Atomic mobility in Titanium grade 5 (Ti6Al4V)

“…To make calculation of interdiffusion in Ti-V binary HCP_A3 phase, the self-diffusion of V in a hypothetical V HCP_A3 structure was determined. To do it, the Leclair's [5] and Askil's [6] models, given by Equations 11 and 12, were used. The lattice constants were taken from ab initio calculations provided by Wang et al [35], and the melting temperature of V in HCP_A3 was calculated from SGTE 5.1 database [36] as 1413.5 K. After applying the data to Equation 11 and 12, the self-diffusion of V in HCP_A3 was calculated.…”

“…The same procedure, as in a case of hypothetical HCP_A3 V, was applied to calculation of mobility parameters in hypothetical Al BCC_A2 and HCP_A3 structures, i.e. the semiempirical models given by Leclair [5] and Askil [6] were used for calculation of selfdiffusion of Al and model given by Du et al [7] was used for calculation of interdiffusion. The crystal structure data for both atomic arrangements was taken from ab-initio calculation given by Wang et al [35].…”

“…It is possible to rewrite Eq. 4 in a form: (5) where 6is a parameter. The superscript  suggests connection between and frequency parameter [J mol -1 ].…”

“…In the case of the ternary Al -Ti -V system there are hypothetical BCC_A2 and HCP_A3 lattice for Al and Al, Ti, respectively. The self-diffusivity of these elements in the hypothetical crystal lattice is calculated based on the empirical relation given by Leclair [5]: (11) and by Askill [6]: (12) where K is a structure factor equal 15.5 for a HCP_A3 phase, and equal 13 for BCC_A2 structure, V is the valence and a is the lattice constant [nm] and T f is melting temperature [K]. The impurity diffusion coefficients in hypothetical Al BCC_A as well as Al HCP_A3 and V HCP_A3 were obtained from Du et al [7] approach given by Equation 13 and 14:…”