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Redistribution of Vacancy Concentration in Metal Specimens under Stress-induced Diffusion at a High Temperature  

Yoon, Seon-Jhin (DPAMSTECH Co., Ltd.)
Cho, Yong-Moo (Dept. of Aerospace & Mechanical Engineering, DONG SEOUL University)
Publication Information
Design & Manufacturing / v.12, no.1, 2018 , pp. 1-6 More about this Journal
Abstract
In this study, we calculated the redistribution of vacancy concentration in metal specimens induced by stress-induced diffusion at a high temperature. To deduce the governing equation, we associated the unit volume change equation of strains with a differential equation of vacancy concentration as a function of stress using the stress-strain relationship. In this governing equation, we considered stress as the only chemical potential parameter to stay in the scope of this study, which provided the vacancy concentration equation as of stress gradient in metals. The equation was then mathematically delineated to derive a analytical solution for a transient, one-dimensional diffusion case. With the help of Korhonen's approximation and the boundary conditions, we successfully deduced a general solution from the governing equation. To visualize the feasibility of our solutions, we applied the solution to two different stress-induced cases - a rod with fixed concentrated stresses at both ends and a rod with varying concentrated stresses at both ends. Although it is necessary to legitimatized the model in the future for improvement, our results showed that the model can be used to interpret the location of structural defects, the formation of vacancy, and furthermore the high temperature behavior of metals.
Keywords
Concentration; Creep; Diffusion; Stress; Vacancy;
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