Revision as of 01:11, 19 December 2007

Frank-Read source is a type of dislocation multiplication mechanism. Consider a segment whose ends are pinned(corresponding to nodes in a network, precipitates, or sites where the dislocation leaves the glide plane). Under a certain applied stress the segment bows out by glide. As bow-out proceeds, the radius of curvature of the line decreases and the line-tension forces tending to restore the line to a straight configuration increase. For stress less than a critical value, a metastable equilibrium configuration is attained, in which the line-tension force balances that caused by the applied stress. For the large bow-out case, following equilibrium condition holds:

Failed to parse (lexing error): b\mathbf{\sigma}=\frac{\mu b^2}{4\pi r(1-\nu)}\left \{ \left \[ [1-\frac{\nu}{2}(3-4cos^2 \beta)\right \] ln\frac{L}{\rho}-1+\frac{nu]{2}\right \}