Orowan bypass
= Orowan bypass
{c}
{title2=$\Delta\tau\simeq2T_\ell/(b\ell)$}
A <dislocation> unable to shear an obstacle can bow around it and leave a loop. Balancing the Peach-Koehler force against the tension of a curved <dislocation> gives the critical scale $\Delta\tau\simeq2T_\ell/(b\ell)$, where $\ell$ is the free obstacle span on the slip plane. Centre pitch and free span are not interchangeable when particle size is appreciable.