Modes of dislocation nucleation in lamellae

Mode A, nucleation of a monolithic straight screw-dislocation line from the edge of a lamella 

The Gibbs free-energy change AG, per unit length, for insertion of a fully formed screw-dislocation line from the edge to a critical distance r from the edge under an applied shear stress r (= ris), as depicted in Fig. 9.17(b), is (Argon et al. 2005) 

We note that if the ideal shear resistance of the (100) [001] plane system were given by a Frenkel sinusoid (Frenkel 1926) then the ideal shear strength of this system would be 

Introducing the thickness 1 of the lamellae gives the final activation free energy AG of this mode A as 

This form of the expression applies to cases of conventional FIDPE with lamella thicknesses 1 20 nm. 

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