STACKING-FAULT ENERGY MISMATCH STRENGTHENING REVISITED

The glide of a dissociated dislocation across a shearable coherent fee particle embedded in a fee matrix has been simulated on a computer. T he particle and matrix have different stacking-fault energies. The fle xibility of both partial dislocations has been fully allowed for. An A l-rich AI-Ag alloy served as a model system. Thus numerical values for the maximum interaction force F-0sim(rho) between the dislocation and the particle have been obtained; rho is the radius of its intersectio n with the glide plane. F-0sim(rho) is compared with the former analyt ical function F-0str(rho), which had been derived on the basis of the 'straight-line approximation'. F-0str(rho) turns out to be smaller tha n F-0str(rho). After a suitable adjustment; F-0str(rho) can be used to represent the numerical data F-0sim(rho). Inserting F-0str(rho) into Friedel's relation for the critical resolved shear stress yields an an alytical description of stacking-fault energy mismatch strengthening.