COLD WORK-HARDENING IN STAGE-IV AND STAGE-V OF FCC METALS .2. MODEL FITS AND PHYSICAL RESULTS

The paper presents a common concept for work hardening of f.c.c. metals at temperatures below 0.5 T(m) up to very high strains. The concept considers statistical dislocation dynamics in terms of screw and edge dislocations and their specific interactions, and also allows for deformation-induced vacancies. By fitting the concept equations to experiment and using measured interaction parameters, very good agreement with strengthening data and dislocation densities of Cu and Al is achieved. The resulting fit parameters exhibit the expected order of magnitude and temperature dependence of dislocation storage and annihilation, for each dislocation type. The annihilation parameter of edge dislocations yields vacancy migration enthalpies of almost-equal-to 0.2 eV for Cu and Al indicating core migration of vacancies. From this the vacancy concentration is calculated for all strains and temperatures in question. Up to almost-equal-to 0.3 T(m), the saturation concentration of vacancies decreases, but reincreases beyond this temperature following the thermal vacancy concentration.