DOUBLE STRENGTHENING OF COPPER BY DISSOLVED GOLD--ATOMS AND BY INCOHERENT SiO_2-PARTICLES: HOW DO THE TWO STRENGTHENING CONTRIBUTIONS SUPERIMPOSE?

摘要

copper single crystals have been simultaneously strengthened by solved gold-atoms and by incoherent SiO_2-particles. The critical resolved shear stress (CRSS) T_s of a binary coppergold solid solution and the CRSS T_t of the same solid solution additionally strengthened by SiO_2-particles have been measured in the temperature range 90-283 K. From the experimentally established temperature dependences of T_s and T-1 and from the theoretically known one of T_P (= CRSS if the SiO_2-particles are the only strengtheners present), the function T_t (T_s,T_p) has been derived: T_t = (T~k_s + T~k_p)~l/k, with k≈l.8. This result is at variance with a linear relationship suggested earlier by Ebeling and Ashby [Phil. Mag. l3 (l966) 805]. The bearings of the present findings on the evaluation of experimental data on dispersion strengthening are evident.