Influence of high concentrations of solute atoms on the critical flow stress of binary alloys. II. Application to silver-, gold-, and copper-based alloys

Abstract

A previously developed theory of the critical flow stress due to high concentrations of solute atoms is further specified by the calculation of the interaction between solute atoms and dislocations due to a size and modulus difference between solute and matrix atoms. It turns out that the first‐order interaction due to the size difference cancels identically. Therefore, only second‐order effects are responsible for the critical flow stress due to high concentrations of solute atoms. This is demonstrated by the agreement between the calculated stress and the available experimental data on Ag‐, Au‐, and Cu‐based binary alloys. The length of the dislocation segment that moves as a whole was determined from these data to be about L=3×10−4 cm for all alloys, a value that is in agreement with the assumption that the length of the dislocation segment should be comparable to the distance between pinning points of a Frank‐Read source. This long dislocation segment does not allow for thermal activation and therefore is the basis for the temperature independence of the stress component, due to high concentrations of solute atoms.