Quantitative analysis of the dependence of hardening on copper precipitate diameter and density in Fe–Cu alloys

In order to investigate the dependence of hardening on copper precipitate diameter and density, in situ TEM observations during tensile tests of dislocation gliding through copper precipitates in thermally aged Fe–Cu alloys were performed. The obstacle strength has been estimated from the critical bow-out angle, ϕc, of dislocations. The obstacle distance on the dislocation line measured from in situ TEM observations were compared with number density and diameter measured by 3DAP (three dimensional atom probe) and TEM observation. A comparison is made between hardening estimation based on the critical bowing angles and those obtained from conventional tensile tests.