Identification and analysis of a reverse dynamic strain ageing in welded joints of C-Mn steels in the secondary circuit welds of nuclear power plants

Abstract

In an original way, we exploit a restricted region within the dynamic strain ageing domain where a simultaneous increase in strength and uniform elongation has been shown, with increasing free solute concentrations. This unusual reverse dynamic strain ageing was shown to be a marker of the interaction between strain ageing and strain hardening. Analysis, based on a dual experimental and theoretical approach, shows that dynamic strain ageing reduces the ability of the material to exhibit dynamic recovery. This regime operates at very low solute concentrations and saturates above a critical solute concentration. All the results obtained support the dislocations/solutes interactions as the main mechanism.