![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
The effects of strain rate change and strain reversal on flow stress and recrystallisation rate have been investigated in several steels in both the austenite and ferrite phases. It has been shown that when the strain rate is abruptly decreased, the flow stress clearly lags behind the behaviour of a mechanical equation of state. The static recrystallisation kinetics lags even more as the recrystallisation rate remains close to that at the high initial strain rate. However, because the effect of strain rate on the static recrystallisation kinetics is small, the average strain rate can be used to achieve fair accuracy in modelling. The history effects seem to be qualitatively independent of the steel chemical composition, and similar in ferrite and in austenite. Reversing the direction of deformation from tension to compression results in a retarded recrystallisation rate, up to 6–8 times at small reversed strains, for both austenite and ferrite. However, the coarsening of recrystallised grains at small reversed strain is much more pronounced in ferrite than in austenite.