Elastoplastic transition in the material with sharp yield point

A study was made of the processes involved in the nucleation and propagation of Chernov–Luders bands in low carbon steels. It is found that the deformation bands are nucleated in the deforming sample at stress levels that are significantly lower relative to the upper yield limit. A sharp yield point is found to occur on the deformation curve, with its ascending and descending branches corresponding to the band nucleus “ingrowth”. Following the sharp yield point, a mobile Chernov–Luders band proper is observed for the yield plateau. The rate of deformation band fronts has been determined for both the band “ingrowth” and the band propagation stage. The occurrence of mobile band front(s) is considered. Thus, the conventional assumption that the deformation front is a boundary separating deformed and non-deformed material regions represents facts only approximately.