The impact of F.R.N. Nabarro on the LEDS theory of workhardening

F.R.N. Nabarro has had a profound impact on the development of workhardening theory. Albeit, on account of his opposition to the LEDS/LES theory, that may be recognized as an emerging new paradigm, this has not always been positive. The LEDS/LES paradigm is ultimately based on Taylor’s 1934 workhardening theory. According to it, all plastic deformation of all solids under virtually any conditions, whether or not dislocations play a role in it, produces structures that closely approach minimum free energy, subject to Newton’s third law, i.e. force equilibrium. In due course, the LES/LEDS theory is expected to replace the previous SODS (“self-organizing dislocation structures” approach) that was supported by Nabarro. Namely, in contrast to the SODS approach, the LEDS/LES theory has long since quantitatively accounted for the bulk of all important aspects of crystalline plasticity and their correlated dislocation structures. It is argued that the protracted resistance against paradigm change, as also by Nabarro, is in line with Kuhn’s pertinent discussion in “The Structure of Scientific Revolutions”.