dislocation theory

On February 7, 1934, two consecutive papers by Sir Geoffrey Ingram Taylor were received and so the dislocation theory was born and the first attempt at describing work hardening was made. Before that date, it was known that there was a big gap between the ideal and the experimentally observed shear strength. While according to the calculations, the shear strength had to be of the order of one tenth (or with finer models one thirtieth) of the shear modulus, the measured shear strength was several orders of magnitude smaller. This large discrepancy brought about Geoffrey I.Taylor, Egon Orowan and Michael Polyani to independently postulate the existence of dislocations. Papers by Orowan and Polyani were published consecutively in one volume of Zeitschrift für Physik.