Stress-strain diagrams of metals under large uniform compressive strains

Abstract

A new method was worked out for obtaining compressive stress-strain diagrams for large uniform plastic strains. For the first time correct compressive stress-strain diagrams of copper M2, steels St. 3, 45, 12KhN3A, U8A, and of the high-strength cast iron VCh-50 were obtained. In correct experiments at uniform state of stress the previously suggested postulate of perfect plasticity was confirmed for all the materials without exception. It was established that the compressive stress-strain diagram is described by a parabola fully determined by three fundamental constants, viz., yield point, maximal stress, and the strain at which this is attained. It is shown that for plastic metals the stress-strain diagram for large strains can be predicted from two initial points of the curve, and also from the results of standard tensile tests.