Plastic Deformation of Polycrystalline Metals Subjected to Cycle of Stress

Abstract

It is the aim of the present study to elucidate the plastic deformation of polycrystalline metals, consequent on the cycle of stress to which the material was subjected, with respect to its strain history, as part of the series of studies to be made on the influence of strain history on the plastic deformation of polycrystalline metals. It will be considered that the aggregate plastic deformation of the material subjected to low cycle of stress is to be mainly interpreted from redistribution of stress field in the material. The experimental examination of this proposition was made by using the strain measurement apparatus specially designed. From the present analytical and experimental studies on low carbon steel at room temperature, the following conclusion has been made.(1) The yield function of Eqs. (1) and (2) is adaptable to the representation of shape of yield surface of the material under cyclic stressing.(2) The plastic deformation mechanism of polycrystalline metals under a cycle of stress is interpreted from an assemblage of single models as shown in Fig. 3.(3) The cycle-dependent plastic deformation occurs in a different manner of each part of the test specimen, because of the difference in each part of the material structure and its structural change during the stress cycle. It is to be ascribed to the anisotropy of the material, to Bauschinger effect and also to redistribution of yield stress of each part of the structural element.