STUDIES IN LARGE PLASTIC FLOW AND FRACTURE :With Special Emphasis on the Effects of Hydrostatic Pressure

In the course of experiments extending over many years on the effect of high hydrostatic pressure on the properties of matter, in which the pres- sures were often deliberately pushed to the breaking point of the con- tainers, I have had occasion to observe many fractures under unusual conditions. These fractures were often of an unanticipated nature and might be positively contrary to expectations based on engineering experi- ence in a lower range of stresses. At first my interest in these fractures was a secondary one, and I was mainly concerned with attempting to understand the phenomena only insofar as was necessary for the design of my pressure apparatus. With the accumulation of material, however, and in particular with the discovery of the enormous effect of hydrostatic pressure in increasing ductility and in extending the domain of strain- hardening in steel, my interest grew in the subject for its own sake. Many experiments were therefore made with the explicit purpose of understanding better the nature of both the phenomena of fracture under conditions of high stress and the phenomena of the large plastic flow which often precedes such fractures. A number of these investigations were made during the war with practical applications in mind. The wartime investigations raised other questions which were later pursued further for their own interest. In this book I present a coordinated exposition of all this experience under rather unusual conditions. I hope that, apart from any intrinsic interest, it may assist in leading to a better understanding of the difficult problems of flow and fracture, many of them still unsolved, in the narrower range of conditions more usually encountered in practical situations.