Compression-Induced Ductile Flow of Brittle Materials and Brittle Fracturing of Ductile Materials.

摘要

Even under all-around compressive loading, brittle materials tend to fail by the formation of tensile microcracks at microdefects such as cavities, grain boundaries, inclusions, and other inhomogeneities. As the overall confining pressure is increased, plastic flow tends to accompany microcracking, and eventually becomes the dominant mechanism of the overall deformation. Hence, under great confining pressure, brittle materials such as rocks can undergo large plastic flows before rupture. A most remarkable phenomenon, recently predicted analytically and verified experimentally, is that a very ductile material, such as pure copper or mild steel, when deformed inhomogeneously plastically in compression, can develop extensive tensile cracks normal to the applied compression and in the absence of any overall tensile loads. The article addresses the micromechanics of ductile flow of brittle materials and tensile fracturing of ductile materials under a broad range of compressive loads. (MM).