Shear-Dominated Fracture of Ductile Metal Under Mixed Loading and Preliminary Assessment

At room temperature, fracture of ductile metal often appears ductile, which is thought as the result of nucleation, dilatation and coalescence of microvoids in material. The remnant of microvoids in fracture surface is dimple. Dimple-mode fracture (void-dominated) is often accompanied with dilatation of volume of loaded material [1–4]. Fracture not accompanied with dilatation of volume was often studied at low temperature. Researchers think that the modes and mechanisms of fracture are affected by temperature and when temperature decreases ductile fracture becomes brittle fracture. No-volume-dilatation fracture is often related with low temperature fracture or brittle material’s fracture. But at room temperature, there is also no-volume-dilatation fracture, i.e., shear fracture of ductile material. There are very large differences between brittle fracture and shear fracture of ductile material, in which the deformation may be considerably larger before collapse [5]. Yamamoto [6] thought that heterogeneity of material resulted in local shear band in which there were lots of microvoids, and this led to fracture. Yang and Lee [7] described analogous process of initiation of fraction in their work. They indeed attributed shear fracture of ductile material to evolution of microvoids. In this presentation, instead of explaining shear-dominated fracture of ductile material as the result of evolution of microvoids, shear-dominated fracture of ductile metal is thought to be due to another mesomechanism, micro-shear-band. Some experiment results and simulation of finite element method of shear-dominated fracture of ductile metal are given. A kind of preliminary assessment about shear-dominated fracture of ductile material is proposed.© 2004 ASME