FAILURE MAPS APPLIED TO METAL DEFORMATION PROCESSES

In describing the failure of metals in forming operations, it is necessary to consider both the operative state of stress and the mechanism of failure in relation to the micro structure. An experimental program has been conducted to measure the strain to failure for various aluminum alloys subject to different loading paths. If it is assumed that the strain history to failure can be described by a sequence of proportional straining and plane strain deformation the fracture condition for any loading path can be expressed either in stress or strain space in the form of a fracture map, the shape of which depends on the fracture mode. This formalism has been used to compare fracture in various materials and microstructural conditions, to illustrate empirical failure criteria and to develop failure criteria for multi-axial loading.