AN EXPERIMENTAL STUDY OF DUCTILE FAILURE UNDER MULTI-AXIAL LOADING.

Recent experimental investigations show that most models are not able to capture the ductile behavior of metal alloys in the entire triaxiality range, especially at low triaxiality. Modelers are moving beyond stress triaxiality as the dominant indicator of material failure and developing constitutive models that incorporate shear into the evolution of the failure model. Available data that cover low triaxiality range are rare and a series of critical experiments is needed. Here, experiments of smooth thin as well as notched tubular specimens of Al6061-T651 under combined tension-torsion loading were conducted. This provides a very basic set of data for phenomenological models. A full-field deformation technique, digital image correlation (DIC), was applied to these tests to allow measurement of the field deformation, including the notched area. The microstructural features of the tested specimens were characterized to better understand the different failure mechanisms which led to ductility variation in the aluminum alloy.Copyright © 2014 by ASME