Anisotropic fracture behavior of AZ31 magnesium alloy sheets as a function of the stress state and temperature

摘要

The paper aims at describing the fracture behavior of AZ31 magnesium alloy sheets as a function of the temperature, stress state, and rolling direction. To this aim, fracture tests were carried out at room temperature, 100 degrees C and 300 degrees C using different specimen geometries cut at different orientations with respect to the sheet rolling direction. The fracture strain values were measured making use of the Digital Image Correlation (DIC) approach and the fracture surfaces qualitatively characterized by means of stereoscopy and Scanning Electron Microscopy (SEM). Afterwards, the AZ31 fracture locus as a function of the stress state, temperature and rolling direction was constructed. To analytically predict the fracture locus, a temperature-dependent parameter was added to the Modified Mohr Coulomb (MMC) fracture criterion; the newly proposed criterion was calibrated on the basis of the experimental data obtained from the tests previously mentioned, proving to be suitable to predict the AZ31 fracture locus for tension-dominated regions at varying temperature.