Hydrogen partitioning behavior and hydrogen embrittlement in Al-Zn-Mg alloys

Abstract

The growth of micropores, the nucleation of voids, and the crack initiation/propagation with hydrogen embrittlement are phenomena that are competitive during fracture. These complex phenomena can be evaluated using the synchrotron X-ray tomography. In the present study, high-Zn Al-Zn-Mg alloys were prepared, and in-situ tensile test along with synchrotron X-ray tomography was performed. As a result, the fracture mode has changed to the quasi-cleavage fracture by accumulating hydrogen in a flow-localized region. Moreover, characteristic volume expansion was observed in this region. It has been clarified that this volume expansion was dominated with free-volume (i.e. vacancycluster, nano voids) formation according to the 3D strain mapping.