Voiding and fracture in high-entropy alloy under multi-axis stress states

In situ scanning electron microscope (SEM) investigation is carried out on high-entropy alloy (HEA) specimen with various geometries to realize the multi-axial stress states. The dimple structure on the fracture surface is quantified and the nucleation of void is examined. The deformation twins can provide more sites for void nucleation and constrain shape change of the voids. Even under the low stress-triaxiality, the void can coalesce to reach large size accompanying twinning. The evolution of void size and density deduced from the fractograph is important to quantify ductile fracture of HEA. (C) 2018 Elsevier B.V. All rights reserved.