Crystallographic orientation-dependent deformation characteristics of additive manufactured interstitial-strengthened high entropy alloys
Wei Zhang, Jiajia Shen, J.P. Oliveira, Bart J. Kooi, Yutao Pei
Abstract
In this study, laser powder bed fusion (LPBF) was used for the fabrication of an interstitial-strengthened high entropy alloy (iHEA), Fe49.5Mn30Co10Cr10C0.5 (at.%). The as-fabricated iHEA possesses excellent strength-ductility synergy during tensile loading, with fracture strength reaching up to 1109 MPa at 37% engineering strain. Electron backscatter diffraction (EBSD) and high energy synchrotron X-ray diffraction were used to evaluate the microstructural characteristics of the material. In-situ EBSD analysis during uniaxial tensile testing was performed to unveil the deformation mechanisms. Moreover, crystallographic orientation-specific micropillar compression tests were conducted to determine how the grain deformation characteristics differ between orientations. Due to the activation of multiple slip systems and the homogeneous plastic flow, the [111] orientation demonstrated a higher yield strength and continuous work hardening rate. This research helps in clarifying grain orientation-specific contributions to the bulk mechanical response of additively manufactured HEA.