Reorganization of the microstructure gradient after uniaxial micro-tensile testing on thin wall Inconel 718 printed by laser powder bed fusion

In this paper, the microstructure of the additively manufactured Inconel 718 was characterized by using enhanced Back-Scattered Electrons and Electron Back Scattered Diffraction. Precipitates were observed in the interdentritic and grain boundary region with respect to the layer-by-layer process. The chemical composition of the different precipitates was identified using Scanning Electron Microscopy coupled with energy-dispersive spectroscopy. A microstructural gradient divided into three regions from the border to the volume was observed with different grain shapes and grain sizes, induced by the rapid solidification and cooling rate. During ex situ micro- tensile testing, a reorganization of the microstructure of the Inconel 718 printed in ZX (vertical) and XY (horizontal) building directions was observed. Under the uni-axial tensile loading for ZX building direction, grain rotation as well as grain boundary migration were observed. This work highlighted the peculiar evolution of the microstructural gradient for Inconel 718 build in Inconel 718 in ZX building direction.