On the Spatial Variation of the Microstructure and Microhardness Properties of Nickel-Based Superalloy René 142 Fabricated via Scanning Laser Epitaxy (SLE)

Abstract This article seeks to investigate and characterize the spatial variation of the microstructure and microhardness properties of René 142, a high-γ′ nickel-based superalloy, fabricated through single-pass depositions using scanning laser epitaxy (SLE), a laser powder bed fusion (LPBF)–based additive manufacturing (AM) process. Various advanced material characterization techniques such as optical microscopy, scanning electron microscopy, and Vickers microhardness measurements are employed to thoroughly characterize the SLE-fabricated René 142 specimens. Whereas optical microscopy analyses reveal that the primary dendritic arm spacing (PDAS) remains relatively constant, scanning electron microscopy investigations demonstrate that the size of the γ′ precipitates increase as the scan progresses. Microhardness measurements indicate that the hardness values remain unaffected along the scan direction. Through this study, it is demonstrated that the microstructure and the microhardness properties of the AM-fabricated René 142 deposits are strong functions of the spatial location.