Analysis of the high cracking resistance of a Co Ni superalloy during laser additive manufacturing

TitleAnalysis of the high cracking resistance of a Co Ni superalloy during laser additive manufacturing
Publication TypeJournal Article
Year of Publication2024
AuthorsLamb J, Pusch KM, Polonsky AT, Forsik SAJ, Zhou N, Dicus AD, Geurts R, Echlin MLP, Pollock TM
JournalScripta Materialia
Volume239
Pagination115770
ISSN1359-6462
Keywords3D EBSD, Rapid solidification, Superalloy
Abstract

A newly developed CoNi-based superalloy is demonstrated to be tolerant of a wide range of laser powder bed fusion print conditions, with limited defect content and high relative densities. These promising traits motivated investigation of the structural uniformity in samples printed at the upper end of the scan velocity processing window (>Image 1). A new misorientation metric, starting reference orientation deviation (SROD), was calculated from Image 2-scale 3D microstructure information to examine structure evolution during epitaxial growth of columnar grains. Misorientations of >20° were observed within the large columnar grains that grew through multiple build layers. The SROD observations highlight the CoNi superalloy's ability to plastically deform to high levels, as evidenced by misorientation gradients, across the range of temperatures experienced in laser additive manufacturing. Misorientation gradients within the columnar grain structure are high relative to Ni base superalloys, allowing for strengthening with high volume fractions of L12 precipitates.

URLhttps://www.sciencedirect.com/science/article/pii/S1359646223004918
DOI10.1016/j.scriptamat.2023.115770