@article {2206,
	title = {Analysis of the high cracking resistance of a Co Ni superalloy during laser additive manufacturing},
	journal = {Scripta Materialia},
	volume = {239},
	year = {2024},
	pages = {115770},
	abstract = {<p>
	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 (\&gt;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 \&gt;20\&deg; were observed within the large columnar grains that grew through multiple build layers. The SROD observations highlight the CoNi superalloy\&$\#$39;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.
</p>
},
	keywords = {3D EBSD, Rapid solidification, Superalloy},
	issn = {1359-6462},
	doi = {https://doi.org/10.1016/j.scriptamat.2023.115770},
	url = {https://www.sciencedirect.com/science/article/pii/S1359646223004918},
	author = {James Lamb and Kira M. Pusch and Andrew T. Polonsky and St{\'e}phane A.J. Forsik and Ning Zhou and Austin D. Dicus and Remco Geurts and McLean P. Echlin and Tresa M. Pollock}
}
@article {2211,
	title = {Rapid Screening of Single Phase Refractory Alloys Under Laser Melting Conditions},
	journal = {Materials \& Design},
	year = {2024},
	pages = {112726},
	abstract = {<p>
	Refractory alloys can be difficult to fabricate by laser-based manufacturing methods due to their high melting temperatures, high interstitial solubility, and propensity for low temperature brittleness. Laser-based processes, such as welding and additive manufacturing (AM), yield similar populations of defects, including microsegregation and solidification and solid-state cracking. Given the extreme challenges and cost associated with the production of refractory powders, this research aimed to develop a rapid screening methodology that combines predictive defect formation metrics with single track melting experiments. A flexible single laser track melting platform was designed to perform screening experiments on conventional and multi-principal element refractory alloys across a wide range of laser energy inputs. The platform was employed to investigate laser melting on solid substrates, or on a substrate with a single layer of powder feedstock, and is demonstrated with the highly fabricable Nb-base alloy C103. Preliminary investigations are performed on refractory multi-principal element alloys in the Hf-Mo-Nb-Ta-Ti family, and significant differences in cracking resistance and solidification morphology are observed. Implications for future alloy design and processing strategies for defect-resistant refractory alloys for AM are discussed.
</p>
},
	keywords = {Additive manufacturing, high entropy alloy, multi-principal element alloy, refractory alloys, solid-state cracking, solidification cracking},
	issn = {0264-1275},
	doi = {https://doi.org/10.1016/j.matdes.2024.112726},
	url = {https://www.sciencedirect.com/science/article/pii/S0264127524000984},
	author = {Kaitlyn M. Mullin and Carolina Frey and James Lamb and Sophia K. Wu and McLean P. Echlin and Tresa M. Pollock}
}
