Recrystallization processing of additively-manufactured oxide dispersion strengthened Ni alloys

This study investigates the recrystallization behaviors of an additively manufactured oxide dispersion-strengthened (ODS) alloy during post-process heat treatments, with the intention of increasing the grain size for high-temperature creep resistance. ODS Ni–20Cr-0.4Y2O3 (wt.%) specimens prepared th...

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Bibliographic Details
Main Authors: Timothy Stubbs, Wenyuan Hou, Abdel Moustafa, Sam Gao, Yang Liu, Christopher P. Carter, Yuman Zhu, Zachary C. Cordero, Aijun Huang
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425012657
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Summary:This study investigates the recrystallization behaviors of an additively manufactured oxide dispersion-strengthened (ODS) alloy during post-process heat treatments, with the intention of increasing the grain size for high-temperature creep resistance. ODS Ni–20Cr-0.4Y2O3 (wt.%) specimens prepared through laser-powder bed fusion were subjected to isothermal and directional recrystallization heat treatments, similar to those applied to wrought ODS alloys. Isothermal annealing resulted in recrystallization at 1300 °C, with optimized conditions achieving a maximum grain dimension of ∼200 μm along the build direction. Directional recrystallization parallel to the build direction further increased the longitudinal grain size to ∼400 μm. In both isothermal and directional recrystallization, Y2O3 reacts with Ni to form molten Ni5Y which wets the grain boundaries. We speculate that formation of this phase promotes grain growth but denudes the matrix of dispersoids as it sweeps through the material.
ISSN:2238-7854