Comprehensive study on the formation of grain boundary serrations in additively manufactured Haynes 230 alloyShow others and affiliations
2020 (English)In: Materials Characterization, ISSN 1044-5803, E-ISSN 1873-4189, Vol. 160, article id 110092Article in journal (Refereed) Published
Abstract [en]
Recently, grain boundary serrations have been introduced in conventionally processed Haynes 230 through a slow-cooling heat treatment. The aim of this work was to utilize these heat treatments to introduce serrations in additively manufactured (Laser Metal Deposition) Haynes 230. Contrary to expectations, serrations already formed during the fast-cooling of the Laser Metal Deposition process. Electron Backscatter Diffraction was used to elucidate the underlying phenomenon for the emergence of serrations during fast-cooling. As a result, a hypothesis regarding a new mechanism responsible for the formation of grain boundary serrations was formulated. Additionally, specific characteristics of the Laser Metal Deposition process have been identified. This includes a columnar-to-equiaxed transition (CET) for slower feed rates, leading to smaller grains despite lower cooling rates; the observation of an abrupt increase in grain growth for a raised solution annealing temperature; the fact that serrations hinder uncontrolled grain growth and finally that the LMD-process leads to a finer carbide morphology compared to conventional manufacturing methods, potentially leading to an increased precipitation strengthening effect.
Place, publisher, year, edition, pages
Elsevier, 2020. Vol. 160, article id 110092
Keywords [en]
Additive manufacturing, Laser metal deposition, Grain boundary serration, Superalloy, Haynes 230, EBSD
National Category
Manufacturing, Surface and Joining Technology
Research subject
Manufacturing Systems Engineering
Identifiers
URN: urn:nbn:se:ltu:diva-77902DOI: 10.1016/j.matchar.2019.110092ISI: 000519655300028Scopus ID: 2-s2.0-85077398171OAI: oai:DiVA.org:ltu-77902DiVA, id: diva2:1401976
Note
Validerad;2020;Nivå 2;2020-04-03 (alebob)
2020-02-282020-02-282025-04-17Bibliographically approved