Microstructural and Mechanical Characterization of Directionally Solidified Conventional and Nb-Modified Mar-M247 Superalloy

dc.contributor.authorCosta, A. M.S.
dc.contributor.authorLopes, E. S.N.
dc.contributor.authorContieri, R. J.
dc.contributor.authorCaram, R.
dc.contributor.authorBaldan, R. [UNESP]
dc.contributor.authorFuchs, G. E.
dc.contributor.authorNunes, C. A.
dc.contributor.institutionMethodist University of Piracicaba
dc.contributor.institutionUniversidade Estadual de Campinas (UNICAMP)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniversity of Florida
dc.contributor.institutionUniversidade de São Paulo (USP)
dc.date.accessioned2019-10-06T16:26:09Z
dc.date.available2019-10-06T16:26:09Z
dc.date.issued2019-04-01
dc.description.abstractThis study analyzes the effects of replacing Ta by Nb (at.% basis) in the phase transformation temperatures, Scheil solidification behavior, and microstructural mechanical features of a Nb-modified as well as conventional Mar-M247 superalloys. Both alloys were directionally solidified at a withdrawal rate of 18 cm/h under a thermal gradient of about 80 °C/cm. DSC results were compared to thermodynamic simulations of phase transformation temperatures and showed a good correlation. The replacement of Ta by Nb has not altered the solidification path of Mar-M247, keeping the sequence L → L + γ → L + γ + MC → L + γ + MC + γ/γ′ eutectic. Due to the segregation of Hf and Zr to the very last liquid to solidify, a low melting point γ/Ni 5 (Hf,Zr) constituent was observed. The as-solidified microstructures of both Mar-M247(Nb) and Mar-M247 were constituted of columnar dendrites of gamma matrix (γ) phase with cuboidal gamma-prime (γ′) precipitates. In addition, γ/γ′-eutectic was observed in the interdendritic region along with MC carbides in blocky, script (blocky dendritic), needle-like and fine nodular morphologies. Both alloys contained about 1.5 vol.% of MC carbides. The MC carbides in Mar-M247(Nb) and Mar-M247 are, respectively, Nb-rich and Ta-rich, with only a limited amount of Hf being detected in the MC phase. The yield stress of Nb-modified Mar-M247 showed higher values up to 750 °C. For higher temperatures, above 800 °C, a conventional Mar-M247 presented a higher value of yield stress.en
dc.description.affiliationMethodist University of Piracicaba, R. Luis Ometto, Km 24
dc.description.affiliationSchool of Mechanical Engineering University of Campinas
dc.description.affiliationSchool of Applied Sciences University of Campinas
dc.description.affiliationSão Paulo State University (Unesp), Campus of Itapeva
dc.description.affiliationMaterials Science and Engineering Department University of Florida
dc.description.affiliationEscola de Engenharia de Lorena Universidade de Sao Paulo, Pólo Urbo-Industrial Gleba AI-6
dc.description.affiliationUnespSão Paulo State University (Unesp), Campus of Itapeva
dc.format.extent2427-2438
dc.identifierhttp://dx.doi.org/10.1007/s11665-019-04014-1
dc.identifier.citationJournal of Materials Engineering and Performance, v. 28, n. 4, p. 2427-2438, 2019.
dc.identifier.doi10.1007/s11665-019-04014-1
dc.identifier.issn1544-1024
dc.identifier.issn1059-9495
dc.identifier.lattes1514019536224632
dc.identifier.orcid0000-0003-4172-3689
dc.identifier.scopus2-s2.0-85064432015
dc.identifier.urihttp://hdl.handle.net/11449/188989
dc.language.isoeng
dc.relation.ispartofJournal of Materials Engineering and Performance
dc.rights.accessRightsAcesso aberto
dc.sourceScopus
dc.subjectMar-M247 superalloy
dc.subjectNb-modified Mar-M247
dc.subjectthermodynamic simulation
dc.titleMicrostructural and Mechanical Characterization of Directionally Solidified Conventional and Nb-Modified Mar-M247 Superalloyen
dc.typeArtigo
unesp.author.lattes1514019536224632[5]
unesp.author.orcid0000-0003-4172-3689[5]
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Ciências e Engenharia, Itapevapt
unesp.departmentEngenharia Industrial Madeireira - ICEpt

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