Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys

Detalhes bibliográficos
Autor(a) principal: Soares,Roniere Leite
Data de Publicação: 2019
Outros Autores: Castro,Walman Benício de
Tipo de documento: Artigo
Idioma: eng
Título da fonte: REM - International Engineering Journal
Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2019000300227
Resumo: Abstract High transformation temperature shape-memory alloys (HTSMA) usually present a martensitic transformation temperature (Ms) starting at 100 ºC. That is the case of high nickel Ni-Ti-Hf alloys. This article presents experimental results obtained from arc melting of Ni50Ti50-XHfX .at% (X = 8, 11, 14, 17 and 20 .at%) alloys. This process homogenized every composition with similar relative crystallinity. Results confirm that transformation temperatures (TT) increase with increasing the amount of Hf. A martensitic matrix is formed by two metastable phases: R and B19'. From all the alloys studied, the B19' phase presented the highest percent fraction. Gradually adding Hf3 .at% promoted a slow increase of crystalline fraction of R phase and a slow reduction of phase (Ti, Hf)2 Ni, located at grain boundaries. Coherent/semi-coherent interface between (Ti, Hf)2 Ni phase and the matrix may intensify the driving force for the formation of R phase, present on X-ray diffractograms.
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spelling Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloyshigh temperature shape memory alloysNi-Ti-Hf alloysmicrostructureAbstract High transformation temperature shape-memory alloys (HTSMA) usually present a martensitic transformation temperature (Ms) starting at 100 ºC. That is the case of high nickel Ni-Ti-Hf alloys. This article presents experimental results obtained from arc melting of Ni50Ti50-XHfX .at% (X = 8, 11, 14, 17 and 20 .at%) alloys. This process homogenized every composition with similar relative crystallinity. Results confirm that transformation temperatures (TT) increase with increasing the amount of Hf. A martensitic matrix is formed by two metastable phases: R and B19'. From all the alloys studied, the B19' phase presented the highest percent fraction. Gradually adding Hf3 .at% promoted a slow increase of crystalline fraction of R phase and a slow reduction of phase (Ti, Hf)2 Ni, located at grain boundaries. Coherent/semi-coherent interface between (Ti, Hf)2 Ni phase and the matrix may intensify the driving force for the formation of R phase, present on X-ray diffractograms.Fundação Gorceix2019-06-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2019000300227REM - International Engineering Journal v.72 n.2 2019reponame:REM - International Engineering Journalinstname:Fundação Gorceix (FG)instacron:FG10.1590/0370-44672018720072info:eu-repo/semantics/openAccessSoares,Roniere LeiteCastro,Walman Benício deeng2019-03-19T00:00:00Zoai:scielo:S2448-167X2019000300227Revistahttps://www.rem.com.br/?lang=pt-brPRIhttps://old.scielo.br/oai/scielo-oai.php||editor@rem.com.br2448-167X2448-167Xopendoar:2019-03-19T00:00REM - International Engineering Journal - Fundação Gorceix (FG)false
dc.title.none.fl_str_mv Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
title Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
spellingShingle Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
Soares,Roniere Leite
high temperature shape memory alloys
Ni-Ti-Hf alloys
microstructure
title_short Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
title_full Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
title_fullStr Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
title_full_unstemmed Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
title_sort Effects of composition on transformation temperatures and microstructure of Ni-Ti-Hf shape memory alloys
author Soares,Roniere Leite
author_facet Soares,Roniere Leite
Castro,Walman Benício de
author_role author
author2 Castro,Walman Benício de
author2_role author
dc.contributor.author.fl_str_mv Soares,Roniere Leite
Castro,Walman Benício de
dc.subject.por.fl_str_mv high temperature shape memory alloys
Ni-Ti-Hf alloys
microstructure
topic high temperature shape memory alloys
Ni-Ti-Hf alloys
microstructure
description Abstract High transformation temperature shape-memory alloys (HTSMA) usually present a martensitic transformation temperature (Ms) starting at 100 ºC. That is the case of high nickel Ni-Ti-Hf alloys. This article presents experimental results obtained from arc melting of Ni50Ti50-XHfX .at% (X = 8, 11, 14, 17 and 20 .at%) alloys. This process homogenized every composition with similar relative crystallinity. Results confirm that transformation temperatures (TT) increase with increasing the amount of Hf. A martensitic matrix is formed by two metastable phases: R and B19'. From all the alloys studied, the B19' phase presented the highest percent fraction. Gradually adding Hf3 .at% promoted a slow increase of crystalline fraction of R phase and a slow reduction of phase (Ti, Hf)2 Ni, located at grain boundaries. Coherent/semi-coherent interface between (Ti, Hf)2 Ni phase and the matrix may intensify the driving force for the formation of R phase, present on X-ray diffractograms.
publishDate 2019
dc.date.none.fl_str_mv 2019-06-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2019000300227
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2448-167X2019000300227
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/0370-44672018720072
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv text/html
dc.publisher.none.fl_str_mv Fundação Gorceix
publisher.none.fl_str_mv Fundação Gorceix
dc.source.none.fl_str_mv REM - International Engineering Journal v.72 n.2 2019
reponame:REM - International Engineering Journal
instname:Fundação Gorceix (FG)
instacron:FG
instname_str Fundação Gorceix (FG)
instacron_str FG
institution FG
reponame_str REM - International Engineering Journal
collection REM - International Engineering Journal
repository.name.fl_str_mv REM - International Engineering Journal - Fundação Gorceix (FG)
repository.mail.fl_str_mv ||editor@rem.com.br
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