Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu
The study, selection and feasibility of non-toxic alloys for soldering electronic microcomponents are urgent and necessary demands in a context of accelerated technological advancement and Industry 4.0. Alternative lead-free solder alloys such as Sn-Ag-Cu (SAC) system alloys have stood out for th...
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Solidificação Ligas Sn-Ag-Cu Microestrutura Laser Corrosão CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA |
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Solidificação Ligas Sn-Ag-Cu Microestrutura Laser Corrosão CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA Xavier, Amanda Rávilla Valério Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| description |
The study, selection and feasibility of non-toxic alloys for soldering electronic
microcomponents are urgent and necessary demands in a context of accelerated
technological advancement and Industry 4.0. Alternative lead-free solder alloys such as
Sn-Ag-Cu (SAC) system alloys have stood out for this application, as they have good
wettability on metallic substrates, high creep strength and melting temperature close to
the eutectic Sn-37wt.%Pb alloy, traditionally used in these situations. Laser surface
treatments result in significant microstructural changes, but studies for Sn-based alloys
are scarce in the literature. In this sense, the present research aims to understand the
microstructural characteristics and the respective hardness of the Sn-1wt.%Ag0.7wt.%Cu (SAC107) and Sn-3wt.%Ag-0.7wt.%Cu (SAC307) alloys treated by Laser
Surface Remelting (LSR). The corrosion resistances of the as-cast samples of SAC107
and SAC307 alloys have also been analyzed. In order to understand the solidification
paths of the alloys, such as solidification interval and transformation temperatures,
thermodynamic calculations were performed via the Thermo-Calc software.
Microstructural characterization was performed using optical microscopy (OM),
scanning electron microscopy (SEM) and the Electron Backscatter Diffraction (EBSD)
technique. The corrosion tests were made possible by potentiodynamic polarization, in
addition to the Vickers microhardness tests. The increase in Ag content slightly reduced
the liquidus temperature (TL), not changing the solidus (TS) and eutectic (TE)
temperatures. As-cast microstructures are composed of Sn-rich dendrites surrounded by
a ternary eutectic mixture β-Sn+Ag3Sn+Cu6Sn5. An epitaxial growth has been observed
at the base of the Laser remelted pools, as well as a significant microstructure
refinement in relation to the microstructural scale of the substrate (as-cast), of 98.5%
and 99.4%, for the SAC107 and SAC307 alloys, respectively, associated at cooling rates
of the order of 102
°C/s. Microhardness increases of 64.35% and 67.35% were noted for
SAC107 and SAC307 alloys, respectively, from coarse microstructures to refined
microstructures obtained by Laser. The polarization curves showed a more active
behavior of samples with coarser microstructures for both SAC alloys. SAC307 alloy
exhibited greater corrosion resistance than SAC107 alloy. |
| author2 |
Silva, Bismarck Luiz |
| author_facet |
Silva, Bismarck Luiz Xavier, Amanda Rávilla Valério |
| format |
masterThesis |
| author |
Xavier, Amanda Rávilla Valério |
| author_sort |
Xavier, Amanda Rávilla Valério |
| title |
Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| title_short |
Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| title_full |
Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| title_fullStr |
Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| title_full_unstemmed |
Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu |
| title_sort |
corrosão e refusão superficial à laser de ligas sn-ag-cu |
| publisher |
Universidade Federal do Rio Grande do Norte |
| publishDate |
2023 |
| url |
https://repositorio.ufrn.br/handle/123456789/52289 |
| work_keys_str_mv |
AT xavieramandaravillavalerio corrosaoerefusaosuperficialalaserdeligassnagcu |
| _version_ |
1773966216886484992 |
| spelling |
ri-123456789-522892023-05-09T20:04:37Z Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu Xavier, Amanda Rávilla Valério Silva, Bismarck Luiz http://lattes.cnpq.br/9606841256778456 http://lattes.cnpq.br/4377238190630005 Bertelli, Felipe Peres, Maurício Mhirdaui http://lattes.cnpq.br/3068024292581677 Solidificação Ligas Sn-Ag-Cu Microestrutura Laser Corrosão CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA The study, selection and feasibility of non-toxic alloys for soldering electronic microcomponents are urgent and necessary demands in a context of accelerated technological advancement and Industry 4.0. Alternative lead-free solder alloys such as Sn-Ag-Cu (SAC) system alloys have stood out for this application, as they have good wettability on metallic substrates, high creep strength and melting temperature close to the eutectic Sn-37wt.%Pb alloy, traditionally used in these situations. Laser surface treatments result in significant microstructural changes, but studies for Sn-based alloys are scarce in the literature. In this sense, the present research aims to understand the microstructural characteristics and the respective hardness of the Sn-1wt.%Ag0.7wt.%Cu (SAC107) and Sn-3wt.%Ag-0.7wt.%Cu (SAC307) alloys treated by Laser Surface Remelting (LSR). The corrosion resistances of the as-cast samples of SAC107 and SAC307 alloys have also been analyzed. In order to understand the solidification paths of the alloys, such as solidification interval and transformation temperatures, thermodynamic calculations were performed via the Thermo-Calc software. Microstructural characterization was performed using optical microscopy (OM), scanning electron microscopy (SEM) and the Electron Backscatter Diffraction (EBSD) technique. The corrosion tests were made possible by potentiodynamic polarization, in addition to the Vickers microhardness tests. The increase in Ag content slightly reduced the liquidus temperature (TL), not changing the solidus (TS) and eutectic (TE) temperatures. As-cast microstructures are composed of Sn-rich dendrites surrounded by a ternary eutectic mixture β-Sn+Ag3Sn+Cu6Sn5. An epitaxial growth has been observed at the base of the Laser remelted pools, as well as a significant microstructure refinement in relation to the microstructural scale of the substrate (as-cast), of 98.5% and 99.4%, for the SAC107 and SAC307 alloys, respectively, associated at cooling rates of the order of 102 °C/s. Microhardness increases of 64.35% and 67.35% were noted for SAC107 and SAC307 alloys, respectively, from coarse microstructures to refined microstructures obtained by Laser. The polarization curves showed a more active behavior of samples with coarser microstructures for both SAC alloys. SAC307 alloy exhibited greater corrosion resistance than SAC107 alloy. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES O estudo, a seleção e a viabilização de ligas não tóxicas para brasagem de microcomponentes eletrônicos são demandas urgentes e necessárias em um contexto de avanço tecnológico acelerado e da Indústria 4.0. Ligas alternativas livres de chumbo como as ligas do sistema Sn-Ag-Cu (SAC) tem se destacado para esta aplicação, pois apresentam boa molhabilidade em substratos metálicos, alta resistência à fluência e temperatura de fusão próxima à liga eutética Sn-37%Pb, tradicionalmente utilizadas nestas situações. Tratamentos superficiais à Laser resultam em mudanças microestruturais significantes, mas estudos para ligas à base de Sn são escassos na literatura. Neste sentido, a presente pesquisa visa compreender as características microestruturais e as respectivas durezas das ligas Sn-1%Ag-0,7%Cu (SAC107) e Sn3%Ag-0,7%Cu (SAC307) tratadas por refusão superficial à Laser (RSL). As resistências à corrosão de amostras brutas de solidificação das ligas SAC107 e SAC307 também têm sido analisadas. A fim de compreender os caminhos de solidificação das ligas, tais como intervalo de solidificação e temperaturas de transformação, foram realizados cálculos termodinâmicos via o software Thermo-Calc. A caracterização microestrutural foi realizada via microscopia ótica (MO), microscopia eletrônica de varredura (MEV) e a técnica de Difração de Elétrons Retro-Espalhados (EBSD). Os testes de corrosão foram viabilizados por polarização potenciodinâmica, além dos ensaios de microdureza Vickers. O aumento do teor de Ag reduziu ligeiramente a temperatura liquidus (TL), não alterando as temperaturas solidus (TS) e eutética (TE). As microestruturas brutas de solidificação são compostas de dendritas ricas em Sn circundadas por uma mistura eutética ternária β-Sn+Ag3Sn+Cu6Sn5. Um crescimento epitaxial tem sido observado na base das poças refundidas à Laser, assim como um refino da microestrutura significativo em relação à escala microestrutural do substrato (bruto de fusão), de 98,5% e 99,4%, para as ligas SAC107 e SAC307, respectivamente, associados às taxas de resfriamento da ordem de 102 °C/s. Aumentos de dureza de 64,35% e 67,35% foram notados para as ligas SAC107 e SAC307, respectivamente, das microestruturas grosseiras para as microestruturas refinadas obtidas por Laser. As curvas de polarização evidenciaram um comportamento mais ativo das amostras com microestruturas mais grosseiras para ambas as ligas SAC. A liga SAC307 exibiu maior resistência à corrosão que a liga SAC107. 2023-05-09T20:03:32Z 2023-05-09T20:03:32Z 2022-09-29 masterThesis XAVIER, Amanda Rávilla Valério. Corrosão e refusão superficial à laser de ligas Sn-Ag-Cu. Orientador: Bismarck Luiz Silva. 2022. 112f. Dissertação (Mestrado em Ciência e Engenharia de Materiais) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2022. https://repositorio.ufrn.br/handle/123456789/52289 pt_BR Acesso Aberto application/pdf Universidade Federal do Rio Grande do Norte Brasil UFRN PROGRAMA DE PÓS-GRADUAÇÃO EM CIÊNCIA E ENGENHARIA DE MATERIAIS |