@MastersThesis{Paes:2022:EsPaSo,
author = "Paes, Rodrigo Andrade",
title = "Estudo dos par{\^a}metros de soldagem a laser do Nb e Ti6Al4V com
posterior tratamento termoqu{\'{\i}}mico via
implanta{\c{c}}{\~a}o i{\^o}nica por imers{\~a}o em plasma",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2022",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2022-03-07",
keywords = "soldagem a laser, implanta{\c{c}}{\~a}o i{\^o}nica por
imers{\~a}o em plasma de nitrog{\^e}nio em alta temperatura,
ni{\'o}bio, liga Ti-6Al-4V, laser beam welding, high-temperature
nitrogen plasma-immersion ion implantation, niobium, Ti-6Al-4V
alloy.",
abstract = "Este trabalho prop{\~o}e metodologias para a soldagem
aut{\'o}gena com laser Yb:fibra em chapas de ni{\'o}bio
met{\'a}lico comercialmente puro e da liga Ti-6Al-4V, com 1,3 mm
e 2,0 mm de espessura, respectivamente. Realizou-se para ambos o
tratamento p{\'o}s-soldagem de implanta{\c{c}}{\~a}o
i{\^o}nica por imers{\~a}o em plasma de nitrog{\^e}nio em alta
temperatura (3IP-AT). Gerou-se cartas de processamento na soldagem
de cada material na faixa de aporte t{\'e}rmico entre 5 200 J/mm
e equa{\c{c}}{\~o}es para o dimensionamento geom{\'e}trico dos
respectivos cord{\~o}es de solda. Investigou-se a influ{\^e}ncia
do aporte t{\'e}rmico sobre a estrutura (macro e
microsc{\'o}pica) da zona fundida (ZF), forma{\c{c}}{\~a}o de
fases cristalogr{\'a}ficas, distribui{\c{c}}{\~a}o elementar
nesta regi{\~a}o e varia{\c{c}}{\~a}o de microdureza Vickers.
Ap{\'o}s o tratamento 3IP-AT, realizou-se
caracteriza{\c{c}}{\~o}es semelhantes nos cord{\~o}es de solda
em ambos os materiais tratados, sendo os resultados obtidos
comparados com os resultados pr{\'e}vios dos cord{\~o}es de
solda n{\~a}o-tratados. A investiga{\c{c}}{\~a}o estrutural dos
cord{\~o}es de solda demonstrou que a soldagem a laser pode
ocorrer por condu{\c{c}}{\~a}o e/ou por penetra{\c{c}}{\~a}o,
dependendo do aporte At empregado, influenciando diretamente a
geometria e a microestrutura da ZF. As an{\'a}lises por DRX
identificaram a forma{\c{c}}{\~a}o de fases de {\'o}xidos
est{\'a}veis para ambos os materiais, al{\'e}m de evidenciarem o
surgimento de tens{\~o}es residuais de natureza trativa e
compressiva. Al{\'e}m disso, as an{\'a}lises por EDS
evidenciaram uma concentra{\c{c}}{\~a}o significativa de
{\'a}tomos de O, indicando que a prote{\c{c}}{\~a}o gasosa
durante a soldagem deve ser otimizada para mitigar a
oxida{\c{c}}{\~a}o. Os ensaios de dureza Vickers identificaram
um aumento significativo dos n{\'{\i}}veis de dureza na ZF e na
zona termicamente afetada dos cord{\~o}es de solda em ambos os
materiais para todas as condi{\c{c}}{\~o}es de aporte
t{\'e}rmico investigadas. O tratamento 3IP-AT realizado se
mostrou eficaz na forma{\c{c}}{\~a}o das respectivas fases de
nitretos est{\'a}veis de cada material, alterando
significativamente a superf{\'{\i}}cie dos cord{\~o}es de solda
e a distribui{\c{c}}{\~a}o de dureza Vickers ao longo das
diferentes regi{\~o}es dos cord{\~o}es de solda analisados.
ABSTRACT: This work proposes methodologies for autogenous welding
with Yb:fiber laser on sheets of commercially pure metallic
niobium and Ti-6Al-4V alloy, with 1,3 mm and 2,0 mm thickness,
respectively. Furthermore, the post-welding treatment of
high-temperature nitrogen plasma-immersion ion implantation
(HT-PIII) was carried out for both materials. Thus, welding
process windows were generated in the heat input range between 5 -
200 J/mm and equations proposed for geometric dimensioning of the
respective weld beads. Later, the influence of heat input on the
structure (macro and microscopic) of the fusion zone (FZ),
formation of crystallographic phases, elementary distribution, and
Vickers microhardness variation was investigated. After the
HT-PIII treatment, similar characterizations were performed on the
weld beads of both treated materials, and the results obtained
were compared with the previous results of the untreated weld
beads. Structural investigation of the weld beads showed that
laser welding mode can occur by conduction and/or by deep
penetration, depending on the heat input used, directly
influencing the geometry and the microstructure of the resulting
FZ. XRD analyses identified the formation of stable oxide phases
for both materials, in addition to evidencing residual stresses of
compressive and tensile nature. Additionally, EDS analyses
indicated a significant concentration of O atoms, showing that gas
shielding during welding should be optimized to mitigate
oxidation. Vickers hardness tests identified a significant
increase in hardness levels in the FZ and the heataffected zone of
the weld beads of both materials for all heat input conditions
investigated. The HT-PIII treatment performed proved to be
effective in the formation of the respective stable nitride phases
of each material, significantly altering the surface of the weld
beads and the Vickers hardness distribution along the diverse
regions of the analyzed weld beads.",
committee = "Oliveira, Rog{\'e}rio de Moraes (presidente) and Mineiro, Sergio
Luiz (orientador) and Mello, Carina Barros and Oliveira, Aline
Capella de",
englishtitle = "Study of Nb and Ti6Al4V laser beam welding parameters with
subsequent thermochemical treatment via plasma-immersion ion
implantation",
language = "pt",
pages = "204",
ibi = "8JMKD3MGP3W34T/46GMN4B",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/46GMN4B",
targetfile = "publicacao.pdf",
urlaccessdate = "09 maio 2024"
}