Laser Welding of Shape Memory Alloys

187 Pages·2016·23.64 MB·English

by  João Oliveira

João Pedro de Sousa Oliveira
Mestre em Ciência e Engenharia de Materiais

Laser Welding of Shape Memory Alloys

Dissertação para obtenção do Grau de Doutor em
Ciência e Engenharia de Materiais

Orientador: Francisco Manuel Braz Fernandes
Professor Associado com Agregação
Faculdade de Ciências e Tecnologia
Universidade Nova de Lisboa

Co-orientador: Rosa Maria Mendes Miranda
Professora Associada com Agregação
Faculdade de Ciências e Tecnologia
Universidade Nova de Lisboa

Júri:

Presidente Prof. Doutor Rodrigo Ferrão de Paiva Martins
Arguentes Prof. Doutora Maria Teresa Freire Vieira
Prof. Doutor Altino de Jesus Roque Loureiro
Vogais Prof. Doutora Maria Luísa Coutinho Gomes de Almeida
Prof. Doutor Norman Zhou
Prof. Doutor Francisco Manuel Braz Fernandes
Prof. Doutora Rosa Maria Mendes Miranda
Prof. Doutor Rui Jorge Cordeiro Silva

Junho de 2016

João Pedro de Sousa Oliveira
Mestre em Ciência e Engenharia de Materiais

Laser Welding of Shape Memory Alloys

Dissertação para obtenção do Grau de Doutor em
Ciência e Engenharia de Materiais

Orientador: Francisco Manuel Braz Fernandes
Professor Associado com Agregação
Faculdade de Ciências e Tecnologia
Universidade Nova de Lisboa

Co-orientador: Rosa Maria Mendes Miranda
Professora Associada com Agregação
Faculdade de Ciências e Tecnologia
Universidade Nova de Lisboa

Júri:

Presidente Prof. Doutor Rodrigo Ferrão de Paiva Martins
Arguentes Prof. Doutora Maria Teresa Freire Vieira
Prof. Doutor Altino de Jesus Roque Loureiro
Vogais Prof. Doutora Maria Luísa Coutinho Gomes de Almeida
Prof. Doutor Norman Zhou
Prof. Doutor Francisco Manuel Braz Fernandes
Prof. Doutora Rosa Maria Mendes Miranda
Prof. Doutor Rui Jorge Cordeiro Silva

Junho de 2016

Laser Welding of Shape Memory Alloys

Copyright © João Pedro de Sousa Oliveira, Faculdade de Ciências e Tecnologia, Universidade
Nova de Lisboa.

A Faculdade de Ciências e Tecnologia e a Universidade Nova de Lisboa têm o direito, perpétuo
e sem limites geográficos, de arquivar e publicar esta dissertação através de exemplares
impressos reproduzidos em papel ou de forma digital, ou por qualquer outro meio conhecido
ou que venha a ser inventado, e de a divulgar através de repositórios científicos e de admitir a
sua cópia e distribuição com objectivos educacionais ou de investigação, não comerciais, desde
que seja dado crédito ao autor e editor.

To my parents

If at first you don’t succeed you try and try again

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Acknowledgements
Along this path that ends with the writing of this document I crossed myself with several people
which, one way or the other, had some influence to the out coming results here presented.
First I must thank my supervisors, Professor Francisco Braz Fernandes and Professor Rosa
Miranda, who have accepted to enter this adventure, which started by applying for a scholarship
from the Portuguese Foundation for Science and Technology.
To Professor Braz Fernandes I thank for the numerous hours spent with me for discussion of
results and for always be available to discuss matters non-related with my work, which arise
from my scientific curiosity.
To Professor Rosa Miranda, always available to present ways to improve the work and for the
countless hours arguing with me about my work and other non-related situations. Additionally,
her expertise in welding technologies was fundamental to me throughout this work. I will not
forget her support during my stay in Canada when the experimental procedure appeared not to
work either way I tried.
To both Professor Braz Fernandes and Professor Rosa Miranda I express my gratitude for trusting
me their students, which I was allowed to co-supervise with them. Also, they allowed me to go
after different scientific interests which I came across during my thesis.
To Professor Norman Zhou, director of the Center for Advanced Materials Joining of the
University of Waterloo, Canada, I thank him to open his micro joining lab for me and for
providing me all the required means to successfully achieve all the purposed tasks.
During my at the University of Waterloo I meet other people which had significant importance
in this work. I will always be grateful to my friend Boyd Panton for his help in the laser welding
experiments and for our discussions regarding our works. To Zhi Zeng, another colleague, for his
help and insights on the best way to optimize the welding procedure. Additionally, I must thank
both Boyd and Zhi for trusting me to give them support for their experiments. To Carmen Andrei
from the Brockhouse Institute for Material Research at McMaster University for the useful
discussions during the transmission electron microscopy measurements.
I also must acknowledge Professor Jose Luis Ocaña, director of the Centro Laser of Universidad
Politécnica de Madrid for his availability and support during the similar laser welding trials of
NiTi. At the Centro Laser, during welding experiments, the technical support provided by Alberto
Cuesta and Alejandro Tur Gil was very welcomed.
Synchrotron X-ray diffraction was deeply used during this work. I acknowledge Dr. Norbert Schell
for his availability to receive us at Deutsche Electron Synchrotron (DESY) and for his technical
support during the experiments.
I also want to thank to André Cavaleiro for his help during the beam times at the DESY
synchrotron. We spent several long nights discussing results for our works. Additionally, his
useful scripts were very appreciated to facilitate data analysis.
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To my friend and colleague Patrícia Freitas for always be the positive person in our lab.
I acknowledge also the technical support by the staff of the Mechanical and Industrial
Engineering Department of Faculdade de Ciências e Tecnologias, Universidade Nova de Lisboa,
Portugal, for their help.
Financial support provided by Fundação para a Ciência e Tecnologia, under PhD grant
SFRH/BD/85047/2012 is acknowledged as well as support from Project No 612585 “MIDAS—
Micro and Nanoscale Design of Thermally Actuating Systems” Marie Curie Actions, FP7-PEOPLE-
2013-IRSES
To Professor Toshihiro Omori, from the Tokohu University, Japan, I’m grateful for providing the
superelastic Cu-Al-Mn alloy used in this work and for his useful indications during writing of the
related papers.
To Professor Luca Lutterotti, from Università degli Studi di Trento, Italia, developer of MAUD for
his useful tips for determining the residual stresses from synchrotron data.
To Professor Teresa Vieira, from Universidade de Coimbra, Portugal, for her suggestions as a
member of the advisory board of this thesis.
I have to thank also to my parents, Maria and Jorge, for all their love and support throughout
the years. Without them I wouldn’t be here, that is for sure.
Finally, but not least, I must express my gratitude towards Susana. For her love and
companionship, for her everlasting support, for dealing with my exquisite schedules, for really
understand my ambitions and to always be there for me when I need to even if there is an ocean
between the two of us. If that is not true love, I don’t know what it is then.
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