Vis enkel innførsel

dc.contributor.advisorStrandlie, Are
dc.contributor.advisorMarthinsen, Knut
dc.contributor.advisorNinive, Per Harald
dc.contributor.advisorFriis, Jesper
dc.contributor.authorKhalid, Muhammad Zeeshan
dc.date.accessioned2021-01-04T16:01:43Z
dc.date.available2021-01-04T16:01:43Z
dc.date.issued2020
dc.identifier.isbn978-82-326-4525-1
dc.identifier.issn1503-8181
dc.identifier.urihttps://hdl.handle.net/11250/2721346
dc.description.abstractThe joining of aluminum and steel has been considered an efficient solution for building light-weight technology, particularly in the automotive, aerospace and shipbuilding industries. It is an immense challenge to join these materials together due to the significant differences in the physical and chemical properties of aluminum and steel. The development of intermetallic compound (IMC) layers has a huge impact on the strength of the aluminum-steel joint. The development of IMCs at the aluminum and steel joint is greatly influenced by the welding methodology and temperature reached during the welding process. It is thermodynamically possible to develop certain IMCs depending on the composition and phase diagram of aluminum and steel alloys. For this reason, understanding the mechanical nature of the IMCs is pivotal to improve the welding methodologies. In this work, atomistic simulations were performed on Fe2Al5, Fe4Al13 and α-AlFeSi bulk and interface structures. We started with the construction of atomistic bulk structures of Fe2Al5 and Fe4Al13 and calculated the mechanical properties using density functional theory (DFT) calculations. A comparative study was performed to identify the mechanical behavior of these compounds. Moreover, comparisons were also made with other experimental, semi-empirical and ab-initio methods to test the reliability of the calculations. Due to the complex nature and large atomic structures of Fe-Al IMCs, using ab-initio methods could be very computationally expensive. To make computational calculations fast and accurate, a semi-empirical potential based method has also been used in this work. The main objective of this study was to test the reliability of modified embedded atoms method (MEAM) potentials and suitability for finding good initial structures for Fe-Al interfaces. It was concluded that MEAM and semi-empirical methods are not reliable for inferring mechanical features of Fe-Al IMCs. However, MEAM was found to be reasonable for finding good initial guesses for the Fe-Al interface structures. Lastly, a systematic study was performed to identify the virtual tensile and shear strengths of Fe-Al and α-AlFeSi interfaces using DFT. Interface structures were optimized using the fast inertial relaxation engine (FIRE), which was very successful in optimizing these complex interfaces with a large number of atoms. After the optimization of the interface structures, virtual tensile and shear strength calculations were performed. An extended version of the so-called Universal Binding Energy relation (UBER) was used to fit the energy-displacement curve for virtual tensile strength and a Fourier series for the virtual shear strength predictions. The results indicated the potential negative effect of the Fe-Al IMCs on the strengths of the aluminum-steel joint.en_US
dc.language.isoengen_US
dc.publisherNTNUen_US
dc.relation.ispartofseriesDoctoral theses at NTNU;2020:86
dc.relation.haspartPaper 1: Khalid, Muhammad Zeeshan; Friis, Jesper; Ninive, Per Harald; Marthinsen, Knut; Strandlie, Are. DFT calculations based insight into bonding character and strength of Fe2Al5 and Fe4Al13 intermetallics at Al-Fe joints. Procedia Manufacturing 15 (2018) 1407–1415 https://doi.org/10.1016/j.promfg.2018.07.341 Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)en_US
dc.relation.haspartPaper 2: Khalid M. Z., Friis J., Ninive P. H., Marthinsen K., Ringdalen I.G., Strandlie A. Modified embedded atom method potential for Fe-Al intermetallic mechanical strength: A comparative analysis of atomistic simulationsen_US
dc.relation.haspartPaper 3: Khalid, Muhammad Zeeshan; Friis, Jesper; Ninive, Per Harald; Marthinsen, Knut; Strandlie, Are. Ab-initio study of atomic structure and mechanical behaviour of Al / Fe intermetallic interfaces. Computational Materials Science 2020 ;Volum 174 https://doi.org/10.1016/j.commatsci.2019.109481 This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).en_US
dc.relation.haspartPaper 4: Khalid M. Z., Friis J., Ninive P. H., Marthinsen K., Ringdalen I.G., Strandlie A. (2019). First-principles study of tensile and shear strength of an Fe2Al5//Fe interface. The final published version is available in Computational Materials Science 2021: Volume 192, 110319 https://doi.org/10.1016/j.commatsci.2021.110319 This is an open access article under the CC BY licenseen_US
dc.relation.haspartPaper 5: Khalid, Muhammad Zeeshan; Friis, Jesper; Ninive, Per Harald; Marthinsen, Knut; Strandlie, Are. First-principles study of tensile and shear strength of Fe-Al and α-AlFeSi intermetallic compound interfaces. Computational Materials Science 2021 ;Volum 187. https://doi.org/10.1016/j.commatsci.2020.110058 This is an open access article under the CC BY licenseen_US
dc.relation.haspartPaper A: Khalid, Muhammad Zeeshan; Friis, Jesper; Ninive, Per Harald; Marthinsen, Knut; Strandlie, Are. A First-Principles Study of the Al (001)/Fe(0-11) Interface. Materials Science Forum 2018 ;Volum 941. s. 2349-2355 https://doi.org/10.4028/www.scientific.net/MSF.941.2349en_US
dc.titleAtomistic modelling of Fe-Al and α-AlFeSi intermetallic compound interfacesen_US
dc.typeDoctoral thesisen_US
dc.subject.nsiVDP::Technology: 500::Materials science and engineering: 520en_US


Tilhørende fil(er)

Thumbnail
Thumbnail

Denne innførselen finnes i følgende samling(er)

Vis enkel innførsel