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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Strangwood, Martin
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (19/19 displayed)
- 2020Sports Materialscitations
- 2019Grain growth on reheating for an as-cast Al-Nb-containing steel with segregated compositioncitations
- 2019Effect of grain size distribution on recrystallisation kinetics in an Fe-30Ni model alloycitations
- 2018Characterisation of precipitation and coarsening of carbides during tempering in a low alloyed quenched and tempered steelcitations
- 2018Characterisation of precipitation and carbide coarsening in low carbon low alloy Q&T steels during the early stages of temperingcitations
- 2017Skeletonisation to Find the Centre of Dendrites Traced from a 2D Microstructural Image
- 2016Effect of grain size distribution on recrystallisation kinetics in a Fe-30Ni model alloy
- 2015Electromagnetic evaluation of the microstructure of grade 91 tubes/pipescitations
- 2014Stereologische Analyse der mikrostrukturellen Inhomogenitäten in durch Kokillenguss mit Direktkühlung und durch konventionellen Strangguss verarbeiteten Aluminium-Magnesium-Legierung (AA5754)
- 2013The effect of hydrogen on porosity formation during electron beam welding of titanium alloys
- 2013Magnetic evaluation of microstructure changes in 9Cr-1Mo and 2.25Cr-1Mo steels using electromagnetic sensorscitations
- 2012The effect of hydrogen on porosity formation during electron beam welding of titanium alloys
- 2012On the mechanism of porosity formation during welding of titanium alloyscitations
- 2012Hydrogen Transport and Rationalization of Porosity Formation during Welding of Titanium Alloyscitations
- 2012Coupled thermodynamic/kinetic model for hydrogen transport during electron beam welding of titanium alloycitations
- 2009Microstructure-property development in friction stir welds of Al-Mg alloys
- 2007Microstructure-microhardness relationships in friction stir welded AA5251citations
- 2007Influence of base metal microstructure on microstructural development in aluminium based alloy friction stir weldscitations
- 2005Microstructural development during friction stir welding of work hardenable Al-Mg alloys
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article
On the mechanism of porosity formation during welding of titanium alloys
Abstract
The mechanism of porosity formation during the fusion welding of titanium and its alloys is studied. Porosity formed during the electron beam welding of titanium is characterized using high-resolution X-ray tomography, residual gas analysis and metallographic sectioning; the results confirm that porosity formation is associated with evolution of gas, especially hydrogen. A model for hydrogen diffusion-controlled bubble growth is proposed, to aid in the interpretation of these findings. To investigate further the effect of hydrogen on porosity formation, hydrogen charging is used to achieve different hydrogen levels prior to welding. The results confirm that porosity can be suppressed even at every high hydrogen levels, when welding is carried out with optimized welding parameters and perfect joint alignment; on the other hand, porosity is exacerbated when a small beam offset is employed. This is because any beam offset alters the size of the liquid zone at the melting front, where the joint edges first become melted. It is proposed that the thickness of the liquid film at the melting front is crucial for bubble nucleation and bubble survival in the weld pool; bubbles can escape through the keyhole by breaking through this liquid film, when it is too thin. This challenges the common assumption of bubble escape by flotation to the weld pool surface. Thus the nucleation rate in the liquid zone at the melting front determines the likelihood of porosity occurring. This suggests that the beam offset is likely to be one factor influencing porosity formation in these circumstances. The paper provides fundamental insights into the mechanism of porosity formation during the welding of titanium alloys and guidance to aid in its elimination.