| People | Locations | Statistics |
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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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Karhu, Marjaana
VTT Technical Research Centre of Finland
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (27/27 displayed)
- 2023Investigation of Novel Nano-carbide WC/CoCr Coatings Applied by HVAFcitations
- 2022Investigation of novel nano-carbide WC/CoCr coatings applied by HVAF
- 2022Mining tailings as a raw material for glass-bonded thermally sprayed ceramic coatings : Microstructure and propertiescitations
- 2020Utilizing mixed-mineralogy ferroan magnesite tailings as the source of magnesium oxide in magnesium potassium phosphate cementcitations
- 2020Utilizing mixed-mineralogy ferroan magnesite tailings as the source of magnesium oxide in magnesium potassium phosphate cementcitations
- 2020Utilization of Mineral Side Streams in High Temperature Ceramic Materials:Dissertation
- 2020Mining tailings as a raw material for glass-bonded thermally sprayed ceramic coatings:Microstructure and propertiescitations
- 2019Magnesite-rich mining tailings as a raw material for refractory ceramics:Microstructural and thermal analysiscitations
- 2019Mining tailings as raw materials for reaction-sintered aluminosilicate ceramics : Effect of mineralogical composition on microstructure and propertiescitations
- 2019Mining tailings as raw materials for reaction-sintered aluminosilicate ceramicscitations
- 2019Mining tailings as raw materials for reaction-sintered aluminosilicate ceramics:Effect of mineralogical composition on microstructure and propertiescitations
- 2018Nanocrystalline WC-Co HVAF Coatings by Utilizing Novel Powder Manufacturing Route Using Water-Soluble Raw Materialscitations
- 2017Reaction heat utilization in aluminosilicate-based ceramics synthesis and sintering
- 2017Nanostructural WC-Co coatings by utilizing novel powder manufacturing route using water soluble raw materials
- 2016Preparing nano structural WC-Co powders by utilizing soluble raw materials by spray drying and synthesis method
- 2016Preparing nano-structural WC-Co coatings by utilizing novel powder manufacturing route
- 2016Synthesis of nano structural Cr 3 C 2 powders from water soluble precursors
- 2016Reaction heat utilization potential in mullite and spinel based ceramics synthesis and sintering
- 2016Exothermic assisted synthesis of mullite and spinel based ceramics
- 2016Reaction heat potential utilization in mullite and spinel based ceramics synthesis and sintering
- 2016Synthesis of nano structural Cr3C2 powders from water soluble precursors
- 2015Synthesis of nano structural WC-Co powders from water soluble precursors: effects of carbon content to chemical and phase structure
- 2015Synthesis of nano structural WC-Co powders from water soluble precursors:Effects of tungsten source and synthesis atmosphere on chemical and phase structure evolutions
- 2015Sintering of nano structural WC with cobalt matrix synthesised from soluble raw materials
- 2015Novel titanium carbide based hard metal alternative for traditional WC-Co
- 2012Microstructure analysis and damage patterns of thermally cycled Ti-49.7Ni (at.%) wirescitations
- 2011R-phase actuated SMA composites in adaptive wind turbine blade trailing edge
Places of action
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article
Microstructure analysis and damage patterns of thermally cycled Ti-49.7Ni (at.%) wires
Abstract
Long-term behaviour and fatigue endurance are the key issues in the utilization of SMA actuators, but systematic research work is still needed in this field. This study concentrates on the effects of three major design parameters on the long-term behaviour of binary Ti49.7Ni-based actuators: the effect of the temperature interval used on thermal cycling, the effect of the stress level used and the effect of the heat-treatment state of the wire used. The long-term behaviour of the wires was studied in a custom-built fatigue test frame in which the wires were thermally cycled under a constant stress level. Before the fatigue testing, a series of heat treatments was carried out to generate optimal actuator properties for the wires. This paper concentrates on the systematic fractographic analysis of the fatigue fractured Ti49.7Ni wires. The aim was to discover the relationships between the macro-scale behaviour and the microstructural changes of the material. During thermal cycling the surfaces of the Ti49.7Ni wires were examined with an optical microscope. Clear connections between the detected surface defects and fracture nucleation sites were not established. Multiple cracks were initiated and grew during thermal cycling. SEM examinations showed that the fracture surfaces can be divided into different and separate zones: a smooth surface region with radial marks indicating the fatigue crack propagation area, a rougher ductile fracture surface region area and the roughest surface region on the interface of these two surfaces. It was detected that the size of the crack propagation area is related to the fatigue lives of the thermally cycled wires. Surface cracking and subsequent crack growth proved to be responsible for the accumulation of fatigue damage in the studied wires. It was detected from the fracture surface cross-sections that cracks were not initiated at the oxide layer. The major factor for nucleating the surface cracking and then shortening the fatigue endurance of the binary SMA actuator wires seems ...