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Descripción
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| Tungsten materials and alloys are considered as candidate materials for next generation nuclear fusion reactors. Unfortunately, its use for structural applications is compromised due to its inherent brittleness. In order to improve this crucial feature, it is necessary to accurately measure its fracture toughness, independent of geometrical parameters and the method used to introduce the induced crack. This is the objective of this work, where the notch tip radius influence on the fracture toughness of a brittle nanostructured tungsten alloy is analysed in depth. Three point bending tests (TPB) were performed at room temperature on four types of notch geometries in which the notch root radius was gradually reduced. Notches were introduced via four different methods: classical diamond disk, diamond wire, razor blade and ultra-short pulsed laser. Single edge notched beam (SENB) specimens overestimate fracture toughness values and introduce some deformation on the notch root grains. Razor blade (SEVNB), however, gives very good results with low dispersion, but is only suitable for coarse grain materials since size effect appears when the grain size decreases. In a case of nanostructured materials as in this case, notch root radius is still too big (several times the grain size), requiring a new method to be implemented. This was solved by producing very sharp single edge laser-notched beam (SELNB) specimens, 5-20 nm root radius, by ultra-short pulsed laser ablation. This method was previously used on ceramics but no evidence of its use was found on metals. | |
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Internacional
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Si |
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Nombre congreso
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EUROMAT 2015, European Congress and Exhibition on Advanced Materials and Processes |
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Tipo de participación
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960 |
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Lugar del congreso
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Warsaw, Poland |
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Revisores
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Si |
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ISBN o ISSN
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0000-0000 |
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DOI
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Fecha inicio congreso
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20/09/2015 |
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Fecha fin congreso
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24/09/2015 |
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Desde la página
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1 |
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Hasta la página
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1111 |
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Título de las actas
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Influence of the notch root radius on the fracture toughness of brittle metals: nanostructure tungsten alloy, a case study |