W-2 wt.%Y2O3 composite: Microstructure and mechanical properties

Nadine Baluc, Robin Schäublin, Philippe Spätig
2012
Article

Résumé

A W-2Y(2)O(3) composite is produced by powder metallurgy, including the pressing of the mixed elemental powders, their sintering and hot forging. The microstructure of the obtained composite is investigated using light microscopy, scanning electron microscopy and transmission electron microscopy. It appears that the material is composed of W grains having a mean size of 1-2 mu m and Y2O3 particles having a mean size of 300 nm to 1 mu m. The W grains contain a high density of dislocations. The mechanical properties of this material are investigated using nanoindentation and 3-point bend test. Berkovich hardness value is found to be 4.9 GPa at 10 N load, which is similar to that of pure W. 3-Point bend test shows that the composite starts to show ductile behavior approximately at 400 degrees C and the bending stress continuously decreases from 200 degrees C to 1000 degrees C. (C) 2012 Elsevier B.V. All rights reserved.

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Nadine Baluc, Robin Schäublin, Philippe Spätig
2012
Article

Résumé

Official source

https://infoscience.epfl.ch/record/176449?ln=fr

À propos de ce résultat

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Microstructure and mechanical properties of a W-2wt.%Y2O3 composite produced by sintering and hot forging

Nadine Baluc, Robin Schäublin, Philippe Spätig

A W-2Y(2)O(3) composite has been developed by powder metallurgy methods in collaboration with the Plansee Company (Austria). The microstructure of the composite was analyzed using transmission electron microscopy and electron backscatter diffraction in scanning electron microscopy. The mechanical properties of the composite were analyzed using nano-indentation experiments, tensile and Charpy impact tests. It was mainly found that the composite exhibits ductile tensile behavior at 673-1273 K but weak Charpy impact properties, characterized by low absorbed energy values, at 773-1273 K. (C) 2013 Elsevier B.V. All rights reserved.

2013

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A W-2Y(2)O(3) material was developed in collaboration with the Plansee Company (Austria). An ingot of the material having approximate dimension of 95 mm x 20 mm was fabricated by mixing the elemental powders followed by pressing, sintering and hot forging. The microstructure of the W-2Y(2)O(3) composite was investigated using transmission electron microscopy (TEM). The microhardness wasostudied using nano-indentation technique. We observed that the W-grains having a mean size of about 1 mu m already formed and these grains contain very low density of dislocations. The size of the yttria particles was between 300 nm and 1 mu m and the Berkovich hardness was about 4.8 GPa. The specimens were irradiated/implanted with Fe and He ions at JANNuS facility located at Orsay/Saclay, France. The TEM disks kept were irradiated/implanted at 300 and 700 degrees C using Fe and He ions with an energy of 24 and 2 MeV, respectively. The calculated radiation dose was about 5 dpa produced by Fe ions and total He content is 75 appm at both 300 and 700 degrees C. From the TEM investigation of irradiated samples, few radiation loops are present on the W grains, whereas on yttria particles, the radiation induced damages appear as voids. Berkovich hardness of the irradiated sample is higher than that of the non-irradiated sample. Results on the microstructure and microhardness of the ion-irradiated W-2Y(2)O(3) composites are presented in detail. (C) 2013 Elsevier B.V. All rights reserved.

Elsevier Science Sa2013

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Investigation of microstructure and mechanical properties of W-Y and W-Y2O3 materials fabricated by powder metallurgy method

Nadine Baluc, Lyubomira Veleva

W-2Y, W-1Y(2)O(3) and W-2Y(2)O(3) materials have been fabricated using two different powder metallurgy methods. While W-2Y and W-1Y(2)O(3) have been fabricated using mechanical alloying and hot isostatic pressing (Hipping), W-2Y(2)O(3) has been fabricated by sintering and hot forging method. Transmission electron microscopy observation reveals that W-2Y and W-1Y(2)O(3) materials have nano-structured grains whereas W-2Y(2)O(3) material has pm size grains. In both cases, the particles are distributed in homogeneously inside the grains. Berkovich hardness and 3 point bend tests confirm that in-spite of nano-structured grains, W-2Y, and W-1Y(2)O(3) materials are highly stiff and show no ductility till 1000 degrees C temperature range. In the case of W-2Y(2)O(3), the Berkovich hardness value is found to be 4.9 GPa, that is similar to the Berkovich hardness value of pure Wand 3-point bend test confirms that W-2Y(2)O(3) is ductile at 400 degrees C and above. Relation between the fabrication techniques, the microstructures and mechanical properties in W-2Y, W-1Y(2)O(3) and W-2Y(2)O(3) materials is reported. (C) 2015 Elsevier Ltd. All rights reserved.

Elsevier Sci Ltd2015

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