Instituto Balseiro UNCU

Argentina

Instituto Balseiro UNCU

Argentina
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Kempf R.A.,GCCN | Sacanell J.,CONICET | Milano J.,CONICET | Guerra Mendez N.,CONICET | And 5 more authors.
Journal of Nuclear Materials | Year: 2014

Since reactor pressure vessel steels are ferromagnetic, provide a convenient means to monitor changes in the mechanical properties of the material upon irradiation with high energy particles, by measuring their magnetic properties. Here, we discuss the correlation between mechanical and magnetic properties and microstructure, by studying the flux effect on the nuclear pressure vessel steel used in reactors currently under construction in Argentina. Charpy-V notched specimens of this steel were irradiated in the RA1 experimental reactor at 275°C with two lead factors (LFs), 93 and 183. The magnetic properties were studied by means of DC magnetometry and ferromagnetic resonance. The results show that the coercive field and magnetic anisotropy spatial distribution are sensitive to the LF and can be explained by taking into account the evolution of the microstructure with this parameter. The saturation magnetization shows a dominant dependence on the accumulated damage. Consequently, the mentioned techniques are suitable to estimate the degradation of the reactor vessel steel. © 2013 Published by Elsevier B.V.


Talaganis B.A.,Instituto Balseiro UNCu | Talaganis B.A.,CONICET | Esquivel M.R.,Instituto Balseiro UNCu | Esquivel M.R.,Bariloche Atomic Center | And 4 more authors.
Journal of Alloys and Compounds | Year: 2010

In this work, various AB5's were mechanically alloyed using a low energy mill until final or completion milling stages were reached. This process leaves micro- and nano-structured materials with highly distorted microstructures. Then, further annealing is needed to obtain an intermetallic suitable for hydrogen thermal compression process. After milling, the samples were annealed and analyzed by X-ray diffraction and Differential Scanning Calorimetry. Hydriding properties were studied using volumetric methods. After annealing at 200 °C for 24 h no changes occur in neither structural nor hydriding properties. For samples annealed at 400 °C, relaxation effects of the structure were observed. It occurs due to the release of strain produced by annealing on the microstructure. It leads to the improvements in both structural and hydriding properties. Strong recrystallization effect was present between 400 and 600 °C. At 600 °C, the main improvements were larger crystallite size, lower strain values and pressure-composition isotherms with well-defined plateaus. Despite this behavior, no evidence of crystallization was observed by Differential Scanning Calorimetry measurements from room temperature up to 500 °C. These topics, the amount of energy supplied during mechanical alloying and the correlation between the structural and sorption properties are discussed according to the governing mechanisms of recrystallization observed in each temperature range. From these results, an improved synthesis-thermal treatment method is outlined. © 2009 Elsevier B.V. All rights reserved.

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