Micromagnetic testing of model alloys specimens: evaluating irradiation effects
This paper presents the results obtained the Model Alloy project, carried out by the JRC (Joint Research Centre) within the frame of the European Network AMES (Ageing Material Evaluation System). The objective of the project is to study the influence of elements, i.e. phosphorus, copper and nickel, on irradiation embrittlement. The samples were irradiated at 270°C in the LYRA rig at the High Flux Reactor in the Petten (NL) site of the JRC. The mechanical properties changes are followed by destructive and non-destructive tests and this paper presents the results of micromagnetic measurements, Barkhausen signal measurements, in the model alloys sub-size Chary-V specimens at fresh and irradiated conditions. The Barkhausen signal measurements, RMS values, for Mini-Charpy specimens are found to change with irradiation on the model alloys for the used setting: low applied excitation amplitude of 10 Hz sinusoidal wave. Decrease of the RMS Barkhausen noise values from 3 to 42 % are observed for the different irradiated model alloys; investigation of the influence of Cu, P and Ni are being carried out and preliminary results show that the greater sensitivity of Barkhausen signal to irradiation is found on alloys with higher nickel or copper content. This fact can be related to the nickel and copper effects on the lattice structure, strain hardening. The significant scattering of the Barkhausen measurements can be attributed to the fact that the probe was originally built up to Charpy and not Mini-Charpy specimens, so there was a considerable flux leakage affecting the pick-up signal.
Bibliographic Reference: An oral report given at: 3rd International Conference on NDE in Relation to Structural Integrity for Nuclear and Pressurised Components. Organised by: Joint Research Centre and Electric Power Research Institute (US). Held in: Seville (E
Record Number: 200214373 / Last updated on: 2002-02-15
Original language: en
Available languages: en