Effects of Neutron Irradiation on the Mechanical Properties of a 5154-0 Type Aluminum Alloy

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A large number of Al 5154-0 tensile test specimens were irradiated in a core position facility of the High Flux Reactor in Petten, the Netherlands. They were withdrawn from the irradiation rig in seven batches with successively higher accumulated neutron fluences. The highest fluences achieved were 5.7 x 10 2 6 n/m 2 (E 0.1 MeV), which leads to a mean thermal-to-fast flux ratio of 0.95. Tne irradiation temperature was 360 K ′ 10 K. After each withdrawal the material's tensile properties were determined at 293 K, 323 K and 373 K with a calculated strain rate e 1.65 x 10 - 4 /s. At the higher fluences the ductility figures appear to drop with increasing test temperature. Irradiation to a fluence level of 6 x 10 2 6 n/m 2 causes the 0.2% flow stress to increase from ∼ 100 MPa to ∼ 520 MPa and the uniform elongation to drop from more than 20% to less than 1% at the 323 K test temperature. The results of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and light microscopy (LM) confirm that the behaviour of A1 5154-0 conforms to the general model for Al-Mg solid solution alloys obtained from the ORNL experiences with A1 5052-0. The objective of the irradiation program was to monitor the state of embrittlement that was expected to develop in the HFR core box material. The experimental results are representative for the PSF wall of the core box only. Because of the much higher thermal-to-fast neutron flux ratios prevailing in the other three walls, the test data are not directly applicable to these walls. By working out the implications of the basic model, however, it can be shown qualitatively that the ductility in the other walls will not be significantly better than in the PSF wall.