Neutron Stress Measurement of Coarse Crystal Grain in Aluminum Casting Alloy

Abstract:

Internal stresses in aluminum casting alloy were measured by the neutron stress measurement method with the apparatus RESA in Japan Atomic Energy Agency (JAEA). In usual cases, coarse crystal grains are included in aluminum casting alloy. These coarse crystal grains make it extremely difficult to estimate the internal stresses by the neutron diffraction [1]. The two problems arise because of the existence of the coarse crystal grains. The first problem is the production of an unstable diffraction profile in the necessary direction. The second is the edge effect which is generated by the overhang of the coarse crystal grains from the neutron irradiation area (gage volume). In this study, two kinds of new techniques used were proposed to resolve these problems. Firstly, the elastic theory based on the sin2ψ method is shown. Diffraction peaks in several directions were found by use of the rocking curve method. Following that, the lattice spaces in each principal direction were calculated from these diffraction peaks using the elastic theory. Secondly, the distribution of edge effect around the gage volume was measured using a small bit of copper single crystal. From this result, the edge effect was canceled out by the modified measurement method which was done symmetrically. Finally, the aluminum casting sample which included coarse crystal grains was set to the tensile testing machine on RESA’s measurement table and the applicability of these new techniques were confirmed experimentally.

• Periodical: Materials Science Forum (Volume 652)
• Pages: 243-248
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.652.243
• Online since: May 2010
• Authors: Nishida Masayuki, Hanabusa Takao, Tatsuya Matsue, Hiroshi Suzuki
• Keywords: Aluminium Casting Alloy, Coarse Crystal Grain, Neutron, Residual Stress

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