ACNS Logo

College Park, Maryland      June 6 - 10 , 2004

WP56: An analysis of copper precipitation in the thermally aged FeCu alloy using micro magnetic technique and SANS

D.G. Park (Korea Atomic Energy Research Institute, Yuseong P.O. Box 105, Daejeon, 305-600, Korea), M.N. Lee (Pohang University of Science and Technology, Materials Science and Engineering, Hyoja-Dong, Nam-Gu, Pohang, Kyungsangbuk-Do, 790-784, Korea), J.H. Kim, S.C. Kwon (Korea Atomic Energy Research Institute, Yuseong P.O. Box 105, Daejeon, 305-600, Korea), Y.M. Koo (Pohang University of Science and Technology, Materials Science and Engineering, Hyoja-Dong, Nam-Gu, Pohang, Kyungsangbuk-Do, 790-784, Korea), J.H. Hong (Korea Atomic Energy Research Institute, Yuseong P.O. Box 105, Daejeon, 305-600, Korea)

In order to study the effect of the copper precipitate in the steel embrittlement under neutron irradiation, the characteristic of nano size defects were investigated in the thermal aged FeCu model alloys. The copper precipitation leads to a distortion of the crystal lattice surrounding the copper precipitates and yields internal micro-stress [1]. To verify the role of copper precipitation, microhardness test, stress related magnetic Barkhausen noise measurements and small angle neutron scattering (SANS) under magnetic field experiments were carried out. The results on precipitation composition, number density, size distribution and matrix composition obtained using high resolution TEM and SANS are compared and contrasted. The diameter of copper precipitates given by SANS varied from 3~10 nm, and increased continuously with aging time. For the thermally aged alloy, the most notable results include the clear observation of copper-rich precipitates, evidence for the retention of a significant copper fraction in solid solution at the peak of hardening, for a bimodal distribution of particle sizes in the averaged condition.

[1] I. Altpeter et al., Nucl. Eng. Design, 206 (2001) 337-350

Back to the Program



Last modified 18-May-2004 by website owner: NCNR (attn: Bill Kamitakahara)