EXAFS and SAXS analysis for nano-structural origin of high strength for supersaturated Al100-xFex (x=1, 2.5) alloys

Local structures around Fe atoms and nano-size structures in high strength supersaturated Al100-xFex (x = 1.0 and 2.5) alloys prepared by the electron-beam deposition on a low temperature (373 K) substrate (LTS) and a high temperature (523 K) substrate (HTS) are studied by means of extended X-ray absorption fine structure (EXAFS) and small angle X-ray scattering (SAXS). In the Al99.0Fe1.0 (LTS) alloy, EXAFS result shows that Fe atoms substitute fcc-Al, and cause lattice distortion at least of 5.7 Angstrom from iron atoms. On the other hand, Al2Fe and/or Al3Fe intermetallic compounds precipitate in the Al99.0Fe1.0 (HTS) and the Al97.5Fe2.5 (HTS) samples. SXAS results show that the size and the inter-particle distance of precipitates is approximately 20 and 80 Angstrom, respectively. Fe atoms in the Al97.5Fe2.5 (LTS) are included both in the solid solution of Al-Fe and a Al2Fe and/or a Al3Fe intermetallic compounds with the size of 8 Angstrom and the inter-particle distance of 49 A. (C) 2003 Elsevier B.V. All rights reserved.