Composition and Structural Evolution of Al-Me Alloys (Me = Fe, Cu, Sb) Prepared by Means of Ultrarapid Quenching from the Melt Studied by RBS Technique

The hardness of thin ribbons and related composition in rapidly solidified Al-Sb, Al-Cu, Al-Fe alloys have been investigated by Vickers measurements and Rutherford backscattering spectroscopy. Optical microscopy was employed for microstructural analysis of alloys. Rapid solidification of Al-Cu and Al-Fe alloys leads to a substantial increase of the hardness of the Al-Fe foils. In the investigated range of the admixtures the hardness increases from 220 to 412 and 840 MPa in Al-Cu and Al-Fe alloys, respectively. The hardness of Al-Sb alloy does not increase significantly, and the dependence on dopant concentration is more complicated. A compositional study of the alloys showed a many-fold enhancement of the admixture concentration in a surface (10-20 nm) region of all the investigated Al-Me foils. (Author)