Hardness evaluation of Al-12Si-0.5Sb melt-spun ribbons

Continuous uniform ribbons of Al-12 wt.%Si-0.5 wt.%Sb were prepared by the melt spinning technique. Microhardness measurements with different loads (0.098, 0.245, 0.49, 0.98, 1.47, and 1.96 N) and a loading time of 10 s were carried out by the standard Vickers hardness testing method. The hardness was found to be load dependent. So, there was a critical load after which the calculated hardness values decreased abruptly. The values obtained by applying higher loads after the critical point did not characterize the rapidly solidified alloys. This critical load was 0.49 N for our melt-spun ribbons having about 60 mum thickness. The hardness measurements together with the cross-section morphology examination of ribbons indicate that the average hardness value calculated from different applied loads, up to critical point, leads to more realistic results than the value obtained from one applied load. (C) 2003 Elsevier B.V. All rights reserved