Microstructural evolution and microhardness of a melt-spun Al-6Ni-2Cu-1Si (in wt.%) alloy

Al-Ni-Cu-Si alloy with nominal composition of Al-6 wt.% Ni-2 wt.% Cu-1 wt.% Si alloy were rapidly solidified by the using melt spinning technique to examine the influence of the cooling rate/conditions on microstructure and mechanical properties. The microstructures of the rapidly solidified ribbons and ingot samples were investigated by the optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD analysis indicated that Ingot samples were Al, Al3Ni, Al2Cu and Si phases. The OM and SEM results show that the microstructure of rapidly solidified ribbons is clearly different from that of the chill-casting alloy and the structures of alloy melt-spun ribbons were completely composed of finely dispersed alpha-Al and intermetallic Al3Ni phase. The microhardness values of the melt-spun ribbons were about 3.2 times higher than those of Ingot counterparts. (c) 2007 Elsevier B.V. All rights reserved.