Melt-Spinning a Commercial Aluminium Alloy
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MELT-SPINNING A COMMERCIAL ALUMINIUM ALLOY
T C WILLIS, B CANTOR Department of Metallurgy and Science of Materials, University of Oxford, Parks Road, Oxford OXl 3PH,
England
ABSTRACT A commercial aluminium alloy (3004) has been melt-spun on both an aluminium and a copper substrate. The meltspinning conditions have been varied in order to determine the optimum spinning parameteis for the apparatus used. The resulting ribbon has been examined by optical microscopy, transmission electron microscopy and anodization to show differences in grain structure and second phase distribution between the as-received rolled sheet and the melt-spun ribbon. X-ray diffractometry has been used to obtain information about the different intermetallic phases present in the sheet and ribbon, and peak heights of X-ray diffractometer traces have also been used to indicate textures present in the ribbons spun on aluminium and copper substrates.
INTRODUCTION This paper reports three sets of results concerning the production of aluminium alloy sheet by a melt-spinning process. The results reported are: (1) the conditions under which melt-spun ribbons can be formed, (2) optical microscope, transmission electron microscope (TEM) and anodization evidence of the grain size and second phase distribution in the melt-spun ribbons, (3) texture and second phase data obtained from X-ray diffractometry. EXPERIMENTAL The aluminium alloy used in this investigation was Al-3004 which contains %l%Mg, '1.2%Mn, and residual quantities of Si and Fe, and was supplied in the form of rolled sheet by Metal Box PLC. Melt-spinning was carried out with 1mm diameter circular cross-section quartz nozzles, using argon or nitrogen gas to eject the induction melted alloy onto a rotating substrate of either copper or aluminium. The whole apparatus, other than the pressurized quartz nozzle, was at atmospheric pressure and in air. The nozzle to wheel gap was 1mm and the nozzle was inclined at 100 from the vertical away from the direction of the spinning wheel. Wheel speeds of between 3 and 45ms-' and ejection pressures of between 1 and 15psi were employed, and the resulting ribbons were 3 to 6mm wide and 60 to 100pm thick. Specimens for optical microscopy were mounted in thermosetting resin, ground and polished to a lpm finish, etched in Keller's reagent, and then examined in an Olympus BHM optical microscope. Specimens for TEM were jetelectropolished in 20% perchloric acid in methanol and examined in a JEOL 100C transmission electron microscope. Anodization was carried out in 2%HF, 49% ethanol, and 49% H2 0, at 25V [1]. X-ray analysis was carried out using CuKc radiation, with the ribbon mounted on a glass slide in a Philips PW 1130 X-ray diffractometer. Scan rat• of ; and 20 per minute were used for texture analysis and phase identification respectively.
Mat.
Res.
Soc.
Symp.
Proc. Vol.
28 (1984)(Elsevier Science Publishing Co.,
Inc.
132
RESULTS AND DISCUSSION Ribbon Production Fig.l shows a graph of wheel speed versus gas ejection pressure, with data points whi
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