CHARACTERIZATION OF A SOLID-SOLUTION OF CU IN AL-CU-SICP METAL-MATRIXCOMPOSITES PROCESSED BY SPRAY ATOMIZATION AND CODEPOSITION

The effect of silicon carbide particulate (SiCp) reinforcement on the formation of a solid solution of copper (Cu) in Al-Cu alloys during sp ray atomization and co-deposition is investigated. The extent of Cu so lid solubility in sample compositions of Al-1.3, 5.9 and 18.3 wt% Cu a nd Al-1.5, 5.9 and 19.4 wt% Cu+6 vol% SiCp was characterized using X-r ay diffraction scanning electron microscopy, (SEM) microanalysis and h igh resolution electron microscope techniques. The copper content reta ined in the alpha-Al solid solution in Al-alloys both with and without SiCp additions was determined by initially deriving the lattice param eter (a) values of the samples by X-ray diffraction and the copper con tent in the solid solution was determined using a plot of a versus cop per content previously, reported in the literature. Results of SEM mic roanalyses performed on the above alloys in regions of alpha-Al solid solution showed a good agreement on the amount of Cu retained in solid solution with values determined by X-ray diffraction especially for a lloys containing small amounts of Cu. High resolution electron microsc opy images of the matrix and the matrix/SiCp interface were employed i n order to determine values of the interplanar spacing (d) for the alp ha-Al solid solution and to correlate these values using the plot of l attice parameter as a function of copper content retained in solid sol ution. The results were in good agreement with those determined by the scanning electron microscopy microanalyses.