MICROSTRUCTURES OF UNIDIRECTIONALLY SOLIDIFIED TERNARY EUTECTIC COMPOSITES CONSISTING OF Al-CuAl2 LAMELLAR EUTECTICS AND FIBROUS EUTECTICS.

Ternary eutectic alloys, Al-CuAl//2-NiCu//3Al//6, Al-CuAl//2FeCu//2Al//7 and Al-CuAl//2-Si, consisting of Al-CuAl//2 lamellar eutectics and Al-Al//3Ni, Al-Al//3Fe or Al-Si fibrous eutectics, were solidified unidirectionally over a wide range of rates. These microstructures are compared with those of concomitant binary eutectics and are discussed with reference to the term of entropy of fusion of each phase. In Al-CuAl//2-Si ternary eutectics, Si grows with prefered 100 direction fiber texture as in Al-Si binary eutectics, although Al-CuAl//2 lamellar are degenerated thoroughly.