一方向凝固によるAl-Si-Al₃Ni 3元共晶繊維複合合金の組織について

抄録

In recent years increasing attension has been given to the production of eutectic fibrous composites produced by the unidirectional solidification technique. For binary alloys, many kinds of eutectic composites have been reported, but very little has been known about ternary eutectics. In this paper, the preparation of an Al-Si-Al₃Ni ternary eutectic fibrous composite has been investigated by means of unidirectional solidification. And growth mechanism of the ternary eutectic composite was discussed.
The main results are as follows: (1) In the controlled microstructure of Al-Si-Al₃Ni eutectics, platelet silicon and Al₃Ni rods were aligned each other in a growth direction in the aluminum matrix. (2) Increasing the rate of solidification caused the interesting change of microstructure and altered the type of growth profile of the silicon colony. (3) The growth mechanism of the silicon phase in the aluminum matrix was remarkably modified by the addition of nickel atoms, so the microstructure of Al-Si-Al₃Ni eutectic alloy can more easily be controlled than that of Al-Si eutectic alloys.
From this investigation it has been concluded that some serious shortcomings of the eutectic approach to reinforced composites may be greatly improved by the addition of third or more elements.