Some of the fundamental problems concerning metallography encountered when copper-aluminium alloy systems are used for large casting such as marine propellers have been investigated. The microstructural analysis for ``slow cooling brittleness or self-annealing'' is obtained in copper-aluminium-nickel-iron quaternary alloys. In this paper the shift of the (α/α+δ) solubility limit curve, the coagulation of nickel and iron rich compound phase and the composition of κ phase in the alloys are discussed.
It is, also, shown that, in copper-aluminium-nickel-iron quaternary cast alloys, no precipitation of the eutectoid is observed even with an aluminium content of more than 9.4%, and stabilization is obtained at the (α+κ) phase with uniformly and finely dispersed precipitates.
(Received October 15, 1960)
* This paper was read at the general meeting of Japan Institute of Metals at Tokyo on April 1959, and was written originaly in Japanese in the Journal of the Japan Institute of Metals 24 (1960), 201.
** Laboratory of the Mitsubishi Shipbuilding and Engineering Co., Ltd.
© 2002 The Japan Institute of Metals
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