Abstract
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.
