The microstructures of copper-aluminium-nickel-iron quaternary alloys, especially the cause of κ-phase precipitation, is greatly influenced by percentages of nickel and iron. And because these alloys are regarded as precipitation hardening alloys, the relationship between their type of precipitates and their mechanical properties is important. Therefore the relationship between microstructure and mechanical properties were investigated using quaternary alloys containing aluminium 9 to 10%, nickel 1 to 6% and iron 1 to 6%.
The effect of adding nickel and iron to copper-aluminium alloys is more remarkable in increasing the mechanical strength by κ-phase precipitation than in increasing the strength of the α matrix by dissolving into a solid solution. Nickel rich κ precipitates are a predominant factor for mechanical properties, and the effect of adding iron influences them by changing the type of the κ phase precipitates and the mean free path between particles.
A favorable mechanical properties were obtained when the Ni%+Fe% makes about 10% and the [Fe%]/[Ni%] ratio is about 1.1, and this is explained by the type of the κ phase precipitates and their distribution.
(Received October 15, 1960)
* This paper was read at the general meeting of Japan Institute of Metals held at Tokyo on April 1959, and was written originally in Japanese in the Journal of the Japan Institute of Metals, 24 (1960), 205.
** Laboratory of the Mitsubishi Shipbuilding and Engineering Co., Ltd.
© 2002 The Japan Institute of Metals
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