Influence of the iron content on the solidification behaviour of cast aluminium bronze used in marine applications

Abstract

The effect of iron addition to Cu-Al-Ni alloys (in the zone of the chemical composition of commercial aluminium bronze) has been studied. The quaternary alloys were melted from a base Cu-Al-Ni alloy with iron additions up to ~6 at.%. Simultaneous Differential Thermal Analysis and Termogravimetry (DSC/TGA) and isothermal homogenisation with rapid cooling have been employed to determine the equilibrium phases at different temperatures and the existing invariant reactions. The alloys were observed by Optical Microscopy (OP) and by Scanning Electron Microscopy (SEM). The chemical analysis of the phases has been determined by Energy-Dispersive Spectroscopy (EDS). The results obtained allow the determination of the effect of the iron content in the sequence of phase formation. The chemical compositions of the phases obtained are compared with the same phases in the commercial alloys, with other alloying elements being present. The effect of iron content on the “liquidus” temperature and phase compositions of the invariant reactions detected, in the range of compositions studied, are presented.