Microstructure of as-cast aluminium bronze containing iron

Abstract

The morphology, crystallography, and chemistry of phases present in an as-cast commercial aluminium bronze containing iron, of nominal composition (wt-%) Cu–10Al–2·5Fe (BS 1400: AB1), and the development of microstructure on cooling from elevated temperatures, have been studied using optical and electron microscopic techniques. The as-cast microstructure consists of α-phase, martensite, and iron-rich intermetallic precipitates. The α-phase is fcc copper-rich solid solution and exhibits a Widmanstätten morphology. The martensitic phase, which is derived from the high-temperature β-phase, has the 9R crystal structure. The intermetallic particles are based on Fe₃Al and have the Do₃ structure. These iron-rich particles are precipitated in the β-phase and cause a refinement of the microstructure by providing sites for the nucleation of the β-phase, to some extent, by impeding the growth of the α-phase.

MST/150