Observation of microstructure and corrosion behaviour of some aluminium bronzes

Abstract

The short term corrosion behaviour of four as-cast commercial aluminium bronzes has been examined by immersing the materials in artificial sea water for various lengths of time. Optical and scanning electron microscopy showed that the phases which underwent selective attack were: martensitiβ in the aluminium bronze, ABI; martensitic β and lamellar eutectoidal fcc α phase in nickel aluminium bronze; the cph y phase present both as a lamellar and matrix constituent in silicon aluminium bronze; and the ordered β phase and the fcc dendritic phase, rich in iron and manganese, in copper manganese aluminium bronze. The rates of corrosion of these phases were influenced by their volume fractions, morphologies, and distributions in the alloys.