Abstract
Three rapidly solidified aluminium alloys containing additions of Cr, Zr, and Fe have been investigated. All three were produced by an updraught inert gas atomisation technique. A detailed electron microscopy study was performed on the: as-atomised powder particles. In the Al–5Cr–2Zr, three different types of microstructure were observed: partitionless (P), cellular (C), and a coarser type of microstructure composed of a uniform distribution of nodules within the as-atomised powder particles (termed D). The highest-Cr alloy, Al–6·43Cr–1·67Zr, exhibited two different microstructures, one similar to type D and a coarser one composed of aggregates of individual intermetallic particles. The Al–4Cr–1 Fe alloy usually exhibited a mixed microstructure composed of featureless and cellular morphologies (types P and C). The characteristic features of the Powder: microstructure may be explained in terms of solidification mechanisms, adiabatic and Isothermal regimes, and by considering the stability of the fast-moving solidification front. X-ray analysis revealed that in all three atomised powders the equilibrium Al13Cr2 phase was present in addition to the aluminium matrix. A number of unidentified reflections were attributed to a Cr-rich metàstable phase.
MST/1091
Get full access to this article
View all access options for this article.