Microstructure of Al-Mn-Be melt-spun ribbons

Microstructures of two alloys with the nominal compositions of Al92Mn3Be5 and Al89Mn6Be5 were characterized in the initial as-cast condition (after vacuum induction melting and casting) and after melt spinning. In the initial conditions, both alloys consisted of an aluminum-rich solid solution and two metastable intermetallic phases: Be4AlMn and Al10Mn3(Be). Both alloys melted over a rather large temperature range (between 230 degrees C and 310 degrees C). This was the main reason for the presence of unmelted particles in the melt-spun ribbons. Nonetheless, with the use of optimized melt-spinning parameters a microstructure composed of the Al-rich solid solution and finely dispersed quasicrystalline particles in ribbons with thicknesses ranging from 30-200 mu m was achieved. The dispersion of quasicrystalline particles was finest on the wheel side of the thinnest ribbons, attaining microhardness values between 250 HV and 300 HV. (C) 2007 Elsevier Inc. All rights reserved.