EFFECT OF COOLING RATE ON THE MICROSTRUCTURE OF AN Al94Mn2Be2Cu2 ALLOY

In this study the eff ect of the cooling rate on the microstructure of Al94Mn2Be2Cu2 alloy was investigated. The vacuum induction melted and cast alloy was exposed to diff erent cooling rates. The slowest cooling rate was achieved by the DSC (10 K·min−1), the moderate cooling rate succeeded by casting in the copper mould (≈1 000 K·s−1) and the rapid solidifi cation was performed by melt spinning (up to 106 K·s−1). The microstructure of the DSC-sample consisted of α-Al matrix, and several intermetallics: τ1-Al29Mn6Cu4, Al4Mn, θ-Al2Cu and Be4Al(Mn,Cu). The microstructures of the alloy at moderate and rapid cooling consisted of the α-Al matrix, i-phase and θ-Al2Cu. Particles of i-phase and θ-Al2Cu were much smaller and more uniformly distributed in melt-spun ribbons.