T. J. Watson

Crystallization of Glassy Powder from Aluminum-Rare Earth- Transition Metal Alloys

The microstructures exhibited by gas atomized powders of two alloys, Al-6Gd-6Ni-1Fe and Al-5Y-10Ni (at. %), have been analyzed using electron microscopy. It was found that the microstructure depends critically on the particle size obtained during atomization. Small particles ( 30μm) are often fully crystalline, consisting of fine interspersed Al and intermetallic grains.

Microstructure And Ternary Phases In Al-rich Al-Y-Ni Alloys.

The results of a transmission electron microscopy study on the crystal structures and morphologies exhibited by each of the phases in a set of four Al-rich Al-Y-Ni alloys which contain 1.7–4.5 at. % Y and 3.5–10.1 at. % Ni are presented. It is shown that each alloy contains fcc-Al, a binary Al 3 Ni or Al 3 Y phase (depending on alloy composition), and a ternary phase. The same ternary phase was found in each alloy and this was found to correspond to a new phase Al 19 Ni 5 Y 3 (Cmcm, a=0.4025 nm, b=0.799 nm and c= 2.689 nm, Al 19 Ni 5 Gd 3 structure type). In many cases, the ternary particles also contain embedded slabs of the equilibrium Al 23 Ni 6 Y 4 phase. This phase mixture did not decompose even after extended annealing.