Microstructure of a eutectic NiAl—Mo alloy directionally solidified using an industrial scale and a laboratory scale Bridgman furnace

Abstract The eutectic NiAl-9Mo (at.%) alloy was directionally solidified using an industrial scale Bridgman furnace and using a liquid metal cooling Bridgman furnace to produce in-situ composites of aligned Mo fibers in an NiAl matrix. In the first part of the experiment, an investment casting shell mold system, produced for NiAl alloys, was used and investigated for the NiAl-9Mo alloy in the industrial scale furnace. Due to the lower temperature gradient of ∼2.8 K mm−1, the microstructure of the samples was dendritic. In the second part of the experiment, samples with well aligned Mo fibers were produced in the laboratory Bridgman furnace using a temperature gradient of ∼11 K mm−1 and growth rates of 0.33–0.66 mm min−1.