Microestructuras de solidifacion y sus caracteristicas en lingotes-cuña en el sistema aluminio-niquel

The effects of solidification conditions on microstructure in wedge chill casting of ingots with the Al-Ni system. Three Al-Ni alloys, Al-6.1, 9.2 y 17.1 wt%Ni were prepared and cast into a wedge-shape mold at 100°C above the liquids temperature. These ingots were analyzed longitudinally by optical and scanning electron microscopy and by X-ray diffraction. Three main types of microstructure A1= (αA+Al-Al₃N), E1=(Al-Al₃Ni) and B1=(Al₃Ni+Al-Al₃Ni) were observed, which presented two transitions in the eutectic: from B1 →E1 en Al-9.2% Ni and from E1 →Al en Al-6.1%Ni, with increase of the growth velocity. The primary phase Al₃Ni in B1 was formed at higher alloy contents, while the primary phase αA1 in A1 was only observed in Al-6 wt% Ni.