J. Phys. IV France
Volume 05, Numéro C7, Novembre 1995
Second International Conference on Ultra High Purity Base Metals
UHPM - 95
Page(s) C7-123 - C7-128
Second International Conference on Ultra High Purity Base Metals
UHPM - 95

J. Phys. IV France 05 (1995) C7-123-C7-128

DOI: 10.1051/jp4:1995710

High Temperature Intermetallic Compounds Ni3Al

M. Kursa, L. Hypeská, J Drápala,, T Kárník and M. Losertová

VSB, Technical University Ostrava, av. 17. listopadu, 708 33 Ostrava-Poruba, Czech Republic

The paper describes the preparation of Ni3Al intermetallic compounds, and investigations of their structures in the as-cast, remelted, and annealed states. The materials were produced by three techniques : in a high frequency vacuum furnace, by zonal remelting in an electron beam furnace, and by remelting with unidirectional solidification. Those melted in an h. f. vacuum furnace and poured into graphite moulds had well developed dendritic structures, a Ni3Al (γ) phase, with interdendritic spaces formed by Ni5Al3 + [γ']. Many specimens contained shrinkage cavities. Unidirectional solidification allowed casting defects to be eliminated and the grain size to be controlled in dependence on the solidification rate. Rates from 650 to 60 mm per hour were tried to examine their effects on the grain size, homogeneity, and structure. The authors further investigated the influence of B and Zr additions on the solidification process and formation of the structure of Ni3Al. Annealing, in an argon atmosphere at 1100°C for various durations, was tried out for homogenizing the as-cast structures.

© EDP Sciences 1995