Development of Intermetallic Materials for Structural Applications : Toward Designing Multi-constituent and/or Multi-phase Alloys

The present paper emphasizes that only the designing of multi-constituent andlor multi-phase alloys can meet the requirements of real structural applications, by using several results of our recent work in ONERA, which aims at taking advantage of the huge potential offered by numerous combinations of metallic elements in intermetallics. The paper develops the following three points : 1) designing novel alloy systems showing a twophase y-y'-type microstructure observed in Ni-base superalloys, 2) advantage of the two-phase y++ lamellar structure and its complexity in TiAl-base alloys, 3) problems associated with the degree of order in complex B2 aluminides of refractory metals and an unusually high room-temperature tensile ductility obtained in some of them. Finally, we try to indicate the type of further contribution stemming from the work of basic research scientists, which can be useful for future activities in the development of intermetallic materials.