QUASI-CRYSTALS IN THE TI-HF-NI SYSTEM - FORMATION CONDITIONS AND PROPERTIES

The concentration domains of quasicrystal formation in the Ti - Hf - N i system are calculated on the basis of structural diagrams. The forma tion of quasicrystals in this system is verified experimentally. The i cosahedral structure of quasicrystals in the Ti - Hf - Ni system is es tablished by X-ray diffraction. The parameters of formation of the qua sicrystalline and amorphous structures (the valence electron concentra tion and the atomic size factor) are determined. Electrical resistivit y of the icosahedral and amorphous phases in the Ti - Hf - Ni system i s higher by a factor of about 1.5 - 2 than resistivity of crystalline phases. Microhardness of the icosahedral and crystalline phases exceed s the corresponding microhardness values of amorhous phases in alloys of this system.