LAUSR

We study new biomedical alloys of the Ti–18Nb– x Si system with 0.6–1.2 wt.% Si both in the as-cast state and quenched in water after holding at temperatures from 800 to 1200°С. It is shown that their solid-solution hardening within certain temperature ranges is supplemented by dispersion hardening with silicides. Rapid cooling after melting promotes the formation of nonequilibrium partially quenched structures with dispersed secondary silicides and high hardness. Quenching at lower temperatures (800–1000°С) leads to an increase in the number and sizes of silicide precipitates and to the depletion of the solid solution of silicon as a result of which the level of hardness decreases. For high quenching temperatures (> 1100°С), the silicides are practically dissolved and the level of hardness also decreases. The temperature range 1050–1150°С proves to be optimal for the purposes of quenching of biocompatible alloys of the Ti–18Nb– x Si system.