Project Details

Metastable β-Ti alloys containing Zr can be substantially strengthened by interstitial oxygen content higher than 0.4 wt% without embrittlement. Oxygen is pinning the dislocations and increased stress is needed for their movement. Metastable β alloys with optimized composition can undergo stress-induced martensitic transformation to α“ phase, which can lead to ductility enhancement (TRIP effect). Simultaneously, ductility can be improved by twinning (TWIP effect). The aim of the project is to design β-Ti alloy which will be strengthened via high oxygen content (0.5 – 1 wt%) and simultaneously its β-stabilization will be optimized so that TRIP / TWIP effect is active at higher stress than in current Ti alloys exhibiting TRIP / TWIP effect (max. 600 MPa). In the studied Ti-Nb-Zr-O system, Nb and O content will be optimized first, to achieve TRIP / TWIP effect. Zr content will be optimized subsequently to get optimal strength-ductility balance via Zr-O interaction. A complementary part of the project is devoted to partial replacement of Nb by cheaper iron for improvement of final price of the alloy. The alloys will be first prepared by FAST method to explore variety of different compositions. Selected alloys will be cast by arc-melting and thoroughly studied. Active deformation mechanisms will be studied in a single-crystal of a selected alloy. The resulting alloy with high toughness could find its use in medicine (implant production) and automotive (deformation safety zones).