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Ti-15Mo alloy belongs to metastable β-Ti alloys that are currently used in aircraft manufacturing and Ti15Mo alloy is a perspective candidate for the use in medicine thanks to its biotolerant composition. In this study, Ti15Mo alloy was prepared by advanced techniques of powder metallurgy. The powder of gas atomized Ti-15Mo alloy was subjected to cryogenic milling to achieve ultra-fine grained microstructure within the powder particles. Powder was subsequently compacted using spark plasma sintering (SPS). The effect of cryogenic milling on the microstructure and phase composition of final bulk material after SPS was studied by scanning electron microscopy. Sintering at 750°C was not sufficient for achieving full density in gas atomized powder, while milled material could be successfully sintered at this temperature. Alpha phase particles precipitated during sintering and their size, as well as the size of beta matrix grains, was strongly affected by the sintering temperature.

In this study, Ti-15Mo alloy powder was prepared by gas atomization and subsequent cryogenic milling in order to achieve ultra-fine grained microstructure. Both milled and non-milled powders were compacted by spark plasma sintering (SPS) at temperature of 800 °C for different sintering times up to 6 minutes. Sintering temperature and time affect porosity, microstructure and phase composition of the alloy. Milled powder can be sintered at comparatively lower temperature to achieve fully dense material. Sintering below β-transus temperature results in α+β-structure. Furthermore, amount of α-phase is higher in the material sintered from the milled powder due to increased oxygen content and also due to refined microstructure which facilitates α-phase precipitation. Mechanical properties are also affected by formation of ω-phase during uncontrolled cooling in the SPS machine.

In the bachelor thesis, mechanical properties and microstructure of Ti-15Mo alloy prepared by equal channel angular pressing were studied along with their dependence on the number of passes. Microhardness was studied by Vickers method, microstructure was studied by scanning electron microscopy and by electron back-scattered diffraction (EBSD). Finally, the elasticity modulus was measured by resonant ultra-sound spectroscopy. Mircohardness significantly increased after the first ECAP pass. After the second and the third pass it was almost constant and it again distinctly rose after the fourth pass. Grains with the size of hundreds of micrometres were observed in all samples. The volume fraction of twinned material increased with the number of passes. Deformation bands were also observed, namely in samples after two and three passes. Elastic modulus significantly increased with increasing deformation by ECAP and the evolution of elastic modulus is qualitatively similar to the evolution of microhardness. Considering that the material was processed by ECAP at 250řC, the omega phase may have formed during the processing. The increase of microhardness and elastic modulus can be explained by the increasing volume fraction of the omega phase.

Metastable β-titanium alloys are perspective candidates for use in biomedicine. For that purpose a high strength of these materials is required. The enhanced strength of these alloys can be achieved by subjecting the material to severe plastic deformation. However, due to the limited ductility of the metastable β-titanium alloys, deformation of the alloy in β solution treated condition at room temperature is sometimes inaccessible. In this study a Ti15Mo alloy in a two phase α+β condition was subjected to equal channel angular pressing at elevated temperature of 400°C. The resulting microstructure after N = 4 and 8 ECAP passes consists of deformed β-phase with elongated α-phase particles. Despite the microstructure is not ultra-fine grained the microhardness of the deformed alloy exhibits higher values compared to the non-deformed counterpart.