Effect of the High-Pressure Torsion (HPT) and Subsequent Isothermal Annealing on the Phase Transformation in Biomedical Ti15Mo Alloy

Metals

卷:9

Petr Doležal¹  Miloš Janeček²  Kristína Bartha²  Josef Stráský²  Anna Veverková²  Pere Barriobero-Vila³  Irina Semenova⁴  Veronika Polyakova⁴  František Lukáč⁵  Petr Sedlák⁶ 

[1] Department of Physics of Condensed Matter, Charles University, 12000 Prague, Czech Republic;

[2] Department of Physics of Materials, Charles University, 12000 Prague, Czech Republic;

[3] Institute of Materials Research, German Aerospace Center (DLR), 51147 Cologne, Germany;

[4] Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 450000 Ufa, Russia;

[5] Institute of Plasma Physics, Czech Academy of Sciences, 18000 Prague, Czech Republic;

[6] Institute of Thermomechanics, Czech Academy of Sciences, 18000 Prague, Czech Republic;

关键词: β titanium alloys;    severe plastic deformation;    α phase precipitation;    phase composition;    high energy synchrotron x-ray diffraction;   

DOI  :  10.3390/met9111194

来源: DOAJ

【 摘 要 】

Ti15Mo metastable beta Ti alloy was solution treated and subsequently deformed by high-pressure torsion (HPT). HPT-deformed and benchmark non-deformed solution-treated materials were annealed at 400 °C and 500 °C in order to investigate the effect of UFG microstructure on the α-phase precipitation. Phase evolution was examined using laboratory X-ray diffraction (XRD) and by high-energy synchrotron X-ray diffraction (HEXRD), which provided more accurate measurements. Microstructure was observed by scanning electron microscopy (SEM) and microhardness was measured for all conditions. HPT deformation was found to significantly enhance the α phase precipitation due the introduction of lattice defects such as dislocations or grain boundaries, which act as preferential nucleation sites. Moreover, in HPT-deformed material, α precipitates are small and equiaxed, contrary to the α lamellae in the non-deformed material. ω phase formation is suppressed due to massive α precipitation and consequent element partitioning. Despite that, HPT-deformed material after ageing exhibits the high microhardness exceeding 450 HV.

【 授权许可】

Unknown