Ti-Mo Alloys Research Articles

Microstructure and microhardness of the Ti15Mo alloy subjected to severe plastic deformation in α+β condition

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.

Atomic-scale investigation of hydrogen distribution in a Ti[sbnd]Mo alloy

Ingress of hydrogen is often linked to catastrophic failure of Ti-alloys. Here, we quantify the hydrogen distribution in fully β and α + β TiMo alloys by using atom probe tomography. Hydrogen does not segregate at grain boundaries in the fully β sample but segregates at some α/β phase boundaries with a composition exceeding 20 at.% in the α + β sample. No stable hydrides were observed in either sample. The hydrogen concentration in β phases linearly decreases from ~13 at. % to ~4 at. % with increasing Mo-content, which is ascribed to the suppression of hydrogen uptake by Mo addition.

Novel insight into the formation of α″-martensite and ω-phase with cluster structure in metastable Ti-Mo alloys

On the basis of the “-Mo-Ti-Mo-” linear unit along the specific <111>β, <110>β, and <100>β directions, the cluster structures of α″-martensite and ω-phase were constructed in metastable Ti-Mo alloys to examine phase stability, elastic property, and crystal structure evolution by first-principles calculations combined with experimental analyses. With the increase in Mo content, the orthorhombicity and shuffle magnitude of {110}β plane along <110>β direction decreased, leading to change in the crystal structure of martensite from hexagonal close-packed to orthorhombic structure; the displacive collapse degree of {112}β plane along <111>β direction decreased, indicating that the crystal structure of ω-phase transited from hexagonal to trigonal structure. The softening effect of tetragonal shear elastic constant (C′) and Young's modulus (E100) was favorable for the shuffle and shear components of α″-martensite, respectively, whereas that of shear modulus (G111) was beneficial to the collapse component of ω-phase. The competition among C′, E100, and G111 affected the phase transformation following the sequence of hexagonal close-packed α′-martensite, orthorhombic α″-martensite, hexagonal ω-phase, and trigonal ω-phase in metastable titanium alloys.

PLGA-amoxicillin-loaded layer formed on anodized Ti alloy as a hybrid material for dental implant applications

In this paper, the preparation of a functional hybrid coating loaded with a drug (amoxicillin) on a promising titanium alloy – Ti-15Mo alloy is presented. The titanium alloy surface was anodized in solution with bioactive compounds to obtain a porous oxide layer favorable for MG-63 osteoblast-like cell adhesion. Then, a poly(lactide-co-glycolide) (PLGA) loaded with amoxicillin layer was formed using a dip-coating technique to cover the oxide layer, without filling in all of the pores. The morphology of the surface was evaluated using scanning electron microscopy supported by 3D Roughness Reconstruction software. The surface treatment of the Ti-15Mo alloy surface caused the surface roughness to increase up to 1.71 μm. The anodization process caused the Ti-15Mo alloy surface to become slightly more hydrophilic; however, the formation of the PLGA layer loaded with drug increased the contact angle to 96.5° ± 2.2°, respectively. After 4 weeks of polymer layer degradation, the registered signals on the 1H NMR spectrum were identical to the signals registered for lactic acid (LAc), which confirms that the polymer layer was degraded within a short period of time. The concentration of drug released into the artificial saliva was investigated using high-performance liquid chromatography (HPLC) up to 12 h of coatings immersion. During the first hour of coating degradation in artificial saliva, and the concentration of the drug (13 μg/ml) was enough to inhibit bacterial growth of S. aureus and S. epidermidis. These results were confirmed by agar plate diffusion method and evaluation of the minimal inhibitory concentration (MIC). The cytocompatibility of the materials was determined using the osteoblast-like cells MG-63, and the viability and cell morphology (live/dead staining) were also evaluated. The results showed that amoxicillin influences the osteoblast-like MG-63 cells' behavior during cell culture, especially for the first few hours. The influence on the type of surface treatment on MG-63 cell behavior during 7 days of culture is discussed in this paper. To the best of our knowledge, this is the first time that a fast-degrading layer with amoxicillin has been deposited on previously anodized Ti surface. The formation of functional coating may find application as a cytocompatible coating to prevent bacterial adhesion on long-term implant surfaces.

Diffusivities and Atomic Mobilities in bcc Ti-Mo-Zr Alloys.

β-type (with bcc structure) titanium alloys have been widely used as artificial implants in the medical field due to their favorable properties. Among them, Ti-Mo alloy attracted numerous interests as metallic biomaterials. Understanding of kinetic characteristics of Ti alloys is critical to understand and manipulate the phase transformation and microstructure evolution during homogenization and precipitation. In this work, diffusion couple technique was employed to investigate the diffusion behaviors in bcc Ti-Mo-Zr alloys. The diffusion couples were prepared and annealed at 1373 K for 72 h and 1473 K for 48 h, respectively. The composition-distance profiles were obtained via electron probe micro-analysis (EPMA). The chemical diffusion coefficients and impurity diffusion coefficients were extracted via the Whittle-Green method and Hall method. The obtained diffusion coefficients were assessed to develop a self-consistent atomic mobility database of bcc phase in Ti-Mo-Zr system. The calculated diffusion coefficients were compared with the experimental results. They showed good agreement. Simulations were implemented by Dictra Module in Thermo-Calc software. The predicted composition-distance profiles, inter-diffusion flux, and diffusion paths are consistent with experimental data, confirming the accuracy of the database.

The effect of molybdenum on titanium’s castability in dental prosthesis applications: A numerical analysis

The ISO 22674 standard categorizes metallic materials that are suitable for dental appliances and restoration fabrication. Nickel, cadmium, and beryllium are classified as hazardous elements in this international standard. However, many alloys containing nickel and beryllium are used in dentistry as biomedical metallic materials. Numerous studies on the toxicity of nickel and beryllium have led to serious doubts about the biological reliability of these alloys. Titanium therefore attracts great interest due to its potential use in dental prostheses. Commercially pure titanium has biocompatibility, low density, great corrosion resistance, and mechanical strength at room temperature. In spite of its numerous desirable properties, it is hard to cast titanium because of its high melting temperature. In this study, the microstructure and castability of binary Ti–Mo alloys (2%, 4%, 6%, 8%) was investigated using numerical methods to evaluate their potential use in dentistry. ProCAST software was used to model the casting behavior.

Physicochemical, morphological, and biological analyses of Ti-15Mo alloy surface modified by laser beam irradiation.

Perform a physicochemical and morphological characterization of a Ti-15Mo alloy surface modified by laser beam irradiation and to evaluate in vitro the morphological response and proliferation of osteoblastic cells seeded onto this alloy. Disks were made of two different metals, Ti-15Mo alloy and cpTi, used as control. A total of four groups were evaluated: polished cpTi (cpTi-pol), laser-irradiated cpTi (cpTi-L), polished Ti-15Mo alloy (Ti-15Mo-pol), and laser-irradiated Ti-15Mo alloy (Ti-15Mo-L). Before and after laser irradiation of the surfaces, physicochemical and morphological analyses were performed: scanning electron microscopy (FEG-SEM), energy-dispersive spectroscopy (EDX), and X-ray diffraction (XRD). The wettability of the samples was evaluated by contact angle measurement. Murine preosteoblastic cells MC3T3-E1 were cultured onto the experimental disks for cell proliferation, morphology, and spreading analyses. Laser groups presented irregular-shaped cavities on its surface and a typical microstructured surface with large depressions (FEG-SEM). The contact angle for both laser groups was 0°, whereas for the polished groups was ≈ 77 and ≈ 78 for cpTi-pol and Ti-15Mo-pol, respectively. Cell proliferation analysis demonstrated a higher metabolic activity in the laser groups (p < 0.05). From the fluorescence microscopy, Ti-15Mo-L surface seems to induce greater cellular differentiation compared to the cpTi-L surface. The preliminary biological in vitro analyses suggested possible advantages of laser surface treatment in the Ti-15Mo alloy regarding cell proliferation and maturation.

First-principles study of phase stability and elastic properties in metastable Ti-Mo alloys with cluster structure

ABSTRACTThis paper provided a novel approach for evaluating phase stability and elastic properties in metastable Ti–Mo alloys with low Mo content by first-principles combined with cluster structure. In 54-atom body-centered-cubic supercell by substituting Ti atoms with 2–7 Mo atoms (7.1–23.0 wt% Mo), individual cluster structure of β-phase was constructed by ‘-Mo-Ti-Mo-’ cluster unit having the lowest cohesive energy. The distorted supercell was more stable than undistorted one at a low Mo content. With increasing Mo content, the density of state at Fermi level decreased, and bonding electron number increased, indicating β-phase stability was gradually promoted. Tetragonal shear elastic constant (C′ = (C11 – C12)/2), shear modulus (G111) and anisotropy factor (A = C44/C′) exhibited a fluctuation with Mo addition, while the change trend of A was opposite to C′ and G111. Calculated Young’s modulus exhibited similar changing trend to the C′, implying that the softening of C′ resulted in low Young’s modulus of β-phase. Measured Young’s modulus exhibited significant difference from calculated one, which was mainly caused by formation of α″-martensite and ω-phase. The values of C′, G111 and A were considered to associate with not only elastic properties of β-phase itself but also transition from β-phase to α″-martensite and/or ω-phase.

Microstructure and tensile properties of Ti-Mo alloys manufactured via using laser powder bed fusion

In this work, the dense Ti-7.5Mo sample (over 99.5%) was prepared by using laser powder bed fusion (L-PBF) from powder mixture of pure Ti and pure Mo. Through the use of mechanical mixture process, Mo particles present an uniform distribution. As the laser scanning speed decreases from 1700 mm/s to 1000 mm/s, the sample's relative density increases from 85.5% to 99.5%. The microstructural analysis indicates that Mo particle was mostly fully melted during laser melting. But, some large sized Mo particles were partial melted, which possesses gradient interface structure. Then, the tensile properties of as-fabricated samples under several laser scanning speed were determined. The results shows that the as-fabricated dense sample presents Young's modulus, ultimate tensile strength and strain at failure about of 70 GPa, 740 MPa and 9.2% respectively. Given to this low Young's modulus, which is approximate to bone of 30 GPa, the L-PBF processed Ti-7.5Mo shows great application potential in implant component.

Calcium phosphates of biological importance based coatings deposited on Ti-15Mo alloy modified by laser beam irradiation for dental and orthopedic applications

Ti-15Mo alloy samples were irradiated by pulsed Yb:YAG pulsed laser beam under air and atmospheric pressure. Sequentially, calcium phosphate coatings were deposited on the irradiated surfaces by the biomimetic method. The formation of calcium phosphates (CaP) under biological medium and SBF (Synthetic/Simulated Body Fluid) occurs in the presence of Ca2+ and PO43- ions, as well as ions such as: Mg2+, HCO3-, K+ and Na+, which facilitates the mimicking of the biological process. The biomimetic calcium phosphates-based surfaces were submitted to heat treatment conditions at 350 °C and 600 °C. The present study correlates four conditions of fluency (1.91, 3.17, 4.16 and 5.54 J/cm2, respectively) as established have a sufficient energy to promote ablation on the laser beam irradiated surfaces. Likewise, it has been demonstrated the processes of fusion and fast solidification from the laser beam irradiation, under ambient atmosphere, inducing the formation of stoichiometric (TiO2) and non-stoichiometric titanium oxides (TiO, Ti3O, Ti3O5 and Ti6O) with different oxide percentages depending on the fluency applied. Besides that, laser modification has allowed a clean and reproducible process, providing no traces of contamination, an important feature for clinical applications. The morphological and physico-chemical analysis indicated the formation of a multiphase coatings depending on the heat treatment temperature performed to 350 °C (ACP1–2, CDHA, HA phases) and 600 °C (CDHA, HA and β-TCP phases). It is worth noting multiphasic bioceramic systems has been gaining attention for biomedical applications. The laser beam irradiation associated to bioactive coatings of calcium phosphates of biological interest have shown to be promising and economically feasible for use in clinical applications.

Microstructure and Mechanical Properties of Ti-15Mo Alloy Prepared by ECAP

Microstructure and Mechanical Properties of Ti-15Mo Alloy Prepared by ECAP

Heterogeneous Precipitation of the α-Phase in Ti15Mo Alloy Subjected to High Pressure Torsion

Heterogeneous Precipitation of the α-Phase in Ti15Mo Alloy Subjected to High Pressure Torsion

Ti-Mo alloys: corrosion study in solutions simulating commercial gels

Regarding to the influence of chloride and fluoride ions on the corrosion resistance, the electrochemical behavior of Ti alloys has been deeply studied. In this work, the main goal was to investigate the electrochemical behavior of cp-Ti and Ti-Mo alloys containing 6, 10 and 15 wt% of Mo concentrations. All the samples were immersed in different solutions, such as 0.15 mol L-1 Na2SO4, 0.15 mol L-1 Ringer, 0.15 mol L-1 Ringer plus 0.036 mol L-1 NaF and 0.036 mol L-1 NaF. Simulating the commercial fluorinated gels, the NaF solutions naturally-aerated were prepared with 1450 ppm of fluoride ions. The electrochemical techniques applied in this work were the open-circuit potential, cyclic voltammetry, besides the technique for chemical identification, which was X-ray photoelectron spectroscopy. The formation and growth of TiO2 and MoO2 were identified, without pitting corrosion. The electrochemical stability and the corrosion resistance of the Ti-Mo alloys decreased in the solutions containing chloride and fluoride ions, with an appreciative decrease especially in the fluorinated medium. The Ti-Mo alloy with higher Mo content concentration was the material with higher corrosion resistance. Therefore, it is a promising candidate as a biomaterial, once the osseointegration needs a satisfactory corrosion resistance for being achieved.

Mechanical properties, in vitro corrosion resistance and biocompatibility of metal injection molded Ti-12Mo alloy for dental applications

A biocompatible Ti-12Mo alloy was fabricated by metal injection moulding (MIM) using non-spherical titanium, molybdenum powders and a purposely designed binder. The density, microstructure and tensile properties were characterized. This was followed by a detailed assessment of its in vitro corrosion and biocompatibility performances, compared with that of two commonly used titanium-based materials extra low interstitial (ELI) Ti-6Al-4V and commercially pure (CP) titanium. The MIM-fabricated Ti-12Mo alloy can achieve a wide range of mechanical properties through controlling sintering process. Specimens sintered at 1400 °C are characterized by fairly uniform near-β microstructure and high relative density of 97.6%, leading to the highest tensile strength of 845.3 ± 21 MPa and elongation of 4.15 ± 0.2% while the highest elastic modulus of 73.2 ± 5.1 GPa. Owing to the formation of protective TiO2-MoO3 passive film, the MIM-fabricated Ti-12Mo alloy exhibits the highest corrosion resistance including the noblest corrosion potential, the lowest corrosion current density and the highest pitting potential in four different electrolytes. The in vitro cytotoxicity test suggests that the MIM-fabricated Ti-12Mo alloy displays no adverse effect on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6Al-4V or CP Ti. These properties together with its easy net-shape manufacturability make Ti-12Mo an attractive new dental implant alloy.

Effect of Deformation Twinning in Metastable β-Type Ti-15Mo Alloys

This study was carried out to evaluate the effect of deformation twinning in Ti-15Mo alloys. The material was rolled to reduce the thickness by 88% and recrystallized at 900°C for 10 min. To observe deformation twinning, electron backscattering diffraction was applied, and the grain boundary characteristic distributions were analyzed. Application of rolling and recrystallization promoted development of texture with a {111}//ND component, which was a result of the lower phase stability. In particular, material subjected to tensile strain showed dense deformation twins with a component of {332} that promoted the strength, r, and n values without a significant decrease in elongation. These phenomena are attributed to the enhanced strain-hardening exponent due to deformation twinning.

Continuous microstructure evolution of ball rolled TWIP Ti[sbnd]15Mo alloy and its effect on phase precipitation behavior

A β-type Ti15Mo alloy with {332}〈113〉 twinning-induced plasticity (TWIP) effect was utilized to investigate the continuous microstructure evolution of β-matrix by ball rolling method. Precipitation behavior of α-phase and strengthening mechanism were examined in regions with different strain. Amounts of intersected twins were present in the slightly deformed region of β-matrix, and their area fraction decreased with an increase of distance from rolled surface. The β-matrix close to surface was heavily deformed to result in the formation of abundant subgrains and nanograins, which was caused by cooperative occurrence of twinning refinement, intragranular dislocation activities and subgrain rotation. Mechanical twins provided the preferential nucleation sites for plate-like α-phase with strong variant selection. Equiaxed α-phase preferentially nucleated at the boundaries of subgrains and nanograins with weak variant selection to form the ultrafine (α + β) duplex structure. Due to the formation of subgrains and nanograins as well as the strain hardening, strengthening became more significant than that by twinning refinement solely. Similarly, the ultrafine (α + β) duplex structure exhibited a better strengthening effect than that by precipitation of plate-like α-phase. The diversities of deformation microstructure combined with different precipitation behaviors of α-phase are desirable for controlling the mechanical properties of β-type TWIP titanium alloys.

Microstructure and micro-texture evolution of additively manufactured β-Ti alloys

This study focuses on the microstructural evolution in additively manufactured (AM) β titanium alloys due to solid-state phase transformations occurring during the reheating of previously deposited layers, directly influencing the uniformity of microstructure across the entire build. During the AM of titanium alloys of a wide variety of compositions, including α + β alloys such as Ti-6Al-4 V, and β alloys, when the laser or electron beam hits the sample, the grains in the previously deposited topmost layers either re-melt or transform into the β phase. Subsequently, during the cooling cycle, depending on the alloy composition, second-phase precipitation may occur within these layers via solid-state precipitation. The present study compares two binary β -Ti alloys, Ti-12Mo and Ti-20 V, that have been processed using laser engineered net shaping (LENS™), a directed energy deposition technique for AM. Compared to Ti-V, which exhibited grains of only the β phase in the as-built condition, the less β stabilized Ti-Mo had extensive second-phase α precipitation within the build. The location within the LENS™ build played a pivotal role in determining the size scale, area fraction, and morphology of the α precipitates. These changes have been attributed to the different thermal cycles experienced during the deposition process. Irrespective of the alloy composition, columnar grains were observed in the depositions with a strong [001]β texture along the build direction. In the Ti-12Mo alloy, wherein second phase α precipitation takes place, there was no significant α texturing, with all twelve variants forming.

Effect of Alkali Metal Cations on Electrochemical Behavior of Ti(III) Ions in Fluoride–Chloride Mixed Melts

1． Introduction Titanium metal has superior properties such as high strength-to-weight ratio, heat resistance, and corrosion resistance, etc. However, its high production cost and poor workability have been preventing the more widespread use of Ti metal. To utilize the superior properties and resolve the problems of Ti metal, electrdeposition of Ti from molten salt has been studied [1–5]. In previous studies, chloride [1,2], fluoride [3,4], and fluoride–chloride [5] molten salts were used as electrolytes. Generally, compact and smooth Ti films were obtained from fluoride melts such as LiF–NaF–KF [3,4] or fluoride-chloride melts such as NaCl–KCl–NaF [5]. The effect of F− ions on the electrodeposition reaction of Ti was also reported [6,7]. In these reports, the potential of Ti(III)/Ti(0) became negative when F/Cl or F/Ti ratio became higher. However, to the best of our knowledge, there have been no reports on the effect of cations on the electrochemical behavior of Ti ions in fluoride–chloride mixed melts. Recently, we reported the electrodeposition of Ti and the electrochemical behavior of Ti(III) ions in KF–KCl (45:55 mol%) melt at 923 K [8,9]. In the present study, we conducted the similar investigation in LiF–LiCl (45:55 mol%) melt at 923 K in order to reveal the effect of cations on the electrochemical behavior of Ti ions. 2. Experimental The experiments were conducted in LiF–LiCl (45:55 mol%) melt in an Ar-filled glove box at 923 K. Li2TiF6 (0.5 mol%) and Ti sponge (0.33 mol%) were added to the melt as Ti sources, and Ti (IV) ions were converted to Ti (III) ions by proportionation reaction. Mo flag and plate electrodes were used as working electrodes. The counter and reference electrodes were Ti rods. The potential of the reference electrode was calibrated by the deposition potential of Li metal on a Mo electrode. Samples produced by the galvanostatic electrolysis were analyzed using XRD after washing with water to remove the adhered salts. 3． Result and discussion Fig. 1 shows a square wave voltammogram (SWV) measured at frequency of 10 Hz at a Mo flag electrode in the LiF–LiCl melt after the addition of Li­2TiF6 (0.50 mol%) and Ti sponge (0.33 mol%). A single peak with a half width of 96 mV is observed at 1.22 V vs. Li+/Li. A small shoulder at 1.3 V is assumed to correspond to the formation of Ti–Mo alloy. The number of transferred electrons is calculated to be 2.9 from the peak half width. To confirm the electrodeposition of Ti, galvanostatic electrolysis was carried out at a current density of −50 mA cm-2 for 20 min. The potential during electrolysis was around 1.2 V. Fig. 2 shows an optical image of the sample. The deposit exhibits metallic luster. XRD analysis confirmed that the deposit is metallic Ti. From these results, the peak at 1.22 V in the SWV is confirmed to correspond to the reduction of Ti(III) ions to Ti metal. Since the potential of Ti(III)/Ti(0) is 0.32 V vs K+/K in KF–KCl (45:55 mol%) [9], the Ti(III)/Ti(0) potential in LiF–LiCl is much more positive even considering the difference between K+/K and Li+/Li potentials. This result indicates that the alkali cation species have an influence on the reduction stability of Ti(III) complex ions. R eferences [1] M. B. Alpert, F. J. Schultz, and W. F. Sullivan, J. Electrochem. Soc., 104, 555 (1957).[2] G. M. Haarberg, W. Rolland, A. Sterten, and J. Thonstad, J. Appl. Electrochem., 23, 217 (1993).[3] J. De Lepinay, J. Bouteillon, S. Traore, D. Renaud, and M.J. Barbier, J. Appl. Electrochem., 17, 294 (1987).[4] A. Robin, J. D. Lepinay, and M. J. Barbier, J. Electroanal. Chem., 230, 125 (1987).[5] V. V. Malyshev and D. B. Shakhnin, Mater. Sci., 50, 80 (2014).[6] N. Ene and S. Zuca, J. Appl. Electrochem., 25, 671 (1995).[7] J. Song, Q. Wang, X. Zhu, J. Hou, S. Jiao, and H. Zhu, Mater. Trans., 55, 1299 (2014).[8] Y. Norikawa, K. Yasuda, and T. Nohira, Mater. Trans., 58, 390 (2017).[9] Y. Norikawa, K. Yasuda, and T. Nohira, Electrochemistry, in press. doi:10.5796/electrochemistry.17-00082 Figure 1

Spatiotemporal characteristics of Portevin-Le Chatelier effect in Ti-Mo alloys under thermo-mechanical loading

The Portevin-Le Chaterlier (PLC) effect in Ti-12Mo and Ti-15Mo alloys has been investigated by using uniaxial tensile tests in a temperature range of 25–350 °C with an applied strain rate of the order of 10−3 s−1, coupled with a digital image correlation (DIC) method. The experimental results show an increase of the yield stress from 25 °C to 250 °C followed by a decrease. Moreover, PLC effect occurs above 250 °C and stress drop magnitude increases while the number of stress drops per unit time decreases with increasing the strain and temperature as well as decreasing Mo contents. These macroscopic features are related to the reduced intensity of interactions between ω phase particles and mobile dislocations as decreasing temperature and increasing Mo contents. Furthermore, a relatively higher temperature and lower Mo content tend to weaken the spatial cohesion of propagation bands and strengthen strain localization, leading to a change of PLC bands from type A to type B and the increase of strain rate within the PLC bands, which are related to the increased precipitation of ω phases. Additionally, the elongation at fracture is significantly influenced by PLC effect in Ti-Mo alloys.

Modification of the Ti15Mo alloy surface through TiO2 nanotube growth-an in vitro study.

In this study, ordered and uniform TiO2 nanotubular structures were obtained on the surface of the Ti15Mo alloy by anodic oxidation. The amorphous state of TiO2 nanotubes formed under different anodization conditions was investigated. Crystallization of TiO2 into anatase phase occurs during annealing at temperatures of around 400°C, whereas anatase to rutile transformation starts around 500°C and is completed at 800°C. Phase transformations in annealed samples led to morphological changes of tubular nanostructures, suggesting that the oxide layer formed at the nanotube/substrate interface serves as nucleation sites for more stable phases of TiO2. The proliferation of fibroblasts cells under annealing conditions of 450°C, and of untreated samples (control group), was evaluated after 1, 4, and 7 days in cell culture using fluorescence microscopy images. A gradual increase in the number and size of cells was observed, indicating a non-toxic alloy. There was also better surface coverage on anodized samples compared with the untreated group; as well as increased development of the cytoskeleton in samples after anodization. The results of this study showed that the growth of TiO2 nanotubular structures associated with annealing allow better cell adhesion on the Ti15Mo alloy surface.