Ti-29Nb-13Ta-4.6Zr Research Articles

Investigating micro-EDM machinability of Ti-35Nb-7Zr-5Ta (TNZT) alloy

ABSTRACT Titanium and its new-generation alloys are widely employed in high-end applications due to their special properties. Modern industries frequently use micro – Electro Discharge Machining (μ-EDM), a non-conventional machining technique that is especially useful for processing hard to machine materials like titanium alloys. μ-EDM can produce intricate shapes with excellent dimensional precision. The main emphasis of this work is an experimental analysis of the μ-EDM of TNZT alloy (Ti-35Nb-7Zr-5Ta) employing a tungsten carbide (WC) electrode. The results showed that with the increase in capacitance (C) 10nF to 100nF at Voltage (V) 80 V, the machining performance parameters such as material removal rate (MRR), overcut (OC), crater area, surface microhardness, and surface roughness increase by 6.38, 1.52, 4.66, 1.07, and 3.29 times, respectively. However, the circularity error of the µ-hole increases by 1.81 times. This study intends to show how the two key machining factors (C & V) influence significant machining performance parameters.

Computationally guided alloy design and microstructure-property relationships for non-equiatomic Ti–Zr–Nb–Ta–V–Cr alloys with tensile ductility made by laser powder bed fusion

Single-phase body-centered cubic refractory complex concentrated alloys (RCCAs), exhibit strength retention at temperatures above the melting points of conventional Ni-based superalloys. However, their lack of room temperature tensile ductility leads to cracks during processing and/or premature failure under mechanical loading when fabricated by laser-based metals additive manufacturing (AM). We present an alloy design framework for tensile ductility in non-equimolar RCCAs amenable to AM processing within the Ti–V–Cr–Nb–Zr–Ta system. First, density functional theory (DFT) and machine learning informed screening of alloy compositions were used to down-select ∼106 alloys with potential for tensile ductility. Next, Scheil solidification modeling was used to eliminate compositions most at risk for micro-segregation and solidification cracking based on the estimated freezing range of each alloy. This led to the design of two new, representative alloys: Ti0.4Zr0.4Nb0.1Ta0.1 and Ti0.486V0.375Ta0.028Cr0.111. These alloys were evaluated for rapid solidification defect formation using in-situ synchrotron melt pool imaging, fabricated via laser powder bed fusion (L-PBF) AM, and then characterized for processing defects, microstructure, and mechanical properties. Overall, both alloys achieved tensile yield strengths >800 MPa and failure strains >5 %. However, the occurrence of un-melted powders of high melting point elements likely resulted in premature failure during tensile straining. Considerations about mitigating this defect source are discussed and the role of local micro-segregation on ductility are elucidated. Overall, these results highlight the success of our framework, and show potential for laser-based AM-RCCAs with tensile ductility.

Additive manufacturing of a low modulus biomedical Ti–Nb–Ta–Zr alloy by directed energy deposition

While β titanium alloys have garnered extensive attention as a new generation of biomedical materials designed to mitigate stress shielding due to their low modulus, the realm of additive manufacturing for these alloys is still in its nascent stages. This study focuses on the additive manufacturing of Ti–35Nb–5Ta–7Zr alloy powder via directed energy deposition (DED). The primary objectives were assessing the feasibility of employing DED for this alloy powder and identifying processing parameters to achieve nearly dense components. Systematic exploration of the effect of various processing parameters was performed, and the resultant impact on the densification of the produced specimens was studied. Comprehensive analysis of the microstructure, mechanical properties, electrochemical behavior, and cell studies of fully dense sample coupons were performed. These fully dense samples were found to exclusively comprise the β phase of titanium, resulting in a reduced modulus of elasticity (approximately 44–47 GPa) resulting in high yield strength to elastic modulus ratio. Microstructural examinations revealed the presence of both columnar and equiaxed dendrites, with grains transitioning from columnar to equiaxed (known as CET). Electrochemical testing of the coupons indicated exceptional corrosion resistance in the additively manufactured TNZT alloy. Pre-osteoblasts cultured on the alloys showed good attachment, viability, and growth to confirm cytocompatibility. These findings unveiled the attainment of high strength, favorable ductility, a low elastic modulus, excellent corrosion resistance, and cytocompatibility in dense samples created via DED of Ti–35Nb–5Ta–7Zr. These outcomes hold immense significance for the production of patient-specific medical implants manufactured from β-Ti alloys.

Design and Development of Ti–Zr–Nb–Ta–Ag High Entropy Alloy for Bioimplant Applications

A new non‐equiatomic 35Ti–35Zr–20Nb–5Ta–5Ag at% high entropy alloy (HEA) is designed by combining the HEA concept with the properties required for bioimplants. Mechanical alloying is used to synthesize the HEA, which is then compacted at 550 and 700 MPa and sintered at 1300 °C. The phases, microstructure, and mechanical properties are investigated, and in vitro corrosion properties are studied in a simulated body fluid. After 20 h of mechanical alloying, a single body‐centered cubic (BCC) phase with a nanocrystalline size of 3.6 nm was formed. After sintering, the microstructure is composed of dual‐phase BCC structures: the major BCC 1 phase, the grain boundary BCC 2 phase, and the ultra‐fine equiaxed phase. The results of the micro‐indentation test indicate that the elastic modulus of the HEA is 84.4 ± 8.7 and 113.2 ± 13.36 GPa, and its Vickers microhardness is 3.47 ± 0.1 and 5.35 ± 0.2 GPa when it was compacted at 550 and 700 MPa respectively. The corrosion resistance tests reveal that HEA compacted at 700 MPa has higher corrosion resistance than commercial Ti6Al4V alloy. The developed Ti–Zr–Nb–Ta–Ag HEA has improved corrosion resistance and a lower elastic modulus, making it a potential candidate for bioimplant applications.

Real-time monitoring of Ti-Nb-Ta-Zr and commercially pure Ti interaction with H2O2 using atomic force microscopy and atomic emission spectroelectrochemistry

This study offers a new approach to analyze surface behavior of titanium biomaterials during their exposure to the H2O2-enriched fluid which simulates post-operative inflammatory conditions. In this work in situ AFM and AESEC tests were exploited to study the origin of initial inflammatory-induced degradation for commercially pure Ti (CP-Ti) and Ti-29Nb-13Ta-4.6Zr (TNTZ) alloy. Overall results indicate that initial interaction between H2O2 and TNTZ surface results only in dissolution of the alloy, while for CP-Ti both oxide formation and dissolution give important contribution to the degradation process. Proposed methodology yields insight into the origin of corrosion properties registered during standard electrochemical tests that are used to evaluate biomaterials.

Photocatalytic Activity and Antibacterial Properties of Mixed-Phase Oxides on Titanium Implant Alloy Substrates

Titanium alloys are commonly used for implants, but the naturally forming oxides are bioinert and not ideal for bacterial resistance or osseointegration. Anodization processes are a modification technique that can crystallize the oxides, alter oxide surface topography, and introduce beneficial chemistries. Crystalline titanium oxides are known to exhibit photocatalytic activity (PCA) under UVA light. Anodization was used to create mixed-phase oxides on six titanium alloys including commercially pure titanium (CPTi), Ti-6Al-4V (TAV), Ti-6Al-7Nb (TAN), two forms of Ti-15Mo (TiMo-β and TiMo-αβ), and Ti-35Nb-7Zr-5Ta (TNZT). Combined EDS and XPS analyses showed uptake of the electrolyte and substrate alloying elements into the oxides. The relative oxide PCA was measured using methylene blue degradation assays. CPTi and TAN oxides exhibited increased PCA compared to other alloys. Combined XRD and EBSD oxide phase analyses revealed an unfavorable arrangement of anatase and rutile phases near the outermost surfaces, which may have reduced PCA for other oxides. The relative Staphylococcus aureus attachment to each oxide was also assessed. The CPTi and TiMo-αβ oxides showed significantly reduced S. aureus attachment after 1 h of UVA compared to un-anodized CPTi. Cell culture results verified that the UVA irradiation did not negatively influence the MC3T3-E1 attachment or proliferation on the mixed-phase oxides.

Effect of hydroxyapatite coating thickness on inflammation and osseointegration of Ti–29Nb–13Ta-4.6Zr (TNTZ) implants

The study investigates the effect of Hydroxyapatite (HA) coating thickness on the inflammation and osseointegration properties of Ti–29Nb–13Ta-4.6Zr (TNTZ) implants for orthopedic implant applications. TNTZ screws were used as based samples, and the HA coating was deposited using an Electrophoretic Deposition (EPD) method to achieve various coating thickness. The thin (50–70 μm), medium (70–90 μm), and thick (90–110 μm) coating thicknesses were obtained by applying different voltage and time exposure during the EPD process, while the uncoated screw was used as the control sample. The screws were implanted into the right tibia of male Rattus norvegicus Wistar rats, and the animals were kept in cages and provide with ad libitum food for two weeks. After termination of the test animals, blood samples were collected to measure levels of Tumor Necrosis Factor-α (TNF-α) using an ELISA method, and a removal torque test was performed on the implanted screws. Additionally, tibial bone tissue around the implant area was collected for histopathology analysis. The result of the study indicate that HA coating thickness has an effect on TNF-α concentration, removal torque value, and new bone growth. The optimal thickness of the HA layer was found to be in the medium range (70–90 μm), resulting in low inflammation levels, relatively high osseointegration rates, and optimal new bone tissue growth. These finding are expected to be applicable in future orthopedic implant applications.

Effects of Thermo-Mechanical Processing on the Microstructure and Mechanical Properties of β -Type Titanium Alloys

This study investigates the microstructural evolution and mechanical behavior of severe cold-rolled β-type Ti-29Nb-13Ta-4.6Zr (TNTZ) alloys under systematic solution heat treatments (ST) at 1063 K for durations ranging from 5 to 60 minutes. This comprehensive analysis provides valuable insights into the microstructural and mechanical characteristics of TNTZ alloys under varying solution heat treatment durations, offering a foundational understanding for optimizing their application in engineering contexts. Microstructural analysis reveals that both solution-treated (ST) and cold-rolled (CR) samples exhibit a predominant single body-centered cubic (BCC) β phase, while cold-rolled and solution-treated (CST-Q) samples display a combination of β and martensite orthorhombic α'' phases. ST samples demonstrate equiaxed grains with an average diameter of ~72 μm, albeit with limited clarity. In contrast, CST-Q samples treated for over 10 minutes exhibit finer equiaxed grains within the 7-14 μm range. Hardness values increase with prolonged solution heat treatment, reaching approximately ~183 HV for ST and ~234 HV for CR. Moreover, hardness continues to rise with increasing treatment duration, reaching ~204 HV for CST10Q, ~229 HV for CST30Q, and ~242 HV for CST60Q. Mechanical properties, including tensile strength, yield strength, and elongation, vary across samples. ST shows values of ~710 MPa, ~610 MPa, and ~25%, CR with ~1305 MPa, ~395 MPa, and ~17.5%, CST5Q with ~1042 MPa, ~440 MPa, and 17.5%, CST10Q with ~1010 MPa, ~650 MPa, and 21%, and CST60Q with ~930 MPa, ~660 MPa, and ~21%. Fracture surfaces of all samples exhibit dimple structures and microvoid nucleation, indicative of ductile failure.

Study on Osseointegration Capability of β-Type Ti-Nb-Zr-Ta-Si Alloy for Orthopedic Implants.

Osseointegration is the basic condition for orthopedic implants to maintain long-term stability. In order to achieve osseointegration, a low elastic modulus is the most important performance indicator. It is difficult for traditional titanium alloys to meet this requirement. A novel β-titanium alloy (Ti-35Nb-7Zr-5Ta)98Si2 was designed, which had excellent strength (a yield strength of 1296 MPa and a breaking strength 3263 MPa), an extremely low elastic modulus (37 GPa), and did not contain toxic elements. In previous in vitro studies, we confirmed the good biocompatibility of this alloy and similar bioactivity to Ti-6Al-4V, but no in vivo study was performed. In this study, Ti-6Al-4V and (Ti-35Nb-7Zr-5Ta)98Si2 were implanted into rabbit femurs. Imaging evaluation and histological morphology were performed, and the bonding strength and bone contact ratio of the two alloys were measured and compared. The results showed that both alloys remained in their original positions 3 months after implantation, and neither imaging nor histological observations found inflammatory reactions in the surrounding bone. The bone-implant contact ratio and bonding strength of (Ti-35Nb-7Zr-5Ta)98Si2 were significantly higher than those of Ti-6Al-4V. The results confirmed that (Ti-35Nb-7Zr-5Ta)98Si2 has a better osseointegration ability than Ti-6Al-4V and is a promising material for orthopedic implants.

Analysis of physical, chemical, mechanical, and microbiological properties of Ti–35Nb–7Zr–5Ta and Ti–6Al–4V discs obtained by machining and additive manufacturing

The objective was to compare the physical, chemical, mechanical, and microbiological properties between discs (n = 10) of Ti–6Al–4V and Ti–35Nb–7Zr–5Ta (TNZT) obtained by Machining (M) and additive manufacturing (AM) by Laser Powder Bed Fusion technique to identify the influence of chemical composition and processing technique on material properties. Using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), x-ray diffraction (XRD), wettability, surface free energy, roughness by confocal laser microscopy and atomic force microscopy (AFM), Vickers microhardness (VM), and colony forming units (CFU) against S. aureus. Two-way ANOVA (p < 0.05) was applied. Higher roughness and irregularity were observed in the AM discs. The chemical composition of the EDX alloys was compatible with the concentrations expected and available in the literature. For TNZT the manufacturing technique interfered in the present phases (α and β) due to different cooling rates. The wettability and surface free energy of TNZT was higher than that of Ti–6Al–4V, and there was no significant difference for the manufacturing techniques. Ti–6Al–4V showed greater hardness than TNZT and the M technique greater than AM. There was no difference in S. aureus CFU between the groups. It was concluded that TNZT alloy showed higher hydrophilicity, surface free energy, roughness, lower hardness, manufacturing techniques that interfered in its phases, and no differences for CFU compared to Ti–6Al–4V. The AM technique generated more irregular and rough surfaces, and lower hardness, without significant changes concerning M in terms of chemical composition, wettability, surface free energy, and bacterial formation.

Mechanical, antibacterial and cytotoxic characteristics of nanolayered TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings

Titanium and titanium alloy materials are often made as medical implants. Surface properties of titanium medical implants play decisive roles for antibacterial and biological response and tissue biocompatibility. In this study, cathode arc evaporation (CAE) technology was used to deposit TiNb–Zr–Ta and nitrogen-doped TiNb–Zr–Ta coatings with nanostructures on the Ti–6Al–4V dental abutment screws. The deposited coatings were then oxidized at high temperature to produce different oxides on the surface of the coatings. The mechanical properties, antibacterial properties and biocompatibilities of the coatings were analyzed. The effect of coatings on the abutment screw loosening and removal torque between the abutment screw and the pure titanium implant fixture was studied by removal torque measurement. In addition, Staphylococcus aureus (S. aureus) was used for evaluating the antibacterial properties of coatings, and mouse fibroblasts (L929) were used for ISO 10993-5 cytotoxicity analyses to determine whether it had good biocompatibility.Nanolayered structures and multiphases of polycrystalline TiNb–Zr–Ta were obtained by co-deposition of Ta, Zr and TiNb. When small content of N was introduced, the TiNb–Zr–Ta(N) showed a polycrystalline TiNb–Zr–Ta where N atoms entered the metallic lattice at interstitial sites. After oxidation, oxide phases of Ta2O5, TiO2, Nb2O5 and ZrO2 were formed on the surface of TiNb–Zr–Ta and TiNb–Zr–Ta(N). Ta2O5 was obtained on the surface of the coating prior to other oxides such as TiO2, Nb2O5 and ZrO2. The deposited TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had high contact angle and exhibited a hydrophobic feature, while the annealed TiNb–Zr–Ta–O and TiNb–Zr–Ta(N)–O showed hydrophilicity. The deposited TiNb–Zr–Ta had similar hardness and Young's modulus values to that of the uncoated Ti–6Al–4V. When N was doped, the TiNb–Zr–Ta(N) had the highest hardness and Young's modulus. The hardness of the annealed TiNb–Zr–Ta(N) coating only decreased slightly due to the small oxide layer of ∼140 nm. Compared with the uncoated Ti–6Al–4V, TiNb–Zr–Ta serial coatings deposited on abutment screws had higher removal torques, which prevented the abutment screw of dental implant from loosening after long-term use. The biocompatibility of TiNb–Zr–Ta serial coatings was similar to that of the uncoated Ti–6Al–4V. In addition, the oxidized TiNb–Zr–Ta and TiNb–Zr–Ta(N) coatings had excellent antibacterial properties. It is speculated that the resulting Ta2O5 of both coatings may inhibit bacterial growth and improve the antibacterial effect. Based on the above advantages, the TiNb–Zr–Ta serial coatings are expected to have the potential to be applied to biomedical implants.

Tailoring Ti Grade 2 and TNTZ alloy surfaces in a two-step mechanical–chemical modification

ABSTRACT The aim of this work was to improve the surface properties of cp-Ti Grade 2 and β-Ti alloy TNTZ (Ti-29Nb-13Ta-4.6Zr) for biomedical applications. A hybrid surface treatment consisting of shot peening and chemical etching was conducted. Subsequently, the physicochemical properties and topography of the modified surfaces were analysed. Microhardness measurements of the shot-peened samples revealed a great increase in the surface hardness to the similar level as can be achieved for the ultrafine-grained and nanostructured materials. Roughness tests and microscopic observations showed significant topographical differences, depending on the material and modification process involved. Moreover, in this paper we demonstrate the influence of the substrate and treatments on the wettability. Obtained results confirmed that designed hybrid modification of Ti Grade 2 and TNTZ has significant potential for biomedical applications.

Damage performance of a shaped charge liner fabricated from Ti-29Nb-13Ta-4.6Zr alloy

The change of the liner material directly affects the penetration and damage performance of the shaped charge. In this paper, Ti-29Nb-13Ta-4.6Zr (TNTZ) was used as the charge liner. Autodyn software was used to analyze the jet formation of TNTZ liner, then static explosion test was conducted to analyze the penetration and damage performance of charge liners. The following conclusions were obtained: A charge liner structure was proposed for TNTZ alloy, the simulation shows that a jet with acceptable L/D ratio was formed, and the jet head velocity was around 6000 m/s. The TNTZ charge liner successfully ignited fuel tank after penetrating steel target due to chemical reaction. For the tests on C35 concrete targets, the TNTZ liner has horizontal damage effect which leads to penetration tunnel with large diameter, however the penetration depth is smaller compared to Cu liner. Such behavior makes TNTZ liner a good candidate as forward shaped charge of tandem warheads.

Novel strength-electrical conductivity synergy in Cu-based composites reinforced with TiZrNbTa high entropy alloy

An ultra-high strength TiZrNbTa (TZNT) high-entropy alloy (HEA) with good plasticity was attempted as a new reinforcing phase, which is introduced in the highly conductive Cu matrix to fabricate high-strength conductive composites. This work utilized a combination of a two-step ball milling method (first HEA mechanical alloying followed by fabrication of TZNT HEA/Cu hybrid powder) and a spark plasma sintering process to prepare the bulk TZNT HEA/Cu metal matrix composites (MMCs). Remarkably enhanced mechanical properties of the designed TZNT HEA/Cu MMCs with increasing TZNT contents were characterized while the electrical conductivity declined. Compared to the strength of the copper matrix, the strength of the fabricated 50 wt% TZNT/Cu specimens increased up to 340% induced by the second phase strengthening effect. The combination of grain boundary strengthening and dislocation strengthening contributed relatively less to the overall strength improvement of the composites. The TZNT/Cu composites were found to be a new insight into the high-strength conductive material preparation by choosing TZNT HEA with superior strength as hard secondary phase in copper matrix.

Bacterial response to Ti-35Nb-7Zr-5Ta alloy incorporated with calcium, phosphate and magnesium

High implant survival rates have been achieved in recent decades due to continual modifications in implant design and surface topography, however there is still an ongoing quest to control peri-implant bone loss. The objective of this work was to develop Ti-35Nb-7Zr-5Ta (TNZT) alloys, perform physicochemical and morphological characterization of their surface modified by electrolytic oxidative plasma technique with ions related to osseointegration and lastly evaluate bacterial colonization in vitro. Three groups were evaluated: C group (polished TNZT), CaP group (sodium β glycerophosphate + calcium acetate) and Mg group (magnesium acetate). Before and after anodizing the surfaces, physicochemical and morphological analyses were performed: scanning electron microscopy with field emission gun (FEG-SEM), energy dispersion spectroscopy (EDS), X-ray diffraction (DRX), wettability (goniometer) and roughness (rugometer). Controlled and treated specimens were contaminated with unstimulated saliva collected from 10 healthy volunteers. Then, biofilm samples were collected and up to 35 microbial species, including commensal and pathogenic microorganisms, were identified and quantified by the Checkerboard DNA-DNA Hybridization method. The CaP group modified the surface morphology in the form of pores, while the Mg group modified it in the form of flakes. The contact angle was significantly smaller in the CaP group. The average roughness was higher in the CaP and Mg groups. A smaller total amount of bacteria was identified in the Mg group and relevant differences were found in the microbial profile associated with different surface treatments. Therefore, considering the microbiological profile and for the prevention of peri-implantitis, the Mg group presented more satisfactory and encouraging results for the manufacture of dental implantsGraphical

Effect of the Ti/Ta ratio on the feasibility of porous Ti25+x-Nb25-Zr25-Ta25-x (X= 0, 5, and 10) alloys for biomedical applications

Non-toxic biomedical HEAs by powder metallurgy methods have been scarcely studied despite their promising mechanical and biological behaviors. This work studied the microstructural, mechanical, electrochemical, and ion release effects of the Ti/Ta ratio on three porous Ti–Nb–Zr–Ta (TNZT) alloys. The microstructure of the TNZT alloys consisted of semi-equiaxed and micrometric BCC-phases (matrix) with lower contents of HCP phase. Elastic moduli (82–91 GPa), hardness (373–430 HVN), ultimate bending (225–475 MPa), and tensile (119–256 MPa) strength, electrochemical corrosion (4.5–9.6 μm year−1), and ion release (toxicity, 0.9–1.1 μm year−1) were within acceptable limits for implant biomaterials. Increasing the Ti content (and decreasing Ta) was advantageous for improving mechanical strengthening and reducing the elastic modulus. The medium value of elastic modulus may be beneficial to reduce the mechanical mismatch between the implant and the organic tissue. However, the corrosion rate and metallic ion release increased as a function of the Ti content. Besides, the alloy with the lowest Ti content (highest Ta content) showed local corrosion. Based on the above, the porous TNZT alloys with medium and highest Ti contents (30 and 35 wt%) were demonstrated as promising candidates for biomedical implant applications.

Current and friction transients during tribocorrosion of a biomedical titanium alloy sliding against zirconia

The tribocorrosion mechanisms of a Ti–Nb–Zr–Ta (TNZT) alloy rubbing against a zirconia ball in a Phosphate Buffered Solution (PBS) were analyzed by considering the mechanical and chemical interactions that lead to the material degradation. To understand the governing mechanisms, tribocorrosion tests were carried out in a ball on flat contact and reciprocating tribometer applying two normal loads (6.7 and 11.2 N) and two different anodic potentials (400 and 1500 mV). Worn surfaces were characterized by SEM and FIB cross sections as well as surface analysis. During the tribocorrosion tests, transients consisting in simultaneous abrupt current increase and a decrease in the COF were found at different instants of the tests. Subsurface cracking as well as third body build up were observed. These different phenomena and their temporal sequence could be described by initial sliding tribocorrosion, including metal particle removal and surface oxidation, followed by the build-up of a protective third body. After a certain number of sliding cycles subsurface cracking due to strain accumulation beyond a critical level lead to the detachment of a large particles that reactivated the initial tribocorrosion process. This mechanistic view could be substantiated by a model based on a quantitative analysis of the results.

A comparative study on the machinability of β-type novel Ti29Nb13Ta4.6Zr (TNTZ) biomedical alloys under micro-milling operation

β-type Ti29Nb13Ta4.6Zr (TNTZ) alloy is a new-generation alloy that does not contain toxic/allergic elements. The alloys have low Young's modulus (⁓60 GPa) close to the cortical bone, providing excellent biocompatibility over familiar commercial CP Ti or Ti6Al4V ELI. Different macro/micro-machining methods can be used to obtain the final shape of Ti alloys and impact on the implant's bio ecosystem and performance. This study compared the micro-mill machining performance of the TNTZ alloys with commercial CP Ti and Ti6Al4V ELI. Machining experiments were performed under similar and different cutting speeds and constant feed rate conditions. In the study, cutting forces, surface roughness, burr size and tool wear were obtained. The results showed that the Fx cutting forces for TNTZ are about 3 and 2 times higher than for CP Ti and Ti6Al4V alloys, respectively. Depending on the increasing cutting distance, the surface roughness of CP Ti and Ti6Al4V materials followed a similar trend. However, the surface roughness values for TNTZ alloy are higher and decrease with increasing cutting distance. Burr widths for CP Ti and Ti6Al4V are similar, but the milling direction at which maximum burr occurs varies. In the TNTZ alloy, the burr width is about 3 times higher, and the burr occurred inside the slot, not at the edge of the machined slot. The predominant type of damage in milling Ti6Al4V and CP Ti materials is abrasive and adhesive. The dominant damage type in TNTZ alloy is chipping. Increasing the number of revolutions in TNTZ causes the cutting forces and burr width to increase.

Corrosion response and biocompatibility of graphene oxide (GO) serotonin (Ser) coatings on Ti6Al7Nb and Ti29Nb13Ta4.6Zr (TNTZ) alloys fabricated by electrophoretic deposition (EPD)

Corrosion response and biocompatibility of graphene oxide (GO) serotonin (Ser) coatings on Ti6Al7Nb and Ti29Nb13Ta4.6Zr (TNTZ) alloys fabricated by electrophoretic deposition (EPD)

Assessment of β stabilizers additions on microstructure and properties of as-cast β Ti–Nb based alloys

The novelty of the present work lies in elucidating the correlation of Moeq with mechanical and surface parameters. The Ti–15Nb (TN-15), Ti–40Nb (TN-40), Ti–33Nb–33Zr (TNZ-33), Ti–40Nb–40Zr (TNZ40) and Ti–35Nb–7Zr–5Ta (TNZT) alloys were obtained by casting. The alloys were formed by β-Ti grains with a micrometric morphology, except the as-cast TN-15 alloy formed by α + β. Adding Nb and Zr influenced the lattice parameters of phase β, as well as the crystal structure. Grain size (GS) decreased adding Nb and Zr following this relation: TN-40 > TNZ-33>TNZT > TNZ40. The roughness decreased with rising Nb and Zr contents being in the range of 1.3–3 μm, and it was possible to correlate it with the Moeq. The contact angle and free energy surface values were inversely proportional, and the as-cast TNZ40 alloy with smaller GS was less wettable (60) than TN40 (GS: 1423 μm). The mechanical properties decreased to Moeq of 14.9 wt% then their significantly went above this value, except for the as-cast TN-15 alloy (E: 65 GPa, microhardness: 264 HV) formed mainly by a hardener phase α. Both elastic modulus and microhardness showed the same tendency as the Moeq values and the cell parameter of phase β (aβ). The oxygen content was all in accordance with ASTM E1409-13 for applications as metallic biomaterials being in the range of 0.044–0.195 wt%.