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Titanium alloys, with the high specific strength and low elastic modulus, are currently the research focus of many applications. Various surface treatments have been applied with the intention of improving their wear and corrosion resistance. Micro-arc oxidation (MAO) technology originated from anodic oxidation (AO) technology, which has the advantages of simple process, high efficiency and environmentally friendly electrolyte. However, due to the micro-arc discharge effect, MAO coatings inevitably show the characteristic of high porosity. In this study, post-treatment of MAO coatings using AO was proposed to obtain a composite coating with both high hardness and low roughness and porosity thereby compensating for the defects of MAO coatings. After preparation, each sample was analyzed and characterized. The results indicated that AO was main conducted in the discharge channel of MAO coating and an amorphous phase coating with the matrix oxide as main component was grown in situ. The composite coating showed a slight increase in thickness and significant reduction in roughness than MAO coating and with superior wear and corrosion resistance. In conclusion, this study provides new idea and data support for improving the performance of MAO coatings, which is expected to be widely used in the field of surface treatment. [ABSTRACT FROM AUTHOR]

With increasing awareness of the circular economy, utilizing waste materials from titanium alloys for polymer composites offers numerous advantages. In this study, medical‐grade titanium alloy, Ti6Al4V chips were finely ground and mixed with epoxy resin to produce particulate‐reinforced composites. The tensile strength showed a 32% improvement compared to the neat epoxy. Similar results were observed for the flexural test, showing a 36% improvement in the composites. Moreover, a substantial 96% increase in thermal conductivity was observed, significantly expanding the potential application areas for the epoxy‐based composites. These improvements were achieved without the use of superfine nanoparticles or other expensive additives. This underscores the potential of a circular approach in the materials world, offering many new opportunities while promoting sustainability. Highlights: Circular utilization of titanium powders in polymer composites.Demonstrated effectiveness of titanium milling in composite production.Production of low‐cost, affordable composites suitable for diverse applications.Remarkable thermal conductivity values.Attainment of finely tuned mechanical properties. [ABSTRACT FROM AUTHOR]

Ti–6Al–4V is the most commonly used alpha–beta titanium alloy, making it the most prevalent among all titanium alloys. The processed material is widely employed in aerospace, medical, and other industries requiring moderate strength, a good strength-to-weight ratio, and favorable corrosion resistance. A microfinishing process on the titanium alloy surface was conducted using abrasive films with grain sizes of 30, 12, and 9 μm. Superfinishing with abrasive films is a sequential process, where finishing operations are performed with tools of progressively smaller grains. The surface topography measurements of the workpiece were taken after each operation. The experiment was in the direction of developing a new surface smoothness coefficient considering the number and distribution of contact points so as to properly evaluate the quality of the surface finishing. The results showed that the finest-grain films gave the most uniform contact points, thus offering the best tribological characteristics; the 9 LF (micron lapping film) tools gave the smoothest surfaces (Sz = 2 µm), while the biggest-grain films, such as the 30 FF (micron microfinishing film), were less effective since large protrusions formed. This is a suitable study to explore the optimization paths for the superfinishing of titanium alloys, with implications for improving the performance and longevity of components in critical industrial applications. [ABSTRACT FROM AUTHOR]

Because of its excellent mechanical qualities and weldability, titanium alloy is used in many different biomedical applications. Wire electrical discharge machining may be used to machine materials with such greater strengths and intricate forms. Using Taguchi-data envelopment analysis-based ranking (DEAR) approach and zinc-diffused coated brass wire electrode to improve Titanium alloy machining was the goal of this research project. The quality metrics that were taken into consideration were surface roughness, kerf width, and material removal rate. Among the selected factors, with an error of 2.7%, the optimal configuration of input factors was determined to be 130 µs (Ton), 40 µs (Toff), 50 V (SV), 6 A (IP), and 8 kg (WT). Due to its relevance in the process of deionization, the Ton is the highest influential parameter for creating quality measurements. [ABSTRACT FROM AUTHOR]

It is highly essential to enhance the micro EDM process while machining titanium specimens. The utilization of coated electrode and adaptation of optimization algorithms in the process can enhance the material removal mechanism. In the present work, an attempt was made to find the influence of TiN coated tungsten carbide electrode in micro EDM process while machining titanium alloy specimens. It was also attempted to adopt DEAR-based optimization in the process. The TiN coating can produce lower TWR with better surface quality than uncoated tungsten carbide electrode. The capacitance has higher influential nature in µ-EDM since it controls the charging and discharging process during the spark formation across discharge gap. It was found that voltage (Level 3), capacitance (Level 3), and the tool rotation (Level 2) can create better quality measures under the prediction error of 2.3%. The optimal combination can enhance the machining accuracy with tiny craters formation. [ABSTRACT FROM AUTHOR]

Implant surgeries are increasingly challenging due to their rising number. Achieving the desired biomaterial surface properties to ensure a strong bond with human tissue is a significant issue. This study investigates the influence of ultrasound (US) during the micro-arc oxidation (MAO) process on Ti13Zr13Nb bio-alloy, an area not previously explored, to enhance titanium alloy coatings' properties for biomedical applications. Porous calcium-phosphate-based coatings were successfully deposited on Ti13Zr13Nb using MAO and ultrasound micro-arc oxidation (UMAO). Various properties such as morphology, chemical composition, topography, wettability, surface free energy, thickness, adhesion to the substrate, as well as mechanical and corrosion characteristics were thoroughly analyzed. Cytocompatibility was assessed using human osteoblasts. Using US during the MAO process increased coating roughness (up to ~ 17%), core height (up to 22%), isotropy (up to 17%), thickness (up to ~ 46%), and hardness (up to ~ 18%), depending on MAO parameters and US mode. Optimal coating performance was achieved at 136 mA, 600 s, and a sinusoidal US setting, resulting in the highest isotropy (~ 79%) and rutile quantity (2.6%), the lowest elastic modulus (~ 57 GPa), and the contact angle of ~ 70°, all of which could have contributed to enhancing osteoblast viability in vitro. This study, for the first time, underscores the importance of using the US during the MAO in tailoring the Ti13Zr13Nb for specific biomedical applications. [ABSTRACT FROM AUTHOR]

ABSTRACT X‐ray computed tomography (XCT) is extremely useful for the non‐destructive analysis of additively manufactured (AM) components. AM components often show manufacturing defects such as lack‐of‐fusion (LoF), which are detrimental to the fatigue life of components. To better understand how cracks initiate and propagate from internal defects, we fabricated Ti‐6Al‐4V samples with an internal cavity using electron beam powder bed fusion. The samples were tested in high‐cycle and very high‐cycle fatigue regimes. XCT was used to locate crack initiation sites and to determine characteristic properties of cracks and defects with the aid of deep learning segmentation. LoF defects exposed to the outer surface of the samples after machining were found to be as detrimental to fatigue life as the internal artificial defects. This work can benefit industries that utilize the AM of high‐strength, lightweight alloys, in the design and manufacturing of components to improve part reliability and fatigue life. [ABSTRACT FROM AUTHOR]

ABSTRACT This study investigated the fatigue fracture mechanisms and life prediction of clinched joints made from titanium alloy TA1. The fatigue tests revealed that TA1 titanium alloy clinched joints exhibited failure characterized by fracture of the lower plate at three distinct fatigue load levels. Additionally, finite element analysis indicated that cold work hardening enhanced the fatigue performance of these joints. Observations of fracture surfaces using scanning electron microscopy identified the crack source and its propagation path, which correlated with the location of maximum principal stress from the finite element simulations. Fretting wear was also observed in this critical region. Furthermore, fatigue life predictions for TA1 titanium alloy clinched joints were made using Paris' law and the local strain approach. Both methods closely matched experimental results across different fatigue life intervals. Overall, the local strain approach exhibited superior predictive capability compared to Paris' law, taking into account various influencing factors. [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, additive manufacturing (also known as 3D printing) has gradually become the mainstream method for producing titanium alloy brackets for removable partial dentures. Heat treatment, as an important method to improve the mechanical properties of 3D printed titanium alloys, has become a current hot topic of attention. OBJECTIVE: To summarize the main heat treatment technologies currently applied to 3D printed titanium alloy specimens (including annealing, solution aging, hot isostatic pressing, and other heat treatments) and their effects on the mechanical properties and microstructure of 3D printed titanium alloy specimens, providing a theoretical basis for improving the heat treatment technology of removable partial denture titanium alloy supports. METHODS: A computer search was conducted on research materials related to 3D printed titanium alloy heat treatment in databases such as CNKI, PubMed, and ScienceDirect. The search period was from 2012 to 2023. A total of 61 articles were selected based on inclusion and exclusion criteria. RESULTS AND CONCLUSION: (1) Using conventional annealing techniques to treat 3D printed titanium alloy specimens, keeping them at 500-900 °C for 2-4 hours, can effectively increase the elongation of 3D printed titanium alloy specimens. (2) Compared to conventional annealing techniques, solid solution aging treatment is more complex, and the titanium alloy specimens after solid solution aging treatment exhibit outstanding yield strength and better corrosion resistance. However, the 3D printed titanium alloy specimens after solid solution aging treatment have no advantage in terms of ductility. (3) Hot isostatic pressing treatment can reduce the internal defects of 3D printed titanium alloy specimens, significantly increase the elongation of 3D printed titanium alloy specimens, and increase their fatigue life. (4) Rapid heat treatment can significantly improve the elongation of 3D printed titanium alloy specimens, and the speed is faster. In terms of elongation improvement and heat treatment efficiency, it has more advantages than conventional annealing in the past. (5) The improvement of elongation of 3D printed titanium alloy specimens by cyclic heat treatment exceeds that of conventional annealing. Cyclic heat treatment can significantly improve the grain structure of 3D printed titanium alloy specimens, but the heat treatment time is too long and the efficiency is low. [ABSTRACT FROM AUTHOR]

Titanium alloys are applied in oil and gas development and transportation to improve conditions because of their high specific strength and corrosion resistance. However, the disadvantage of poor wear resistance has become an obstacle to developing titanium alloys. The friction and wear properties of pure titanium TA3 and titanium alloy TA10 were tested under different loads and different friction forms using a reciprocating friction and wear tester. Moreover, the erosion resistance of pure titanium TA3 and titanium alloy TA10 was studied using a gas–solid erosion tester. The results show that the wear rate of TA3 and titanium alloy TA10 increases with increasing friction load. Under a load of 50 N, the mass losses of TA3 under dry friction and wet friction were 0.0013 g and 0.0045 g, respectively, while the mass losses of TA10 were 0.0033 g and 0.0046 g, respectively. While the load increased to 70 N, the mass loss of TA3 was even greater, reaching 0.0065 g, and the mass loss of TA10 was 0.0058 g. The wear forms of TA3 and TA10 include abrasive wear, adhesive wear and oxidation wear. The joint action of various friction forms leads to the loss of materials. Under the simulated working conditions, the erosion rates of TA3 and TA10 were 1.01 × 10−3 g/s and 0.94 × 10−3 g/s. The erosion mechanism is the same, including plowing, indentation and cracking. [ABSTRACT FROM AUTHOR]

This study establishes an empirical model for a four-flute cylindrical helical end mill, utilizing orthogonal cutting tests on a Ti-6Al-4V block as the machining workpiece. The reliability of the model was confirmed through a titanium alloy side milling experiment. Results demonstrate that the empirical index model for predicting the main cutting force error falls within the range of 4.19 %–10.0 %, providing an effective tool for cutting force prediction. The specific influence distribution trends of cutting parameters, including milling speed, feed per tooth, and depth of cut, on the cutting force through two-step milling of profile walled surface of titanium alloy were analyzed. The results reveal that the milling force in the first step exhibits a discernible upward trend with the increase of feed per tooth and radial depth of cut. Among the cutting parameters employed in the first step, the cutting speed exerts the most significant influence on the cutting force in the second step. [ABSTRACT FROM AUTHOR]

This article explores the use of deep learning, specifically artificial neural networks, to optimize the parameters of laser shock peening in the Ti-6Al-4V alloy. Laser shock peening is a technique that introduces compressive residual stresses to improve the fatigue properties of materials. The authors develop a neural network model that accurately predicts residual stresses and depth of the modified layer. The model can be used to identify optimal processing parameters for achieving maximum depth and compressive stresses. The study concludes that the neural network predictions align with experimental results. [Extracted from the article]

In this paper, experimental analysis was performed during micro-electrical discharge machining (micro-EDM) of titanium alloy Ti–6Al–4V (grade 5) using three types of tools viz. copper (Cu) tool, tungsten carbide (WC) tool, and synthetic graphite (Gr) grade three tool. The main process parameters were taken as (a) pulse on time ( T on ), (b) pulse off time ( T off ), (c) voltage (V), and (d) capacitance (C). The output responses were taken as the material removal rate (MRR) and tool wear rate (TWR). Taguchi method coupled with grey relational analysis (GRA) (L 1 6 orthogonal array) technique was applied to optimize the input process parameters for both the responses. Scanning electron microscopy (SEM) analysis of the workpiece and tool was also performed to investigate the morphology of the machined surface and tool surface. Energy-dispersive spectroscopy (EDS) analysis was performed to investigate the elemental composition of the machined surface. The experimental finding reveals that tungsten carbide is the most suitable tool material for machining the chosen workpiece for obtaining optimal MRR and TWR. The optimum condition for the copper tool was found as 180 V, 1000 pf, 10 μ s ( T on ), and 10 μ s ( T off ). Meanwhile, the optimum parametric condition for tungsten carbide and graphite tools was found to be the same as 240 V, 100 pf, 20 μ s ( T on ), and 5 μ s ( T off ). [ABSTRACT FROM AUTHOR]

Through the optimization of tool parameters and the wedge shape, titanium alloy workpieces free of internal and external defects were formed by flat cross wedge rolling (CWR) adopting tools without surface grooves. Firstly, the thermomechanical coupled model of CWR for TC11 (Ti-6.5Al-3.5Mo-1.5Zr-0.3Si) titanium alloy was established in the finite element (FE) software DEFORM-3D, and the effects of forming angle α, stretching angle β, and section reduction Ψ were studied. The results showed that in the conventional empirical range of tool parameters, the defect-free workpiece is hard to be rolled by the typical tool structure. To optimize the forming quality of rolled workpieces, a modified tool structure was proposed by introducing an inclined plane with a width of λ (2–5 mm) on the top of the wedge shape and revising the side wedge plane α to a combination of two inclined planes α1 and α2 (α ≥ α1 > α2). Simulations and experiments demonstrated that the modified tools without surface grooves can achieve TC11 alloy workpieces with smooth surface. When the distance between the top and bottom tools is too large, the rolled workpiece axis is prone to being bent, and the gap from the top tool to the billet should be controlled in the range of 0–0.2 mm to ensure its straightness. Finally, the necking-free TC11 alloy rolled workpieces (Ψ = 67.9% and Ψ = 82.3%) with smooth surface and excellent internal quality were manufactured by IM500 flat CWR mill at 900 °C, 500 mm/s. [ABSTRACT FROM AUTHOR]

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Foundry Technology (1000-8365) is the property of Foundry Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The fracture strength was compared in a scratch test of coatings based on the ZrN system with the introduction of Ti, Nb and Hf, which were deposited on a titanium alloy substrate. The coatings were deposited using Controlled Accelerated Arc (CAA-PVD) technology. In coatings that simultaneously include Zr and Ti, a nanolayer structure is formed, while in coatings without Ti, the formation of a monolithic single-layer structure is observed. The comparison was carried out according to two parameters: adhesion strength to the substrate and overall coating strength. The (Zr,Hf)N coating showed better resistance to destruction, but had worse adhesion to the substrate. As a result, although the coating is retained directly in the scribing groove, a large area of delamination and destruction is formed around the groove. The (Ti,Zr,Nb)N coating, with its somewhat lower strength, has a high adhesion to the substrate; no noticeable delamination is observed along the groove boundary. In this paper, not only is the fracture resistance of various coatings deposited on a titanium alloy substrate compared, but the nature of this fracture is also investigated depending on the composition of the coatings. [ABSTRACT FROM AUTHOR]

Numerical simulations of the cutting process play a key role in manufacturing and cost optimization. Inherent in finite element analysis (FEA) simulations is the correct description of material behavior during machining. For this purpose, various material models are used to describe the behavior of the material in the range of high deformation, high temperature values, and high strain rates. Very often the Johnson–Cook (JC) material model is used for this purpose; however, the correct determination of the material constants of this model is a key aspect. Therefore, this paper presents a procedure for determining the material constants of the JC model using an analytical method based on normalized tensile and compression testing of the material for different strain rates over a wide temperature range. After determining the material constants, the authors conducted numerical simulations of the orthogonal turning of Ti6Al4V titanium alloy using the obtained constants. Validation of the obtained results with those obtained in experimental studies was also carried out. The outcomes demonstrated that the difference between FEM simulation and experimental tests did not exceed 0.02 mm (14%) in the case of chip thickness,. Much smaller differences were obtained for the temperature in the cutting zone, where the maximum difference was about 45 °C (4%). Comparing the components of the cutting force, we found that, in the case of the main cutting force, in most cases, the differences did not exceed 70 N (8%). After the verification of the obtained results, it was also found that the determined material constants of the Johnson–Cook model can be successfully used in FEM modeling of the cutting process of Ti6Al4V titanium alloy for the adopted range of values of technological parameters. [ABSTRACT FROM AUTHOR]

Characterization of hot deformation behavior of Ti-6Al-4V-0.5Ni-0.5Nb titanium alloy was investigated through isothermal compression at various temperatures from 750 to 1 050 °C and strain rate from 0.01 to 10 s−1. The isothermal compression experiment results showed that the peak stress of Ti-6Al-4V-0.5Ni-0.5Nb titanium alloy decreased with the temperature increasing and the strain rate decreasing. The softening mechanism was dynamic recovery below Tβ and changed to dynamic recrystallization above Tβ. The arrhenius-type relationship was used to calculate the constitutive equation of Ti-6Al-4V-0.5Ni-0.5Nb alloy in two-phase regions. It was found that the apparent activation energies were 427.095 kJ·mol−1 in the α+β phase region and 205.451 kJ·mol−1 in the β phase region, respectively. On the basis of dynamic materials model, the processing map is generated, which shows that the highest peak efficiency of power dissipation of 56% occurs at about 1 050 °C/0.01 s−1. It can be found in the processing maps that the strain had significant effect on the peak region of power dissipation efficiency of Ti-6Al-4V-0.5Ni-0.5Nb alloy. Furthermore, optimized hot working regions were investigated and validated through microstructure observation. The optimum thermo mechanical process condition for hot working of Ti-6Al-4V-0.5Ni-0.5Nb titanium alloy was suggested to be in the temperature range of 950–1 000 °C with a strain rate of 0.01–0.1 s−1. [ABSTRACT FROM AUTHOR]

A titanium alloy collision friction ignition device was used to conduct collision and continuous friction between TC4 titanium alloy rotating rod and TA7 and other titanium alloy collision samples. Combined with SEM and other microscopic analysis, the anti-ignition performance and products of TA7 and TC11 titanium alloys were studied, and the experimental results under this special friction condition were obtained. The research results show that the friction contact pressure Puff and the combustion chamber pressure P can be effective test parameters to evaluate the titanium alloy impact ignition process. The critical ignition curves of the three titanium alloys drawn based on Pf-P are all linear laws, and the anti-ignition performance is: TC11 > TA11 > TA7. Microscopic analysis of the titanium alloy after impact ignition shows that the combustion reaction zone of the titanium alloy consists of four regions: the combustion product zone (CPZ), the oxide zone (OZ), the heat-affected zone (HAZ), and the friction product zone (FPZ) in total. The multi-layer structure of Al2O3 formed by TC11 after ignition is conducive to blocking the mutual diffusion of Ti, O and other elements, which is the main reason for its superior anti-impact ignition performance. [ABSTRACT FROM AUTHOR]

This study investigated the development of Ti-Ta-Cu alloys via selective laser melting (SLM) for potential prosthetic applications. Ti-Ta-Cu alloys with 10, 15, and 20 wt.% Ta were fabricated using in situ alloying of elemental powders. We examined the effects of Ta content and SLM processing parameters on microstructure, phase composition, mechanical properties, and corrosion resistance. X-ray diffraction analysis revealed an increase in β-phase content with increasing Ta concentration. Microstructural analysis showed a dendritic structure in Ta-rich areas, with remelting strategies improving chemical homogeneity and Ta dissolution. The Ti-20Ta-5Cu alloy exhibited the best balance of strength and ductility, with an ultimate tensile strength of 1011 MPa and elongation of 5.7%. All compositions demonstrated lower elastic moduli (103–109 GPa) compared to traditional titanium alloys. Microhardness values were highest for Ti-15Ta-5Cu, ranging from 359 to 410 HV0.5 depending on SLM parameters. Corrosion testing in Hank's solution showed improved pitting resistance for Ti-15Ta-5Cu and Ti-20Ta-5Cu compared to Ti-10Ta-5Cu. The study demonstrates the feasibility of producing Ti-Ta-Cu alloys with tailored properties via SLM, offering potential for customized prosthetic applications with improved biomechanical compatibility and functionality. [ABSTRACT FROM AUTHOR]

The growing use of titanium alloys has led to the gradual replacement of traditional processing methods by laser cutting technology, making it the preferred method for processing titanium alloy plates due to its high efficiency, precision, and adaptability. In this review, the characteristics of laser cutting technology and its application in titanium alloy plate processing are summarized, outlining several aspects of the cutting process, microstructure, and mechanical properties of the material after cutting, along with simulation predictions. Previous research categorized laser-cutting input parameters into beam parameters and process parameters, with the commonly used parameters being the laser power, cutting speed, and gas pressure. Various parameter combinations can achieve different cutting qualities, and seven indices can be used to evaluate the cutting process, with the surface roughness and slit width serving as the most common indices. Different auxiliary gases have shown a significant impact on the laser cutting quality, with commonly used gases consisting of nitrogen, argon, and air. Argon-assisted cutting generally results in better surface quality. Due to the rapid temperature change, the titanium alloy microstructure will undergo a non-diffusive martensitic phase transformation during laser cutting, producing a heat-affected zone. Experimental studies and simulations of the mechanical properties have shown that the occurrence of a martensitic phase transformation increases the hardness and residual tensile stress of the material, which reduces the fatigue strength and static tensile properties. In addition, studies have found that the more streaks appear on the cut surface, the lower the fatigue strength is, with fatigue cracks arising from the stripes. Hence, the established analytical solution model and three-dimensional finite element model can effectively predict the temperature distribution and residual stress during the cutting process. This can provide a better understanding of the high residual stress characteristics of the cutting edge and the stripe formation mechanism, allowing researchers to better explore the mechanism of laser cutting. [ABSTRACT FROM AUTHOR]

The coatings of ZrN, (Zr,Ti)N, (Ti,Zr,Hf)N and (Ti,Zr,Nb)N deposited on the titanium alloy substrate were compared. The wear resistance in the pin-on-disk test together with the Al2O3 indenter and the corrosion resistance in 3.5% NaCl solution were studied. It was found that the (Zr,Nb,Ti)N coating has the best resistance to wear, but has low corrosion resistance. The (Ti,Zr,Hf)N coating, on the contrary, has the best corrosion resistance, but low resistance to wear. The ZrN coating has good corrosion resistance combined with good resistance to wear. This coating is best suited for use in friction conditions with a ceramic counterbody under the influence of seawater. An important resource for increasing the properties of coatings is increasing their adhesion to the substrate, which can be achieved in two combined ways: (1) complete removal of the original oxide layer from the surface of the substrate and (2) the use of optimal compositions of the adhesive sublayer, which have not only high adhesive properties in relation to both the substrate and the coating, but also high strength. While the introduction of Nb into the ZrN coating composition increases wear resistance and the introduction of Hf increases corrosion resistance, the ZrN coating without additives best resists wear and corrosion simultaneously. [ABSTRACT FROM AUTHOR]

Post-processing techniques can efficiently improve the surface quality, address microstructural defects, and optimize mechanical properties in additively manufactured parts. Surface severe plastic deformation processes such as ultrasonic nanocrystal surface modification (UNSM) integrated with localized laser heating were explored to enhance the surface properties, microstructure as well as the fatigue crack growth properties (FCG) in both directions of built. We successfully induced greater plasticity flow and achieved beneficial refinement of the surface grain structure by precisely controlling the heat and impact energies during surface treatment process. The LA-UNSM process, with the parameters utilized in this study considerably decreased the FCG rates of treated samples, when compared to samples without surface treatment. Improved fatigue crack growth properties along vertical and horizontal orientations after the post-process treatment were attributed to the induced-microstructural changes, improved surface quality, induced compressive residual stresses through gradient structure deformation layer that was prepared on the surface of the material. The fractographic analysis revealed that the cracks mostly originated from the pores in the as-produced state. This observation shows a clear correlation between the surface treatment performed and a substantial improvement in fatigue crack growth resistance. [ABSTRACT FROM AUTHOR]

Titanium alloys are mostly used in high temperature and high pressure, which requires its high mechanical properties and corrosion resistance. As a good surface modification technology, arc surface cladding has been applied in various fields. In this study, the gas tungsten arc welding was used to clad titanium alloy and the nitrogen gas with different contents were added in the shielding gas. During the cladding process, the TiN strengthening phase was formed in the cladding layer. The effects of different nitrogen flow rates on the microstructure and properties of the cladding layer were studied. The scanning electron microscope (SEM) and the x-ray diffractometer (XRD) were used to observe microstructure and identify the formed phases. The mechanical properties and corrosion properties were studied by Vickers hardness and electrochemical experiments. The results show that after adding nitrogen, the grain size becomes smaller and the hardness increases from 247 to 363 HV. The formation of TiN also improves the pitting corrosion resistance of the cladding layer. The corrosion resistance of the cladding layer was the best when the nitrogen flow rate was 0.4 L/min. Therefore, adding suitable nitrogen gas in the titanium alloy arc cladding process can significantly improve the performance of the cladding layer. [ABSTRACT FROM AUTHOR]

This study focuses on the effect of a plasma nitriding (PN) process on the thermal stability of nanocrystalline on the surface of Ti-6Al-4 V (Ti64) titanium alloy, which is printed by selective laser melting (SLM) and subsequently treated by laser shock peening (LSP). The microstructure evolution of SLM-Ti64 titanium alloy treated sequentially by LSP and PN at different annealing temperatures was observed by X-ray diffraction, differential scanning calorimeter, scanning electron microscope, and transmission electron microscope. The results show that the average size of SLM-Ti64 alloy treated by LSP is 49.7 nm, even at 600 °C nanocrystals maintain thermal stability, which is attributed to the strong hinder effect of high-density dislocations on grain boundary migration. The microstructural characterization indicates that the nitrided layer is mainly composed of nanostructured TiN phase by PN at 600 °C, and the thermal stability of nanocrystals was further increased to 700 °C compared without nitriding, which is attributed to dispersed nanoscale TiN precipitates hindering the migration of grain boundaries by Zener pinning effect. Our work provides a method of preventing nanocrystalline coarsening in Ti64 alloy by PN. [ABSTRACT FROM AUTHOR]

This study investigated the potential of a fluorinated boron nitride nanosheets (F-BNNSs)-based coating as a hot-forming lubricant for titanium alloys. The F-BNNSs were prepared through wet ball milling with hexagonal boron nitride (h-BN) powder and ammonium fluoride (NH4F), and the coatings were deposited by the spray method. The tribological behavior of coatings on pure titanium (TA1)/silicon nitride (Si3N4) frictional pairs was examined at 800 °C. The results demonstrated that F-BNNSs coatings exhibited excellent thermal stability, with the F-BNNSs3 coating (the mass ratio of h-BN to NH4F of 1:3) exhibiting the best tribological performance. The average coefficient of friction (COF) and wear rate reduced by 15 and 79% compared with the hexagonal boron nitride nanosheets (h-BNNSs) coatings, respectively. The excellent tribological properties of F-BNNSs coatings were attributed to the lower interlayer shear force, nanostructure, and interfacial behavior, which contribute to the formation of self-lubricating and friction-induced reaction films. Therefore, the F-BNNSs coating has shown potential application in the field of titanium alloy hot-forming. [ABSTRACT FROM AUTHOR]

In order to deeply understand the wear mechanism of the ball end mill in the helical milling process, the TiAlN coated carbide ball end mill is used for the machining of titanium alloy under dry cutting conditions, focusing the influence of tool wear on the cutting process and hole-making quality. Firstly, the geometry of the ball end mill and the material removal process during the helical milling process are discussed. Secondly, based on the different zones, tool microscope, electron microscope, and energy spectrum are used to detect the tool wear, so as to clarify the tool wear mechanism, and then explore the relationship between axial cutting force, radial cutting force, cutting temperature, and tool wear, thus the influence of the tool wear degree on the cutting process is analyzed. Finally, the changes of hole-making quality with different tool wear degrees are studied from the perspectives of geometry, machining defects, and exit burr of the hole-making, respectively. The results show that in order to get better hole-making quality, the magnitude of cutting force and cutting temperature should be controlled to increase the tool life in the normal wear stage. [ABSTRACT FROM AUTHOR]

Titanium (Ti) alloys have been widely used in biomedical applications due to their superior mechanical, physical, and surface properties, while improving their tribological properties is critical to widening their biomedical applications in the current era. The present review examines the recent progress made in enhancing the tribological performance of titanium alloys and titanium matrix composites for biomedical purposes. It specifically focuses on the progress made in biomedical coatings, mechanical surface treatment, and developing titanium matrix composites in terms of their processing, tribological testing conditions, and characterization. Despite thorough investigations, the specific testing procedures for evaluating the friction and wear properties of the alloy and/or biomedical component are still uncertain. The majority of researchers have selected test methods and parameters based on previous studies or their own knowledge, but there is a scarcity of studies that incorporate limb-specific tribological tests that consider the distinct kinematic and biological structure of human limbs. Since advanced microscopy has great potential in this field, a variety of advanced characterization techniques have been used to reveal the relationship between microstructural and tribological properties. Many coating-based strategies have been developed using anodizing, PEO, VD, PVD, nitriding, thermal spray, sol-gel, and laser cladding, however; composition and processing parameters are crucial to improving tribological behaviour. Reinforcing component type, amount, and distribution has dominated Ti matrix composite research. Ti grade 2 and Ti6Al4V alloy has been the most widely used matrix, while various reinforcements, including TiC, Al2O3, TiB, hydroxyapatite, Si3N4, NbC, ZrO2 have been incorporated to enhance tribological performance of Ti matrix. Mechanical surface treatments improve biomedical Ti alloys' tribological performance, which is advantageous due to their ease of application. The implementation of machine learning methods, such as artificial neural networks, regression, and fuzzy logic, is anticipated to make a substantial contribution to the field due to their ability to provide cost-effective and accurate results. The microstructural and surface features of biomedical Ti alloys directly affect their tribological properties, so image processing strategies using deep learning can help researchers optimize these properties for optimal performance. [ABSTRACT FROM AUTHOR]

Percutaneous implants osseointegrated into the residuum of a person with limb amputation need to provide mechanical stability and protection against infections. Although significant progress has been made in the biointegration of percutaneous implants, the problem of forming a reliable natural barrier at the level of the surface of the implant and the skin and bone tissues remains unresolved. The use of a microporous implant structure incorporated into the Skin and Bone Integrated Pylon (SBIP) should address the issue by allowing soft and bone tissues to grow directly into the implant structure itself, which, in turn, should form a reliable barrier to infections and support strong osseointegration. To evaluate biological interactions between dermal fibroblasts and MC3T3-E1 osteoblasts in vitro, small titanium discs (with varying pore sizes and volume fractions to achieve deep porosity) were fabricated via 3D printing and sintering. The cell viability MTT assay demonstrated low cytotoxicity for cells co-cultured in the pores of the 3D-printed and sintered Ti samples during the 14-day follow-up period. A subsequent Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) analysis of the relative gene expression of biomarkers that are associated with cell adhesion (α2, α5, αV, and β1 integrins) and extracellular matrix components (fibronectin, vitronectin, type I collagen) demonstrated that micropore sizes ranging from 200 to 500 µm of the 3D printed and sintered Ti discs were favorable for dermal fibroblast adhesion. For example, for representative 3D-printed Ti sample S6 at 72 h the values were 4.71 ± 0.08 (α2 integrin), 4.96 ± 0.08 (α5 integrin), 4.71 ± 0.08 (αV integrin), and 1.87 ± 0.12 (β1 integrin). In contrast, Ti discs with pore sizes ranging from 400 to 800 µm demonstrated the best results (in terms of marker expression related to osteogenic differentiation, including osteopontin, osteonectin, osteocalcin, TGF-β1, and SMAD4) for MC3T3-E1 cells. For example, for the representative 3D sample S4 on day 14, the marker levels were 11.19 ± 0.77 (osteopontin), 7.15 ± 0.29 (osteonectin), and 6.08 ± 0.12 (osteocalcin), while for sintered samples the levels of markers constituted 5.85 ± 0.4 (osteopontin), 4.45 ± 0.36 (osteonectin), and 4.46 ± 0.3 (osteocalcin). In conclusion, the data obtained show the high biointegrative properties of porous titanium structures, while the ability to implement several pore options in one structure using 3D printing makes it possible to create personalized implants for the best one-time integration with both skin and bone tissues. [ABSTRACT FROM AUTHOR]

To explore the influencing factors of surface topography and roughness in ultrasonic elliptical vibration cutting, this study proposed a new prediction model based on the formation mechanism of ultrasonic elliptical vibration cutting surface topography. Applying mathematical transformation ideas and discretization processing, the model considers linear velocity, rear face extrusion, and material rebound and utilizes MATLAB to carry out a simulation analysis of the surface topography. It also verifies the validity and accuracy of the model through experiments. The effects of cutting mode, velocity ratio, feed amount, and tool radius on the surface morphology of ultrasonic elliptical vibration cutting were analyzed using the proposed model. Results show that under the condition of Km < -tanα, the rear face extrusion and material rebound will have a specific impact on the 2-D residual height. In particular, the error between the theoretical roughness of the model and the actual roughness is 20.85%, which can provide some theoretical basis for the selection of machining parameters. [ABSTRACT FROM AUTHOR]

To solve the technical problems of poor strength–plasticity–toughness matching of titanium alloy welded joints, the optimized multi-stranded wires are used as the filler metal for narrow gap laser welding of TC4 titanium, and the welded joints obtained using high-temperature annealing were heat-treated at 850 °C holding 2 h. The macrostructure, microstructure and texture of both welded joints were compared by employing an optical microscope, scanning electron microscope and transmission electron microscope, and the tensile and impact properties were also evaluated. The results show that after heat treatment of the welded zone acicular α' martensite decomposition into lamellar α-phase + β-phase, the welded joint microhardness distribution tends to be smooth, the average tensile strength of the welded joints is 902 MPa, elongation is 14.5%, about 4.1% lower than the as-welded of the welded joints tensile strength, but elongation increased 3.5%, and room-temperature impact energy is 18.5 J, increased by about 54% than the as-welded impact energy, achieving a reasonable match of strength–plasticity–toughness of titanium alloy welded joints. [ABSTRACT FROM AUTHOR]

Titanium alloys have been widely used in marine engineering fields. However, because of high biocompatibility, they are vulnerable to biofouling. In this work, based on the micro‐arc oxidation technology and spontaneous galvanic replacement reaction, a temperature‐responsive low‐toxic smart coating consisting of liquid metal particles is designed to control the release of Ga3+, Cu2+, and Cu1+ ions in different temperatures. This technology can ensure the full release of active ingredients within the target temperature range, intelligently maintaining the excellent anti‐biofouling performance, while saving active ingredients. After being immersed in culture media with Sulfate‐Reducing Bacteria (SRB) for 14 days at 10, 20, and 30 °C, at the optimal activity temperature of 30 °C for SRB, the best sample releases the highest amounts of Ga3+, Cu2+, and Cu1+ ions, demonstrating a 99.9% bactericidal rate. When the temperature decreases to 10 °C, the activity level of SRB is very low, and the smart coating can also reduce the released ions correspondingly, still with a 97.3% bactericidal rate. The remarkable anti‐biofouling performance is attributed to the physical damage and lethal ions interaction. Furthermore, the best sample exhibits good corrosion resistance. This work presents a design route for smart anti‐biofouling coatings for temperature‐responsive. [ABSTRACT FROM AUTHOR]

To improve the biological fouling and corrosion resistance of Ti6Al4V (TC4) in marine environments, copper-containing titanium dioxide (TiO 2 (Cu)) films were prepared by magnetron sputtering TiO 2 (Cu) powder targets. The morphologies of the films showed that they became rough and coarse from 1.6 nm of the TiO 2 film to approximately 9 nm of the TiO 2 (Cu) films, which might be owing to the increase in the deposition rates from 1.33 to 2.08 nm/min. No diffraction orientations of the TiO 2 and Cu phases were found compared to those of the TiO 2 (Cu) powder. Ti, O, and Cu were detected using X-ray photoelectron spectroscopy to confirm the composition of the films. The ratio of Cu2+ increased as the Cu content of the films increased, whereas that of Cu/Cu + scarcely changed. The TiO 2 and TiO 2 (Cu) films exhibited photocatalytic effects and their photocatalytic intensities decreased as the Cu content increased. Hydrophobicity was enhanced by the addition of Cu to the film. The antibiological fouling effect of the TiO 2 (Cu) films remained unchanged as the Cu/Ti ratio varied. Compared with those of TC4, the corrosion current densities of the TiO 2 (Cu) films decreased by one order of magnitude and the corrosion potentials increased by 350 mV in artificial seawater, indicating that the corrosion resistance of TiO 2 (Cu)/TC4 was improved. Importantly, Cu was in abundance in the films for both antibiological and corrosion resistance functions owing to the saturated ratio of Cu/Cu+ irrespective of the Cu/Ti ratio in the films. [ABSTRACT FROM AUTHOR]

Compression tests at room temperature were carried out in order to investigate the influences of hydrogen and compression speed on the room-temperature deformation behavior of TC21 titanium alloy. Microstructure evolution, dislocation density and fracture mechanism during the compression process were studied. The results show that hydrogen and compression speed affect significantly the room-temperature deformation behavior of TC21 alloy. The ultimate compression of TC21-0.8H alloy increases significantly with the increase of the compression speed, which increases significantly as compared to the as-received TC21 alloy at different compression speeds. The dynamic softening phenomenon occurs in the plastic deformation stage of TC21-0.8H alloy when the compression speed exceeds 50 mm/min, and becomes more obvious with the increase of the compression speed. The dynamic softening is mainly caused by the increase of internal temperature, which is closely related to the hydrogen addition and the compression speed. SIM α′′ transformation from metastable β phase occurs during the deformation process of TC21-0.8H alloy, and is suppressed with the increase of the compression speed. The dislocation density of TC21-0.8H alloy is higher than that of the as-received TC21 alloy at the compression speed of 0.5 mm/min, and lower than that of the as-received TC21 alloy at the compression speeds of 50 mm/min, 200 mm/min and 400 mm/min under different true strains. The fracture mechanism of the as-received TC21 alloy and TC21-0.8H alloy is the shear mode at different compression speeds, which conforms to the Mohr-coulomb criterion. • Plasticity of TC21-0.8H alloy increases by 210.32% at 400 mm/min. • Dynamic softening occurs in the plastic deformation stage of TC21-0.8H alloy. • SIM α′′ transformation is suppressed with the increase of the compression speed. [ABSTRACT FROM AUTHOR]

Cobalt-chromium-molybdenum (CoCrMo) and titanium alloys have been used for orthopaedic implants for decades. However, recent evidence has shown that inflammatory cell-induced corrosion (ICIC) can damage these metal alloys. This study aimed to investigate the mechanisms of ICIC by coculturing macrophages with lymphocytes. We hypothesized that macrophages would be able to alter the surface oxide layer of CoCrMo and titanium alloy (Ti6Al4V) disks, with greater oxide layer damage occurring in groups with a coculture compared to a macrophage monoculture and in groups with inflammatory activators compared to nonactivated groups. Murine macrophages were cultured on American Society for Testing and Materials F1537 CoCrMo and F136 Ti6Al4V disks for 30 days and activated with interferon gamma and lipopolysaccharide. Interferon gamma and lipopolysaccharide were added to the culture medium to simulate local inflammation. Macrophages were either cultured alone or in a coculture with T helper lymphocytes. After the 30-day experiment, scanning electron microscopy was used to examine the disk surfaces, and oxide levels were found using energy dispersive x-ray spectroscopy. Pitting features consistent with previous reports of ICIC were found on disks cultured with cells. Both CoCrMo and Ti6Al4V disks had significantly lower oxide levels in all groups with cells compared to control groups with no cells (P <.01). Additionally, CoCrMo disks had significantly lower oxide levels when cultured with activated macrophages and lymphocytes compared to nonactivated macrophages alone (P <.001), activated macrophages alone (P <.01), and nonactivated macrophages and lymphocytes (P <.05). No differences in the oxide levels were found among the Ti6Al4V groups. This study demonstrates the ability of macrophages to alter the surface chemistry of commonly used orthopaedic alloys. We found that the addition of lymphocytes and a simulated local inflammatory response may contribute to the ICIC of CoCrMo implants. [ABSTRACT FROM AUTHOR]

To improve the cutting performance when cutting hard alloys and achieve reasonable optimization of micro-texture parameters, this paper proposes a sinusoidal micro-textured tool, with four parameters set as micro-textured spacing, period, width, and amplitude. Establish threedimensional models of non-micro-textured and micro-textured milling tools and simulate the milling process using finite element simulation. Study the effects of milling force and milling temperature on tool performance. Prepare micro-textured milling tools for orthogonal experiments, analyse the effects of milling force and the surface roughness of a titanium alloy workpiece, and study the impact of different micro-textured parameters on milling tool performance. Obtain the parameters that have the greatest impact on milling tool performance, and then use genetic algorithm to optimize three sets of parameter combinations. Use the optimized parameters to prepare milling tools for comparative experiments, and then determine the optimal parameter combination. The research results indicate that micro-textured tools can effectively improve the milling performance of the tool, and the spacing between sinusoidal micro-textures has the greatest effect on improving the milling performance of the tool. When the period of sinusoidal micro-texture is 2.87 and the amplitude is 25.13 μm, width is 79.89 μm, and spacing is 134.54 μm, the milling performance of the tool is optimal. [ABSTRACT FROM AUTHOR]

Experimental research and finite element analysis were carried out to study the phenomenon of axial shortening and buckling instability of carbon fiber fully wound composite gas cylinders with titanium alloy thin-wall liners after hydraulic test. The results show that, after self-tightening and unloading, the area near the polar hole of the head will be concave axially, the area near the equator of the head will expand radially, and the whole head will become shorter axially. The axial shortening of the head will be 6.15 mm and 6.363 mm, respectively, and the error of the finite element calculation will be 3.46%. The finite element simulation results are in good agreement with the experimental results. Finally, the multi-pole hole method was used to optimize the thickness distribution of the fiber layer of the head, and the extreme thickness of the head was reduced by 32.6%, and the transition was made smoother. After the optimization, the gas cylinder will be slightly extended along the axis, with an average elongation of 0.6 mm. By CT and endoscope detections, no buckling instability would appear in the liner, which means an effective solution of the problems of axial shortening and liner buckling after hydraulic tests. [ABSTRACT FROM AUTHOR]

The paper focuses on plasma cutting of AA5056 and AA2024 aluminum alloy sheets. It is shown that at the minimum thicknesses, the upper edge of the sheet tends to undercut when using reverse polarity. This phenomenon considerably diminishes when using the best cutting conditions. In the case of the AA2024 alloy, most of the material remains in the cutting zone, adhering to the surface and forming a substantial zone of melting or beading. The AA2024 alloy demonstrates a greater oxidation and hardening of the cutting surface. Degraded material layers and surface roughness reduce when using the best cutting conditions. The upper edge of both alloys is more homogeneous and exhibits less roughness than the lower edge. This is attributed to a more complex displacement of the metal relative to the lower edge undercut. [ABSTRACT FROM AUTHOR]

Titanium (Ti) and Ti alloys are the most suitable metallic materials owing to excellent biocompatibility, corrosion resistance and specific strength for many biomedical applications. Selecting best Ti alloy is very important and practical material selection problem. Although many multi-attribute decision-making (MADM) methods are applicable, they may generate considerable differences in the results. However, it is no clarify which is better MADM. It is desirable to determine integrated result by integrating the results obtained from the individual MADMs. We proposed a new integrated MADM methodology based on integrated comprehensive evaluation index (ICEI) of candidates: ICEI-MADM. The ICEIs are the preference-weighted averages of comprehensive evaluation indices (CEIs) of candidates obtained from individual MADMs, and the preference-weights are normalized average correlation coefficients between rankings from the individual MADMs. The methodology can determine not only the integrated evaluation ranks of the candidates but also their integrated evaluation values in full consideration of the preference-weights of the individual MADMs, while the previous methods can determine only the integrated evaluation ranks without considering the preference-weights. We applied it to evaluate the comprehensive performance of 22 biomedical Ti alloys. As the result, Ti-12Mo-6Zr-2Fe (annealed) was the best Ti alloy for implant, the next was Ti-15Mo-5Zr-3Al (aged), and the Cp Ti with different grades were the worst ones. Also, the β type Ti alloys had the best performance, the α + β type Ti alloys had the moderate performance, and the α type Ti alloys had the worst performance. The methodology could be widely applied to not only biomedical Ti alloy selection but also other biomedical material selection and many MADM problems arising in practice. [ABSTRACT FROM AUTHOR]

In the paper, experimental and numerical results of the wear of a molybdenum disulfide coated on a titanium alloy disk are reported. The coating is in contact with a sapphire ball. The experiments are conducted for ambient temperatures varying from 20 to 350 ∘ C. The results indicate that the wear profile becomes increasingly pronounced at the growth of the temperature up to 350 ∘ C. A numerical model is proposed to describe the results of the experiment. The central assumption is the thermal steady state forming in the interface area. The resulting stress field serves as input for the simulation of wear. A good agreement can be observed between the experimental findings and the FE calculations. [ABSTRACT FROM AUTHOR]

Ti-6Al-4V titanium alloy is known as one of the most difficult metallic materials to machine, and the machined surface residual stress distribution significantly affects properties such as static strength, fatigue strength, corrosion resistance, etc. This study utilized finite element software Abaqus 2020 to simulate the two-step cutting process of titanium alloy, incorporating stages of cooling, unloading, and de-constraining of the workpiece. The chip morphology and cutting force obtained from orthogonal cutting tests were used to validate the finite element model. Results from the orthogonal cutting simulations revealed that with increasing cutting speed and the tool rake angle, the residual stress undergoes a transition from compressive to tensile stress. To achieve greater residual compressive stress during machining, it is advisable to opt for a negative rake angle coupled with a lower cutting speed. Additionally, in two-step machining of titanium alloy, the initial cutting step exerts a profound influence on the subsequent cutting step, thereby shortening the evolution time of the Mises stress, equivalent plastic strain, and stiffness damage equivalent in the subsequent cutting step. These results contribute to optimizing titanium alloy machining processes by providing insights into controlling residual stress, ultimately enhancing product quality and performance of structural part of titanium alloy. [ABSTRACT FROM AUTHOR]

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Copyright of Iron Steel Vanadium Titanium is the property of Iron Steel Vanadium Titanium Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)