Search

This paper describes development of multi-layer deposition of Ti6Al4V added with 5 at% of Cr, 5 at% of Ni, and 2.5 at% of each Cr and Ni by μ-plasma powder arc additive manufacturing process. It presents findings on their microstructure, porosity, evolution of phases, microhardness, tensile strength, ductility, fracture morphology, fracture toughness, and abrasion resistance. Phase evolution found that α/α'-Ti and β-Ti phases are formed in all the alloys, intermetallic phase Cr 2 Ti evolved in Ti6Al4V5Cr and Ti6Al4V2.5Cr2.5Ni alloys whereas intermetallic phase Ti 2 Ni is formed in Ti6Al4V5Ni alloy. Their microstructure revealed that addition of chromium and nickel refined grains of their α-Ti and β-Ti phases. Elemental composition of the evolved phases found that at% of chromium, nickel, and vanadium in β-Ti phase is more than the α-Ti phase of the developed alloys. It enhanced their ultimate tensile and yield strength, and microhardness but reduced ductility. It changed the fracture mode from ductile to a combination of ductile and brittle mode possessing large size dimples, micropores, and cleavage facets. It is due to solid solution strengthening, evolution of intermetallic phases Cr 2 Ti and Ti 2 Ni, and grain refinement of β-Ti and α-Ti phases. Enhanced microhardness and presence of intermetallic phases improved fracture toughness and abrasion resistance of the developed alloys thus imparting them higher resistance to propagation of cracks and abrasive wear. [Display omitted] • Addition of Cr and Ni to Ti6Al4V alloy increased yield and ultimate tensile strength but reduced ductility. • The additional elements increased fracture toughness, microhardness, abrasion resistance. • The additional elements changed fracture mode to ductile and brittle with micropores and cleavage facets. • The additional elements refined grains of α-Ti and β-Ti phases. • β-Ti phase of Ti6Al4VxCryNi alloy has more at% of Cr, Ni and V than their α-Ti phase. [ABSTRACT FROM AUTHOR]

The aerospace industry has made extensive use of titanium alloy material due to its exceptional qualities, which include high strength, low weight, and resistance to corrosion. However, these qualities also pose challenges for the material's processing. This article examined the coated end mills for Ti6Al4V milling. First, an analysis was conducted on the solubility of Ti and Si elements. It was discovered that W and Co elements were far more soluble in Ti than Si and Zr elements, which could effectively stop element diffusion. Next, the base's composition was planned. It was discovered that when the amount of Al increased, the base's surface roughness increased, while its hardness and elastic modulus decreased. The binding force between the substrate and the base was greater at a 50:50 Ti:Al ratio. The H3/E2 was about 0.23 and the surface roughness was about 0.15 μm. TiSiN and TiSiN/ZrN functional layer properties were also examined. When Zr was added to TiSiN/ZrN coating, it improved the coating's hardness and elastic modulus, increased density, and decreased surface roughness and friction coefficient when compared to TiSiN coating. There was an increase in hardness by 8.09% and an increase in elastic modulus by 9.65%. The average coefficient of friction decreased from 0.315 to 0.299. Lastly, an analysis of the initial and intermediate tool wear was done using the Ti6Al4V milling experiment. It was discovered that adding Zr element could successfully extend the tool's cutting life by preventing adhesive wear. [ABSTRACT FROM AUTHOR]

Titanium alloys, particularly Ti6Al4V, are widely used in biomedical applications due to their excellent mechanical properties and inherent biocompatibility. However, enhancing their surface characteristics, such as biocompatibility and corrosion resistance, remains a key challenge for their long-term use in medical implants. In this study, we investigate the effects of rhenium–carbon coatings deposited on Ti6Al4V substrates via magnetron sputtering, incorporating a molybdenum anchoring layer. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) analyses confirmed the formation of rhenium carbides, elemental rhenium, and rhenium oxides within the coatings. Despite these successful depositions, scanning electron microscopy (SEM) revealed significant delamination and poor adhesion of the coatings to the Ti6Al4V substrates. Corrosion resistance, evaluated through potentiodynamic polarization tests, showed an increase in corrosion current densities and more negative corrosion potentials, indicating a detrimental effect on the substrate's corrosion resistance. Biocompatibility assessments using PK15 cells demonstrated a marked decrease in cell viability and metabolic activity, particularly in samples with higher surface roughness. These findings underscore the critical need for the optimization of surface preparation and deposition processes to improve both the adhesion and biocompatibility of rhenium–carbon coatings on Ti6Al4V substrates. Future research should aim to refine coating technique to enhance adhesion, explore the mechanisms of cytotoxicity related to surface roughness, and expand biocompatibility studies across different cell lines and biological environments. [ABSTRACT FROM AUTHOR]

Titanium alloys are vital in aerospace engineering due to their exceptional properties. However, the undesired formation of serrated chips during conventional machining poses challenges. Laser-assisted machining (LAM) offers a solution by improving chip morphology, yet optimizing LAM conditions is complex due to the multitude of process parameters involved. This research presents a novel 2D fully coupled thermo-mechanical finite element-based computational model for LAM of Ti6Al4V to effectively predict chip morphology and cutting forces. The model employs fracture mechanics principles to accurately simulate chip serrations, treating chip separation from the workpiece as mode-I failure and chip serrations as mode-II failure. The incorporation of laser heating physics employs the VDFLUX subroutine. Validation against experiments underscores the model's accuracy in predicting cutting forces and characterizing diverse chip morphology under varying process conditions. Notably, the model identifies specific transition points from serrated to continuous chips, such as at 1000 W laser power, 20 mm laser-tool gap, and 3 mm laser spot size for a 90 m/min cutting speed. Similar transitions are observed at 800 W laser power for a 60 m/min cutting speed and a 0.2 mm/rev feed rate. Furthermore, the study comprehensively analyzes cutting forces, providing valuable insights into the LAM process. The developed computational model serves as a valuable tool for optimizing laser parameters to enhance chip morphology and improve the machinability of titanium alloys using LAM. [ABSTRACT FROM AUTHOR]

Over the past two decades, additive manufacturing (AM) has gained attention for its numerous benefits. Despite the growing interest in AM processes for as build Ti6Al4V alloys, there is a lack of comprehensive benchmark research on their impacts. This study addresses this gap by conducting a thorough standard comparison encompassing microstructure, cutting speed, chip analysis, surface roughness, and hardness. Additionally, a conventionally processed Ti6Al4V (grade 23) alloy is a reference for thorough comparison. The research outcomes contribute to a better understanding of AM techniques' implications on building selective laser melted (SLM) Ti6Al4V alloys. Specifically, SLM Ti6Al4V grade 23's investigated material, demonstrates lower cutting forces. This observation is attributed to inherent characteristics, including porosity and the presence of unmelted particles resulting from the SLM process. Particularly, remarkable is the substantially higher hardness observed in SLM Ti6Al4V compared to its conventionally processed counterpart. This insight not only underscores the distinctive attributes of the material but also provides valuable knowledge for optimizing the application of AM Ti6Al4V alloy. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are widely used as implant materials due to their exceptional biocompatibility, light weight, good mechanical properties and high corrosion resistance. Despite remarkable corrosion resistance of titanium alloys, loosening of implants occurs after long-term use due to metallic ions produced during corrosion. This work focuses on corrosion behavior of Ti-6Al-4 V samples fabricated by the laser-powder bed fusion (L-PBF) process and also after heat treatment at 800 °C for 1.5 h and subsequent cooling in furnace. While there was martensitic (α′) phase in the as-built condition, there was dual phase microstructure of α + β phase after heat treatment. Corrosion testing was carried out in Ringer's solution. Electrochemical impedance spectroscopy (EIS) revealed that after heat treatment, the charge-transfer resistance increased from 98096 to 310130 Ω.cm2, due to increase in the oxide layer thickness. The Tafel plot showed a noticeable reduction in corrosion of the heat-treated samples. It was observed by x-ray photoelectron spectroscopy that there was an increase in atomic percentage of Ti, Al, and Oxygen, and decrease in their full width at half maximum, following heat treatment. The ductility of the heat-treated samples under compression was more than double than that of the as-built sample. While the yield strength in compression of heat-treated samples was lower, the compressive strength was higher than that of the as-built sample. Thus, L-PBF process combined with heat treatment can be utilized to fabricate high corrosion resistant Ti-6Al-4 V bioimplants. [ABSTRACT FROM AUTHOR]

We investigated interactions between Ti6Al4V alloys and strontium zirconate (SrZrO3) ceramic to assess its potential as a refractory mold material in investment casting. We developed a robust yet simple procedure to examine both the liquid–solid and solid–solid interactions using pellets in drop casting and diffusion couple methods. Reaction layers were characterized using optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). The results were compared to alumina (Al2O3) which is still a common refractory ceramic for molds in investment casting. Our findings indicate that Ti6Al4V surfaces in contact with SrZrO3 had no apparent changes in surface chemistry nor microstructure. On the other hand, Ti6Al4V surfaces in contact with Al2O3 developed γ-TiAl and α2-Ti3Al intermetallics with thicknesses of ~ 100 μm in diffusion couples and ~ 10 μm in drop-casting experiments. Nanoindentation results showed that the surface of Ti6Al4V in contact with Al2O3 was significantly harder compared to SrZrO3, confirming our conclusion. Given the time and costs associated with mechanical and chemical removal of reaction layers on Ti6Al4V castings, SrZrO3 can be a better choice for a mold material in the investment casting of titanium alloys. [ABSTRACT FROM AUTHOR]

Machining of titanium alloys using hybrid cutting techniques is acquiring importance now-a-days due to the benefits of integrating two or more processes. This study explores such a novel in-house developed hybrid cutting technique, which is a combination of ultrasonic assistance and vortex tube based spot cooling with CO2 gas as coolant for machining Ti6Al4V alloy. CFD aided finite element model was developed and experimentally validated for this novel technique termed spot cooled vibration assisted turning (SCVAT). Parametric study of cooling (nozzle inclination, nozzle tool distance, nozzle diameter, coolant pressure and cold fraction), vibration (amplitude) and machining parameters was carried out in order to identify the role of each parameter on cutting force and cutting temperature. The parametric study showed that flow variables (cold fraction and coolant pressure) are more significant than nozzle variables in influencing cutting force and cutting temperature. SCVAT reduced cutting temperature by 21.66% and 3.45%, respectively, than VAT and spot cooling alone. However, cutting force reduced by 7.65% compared to spot cooling and increased by 11.78% compared to VAT. Overall observations from the CFD aided Finite element model revealed superior performance of SCVAT than its individual counterparts. [ABSTRACT FROM AUTHOR]

This study investigates the microstructural effects of process parameters on Ti6Al4V alloy produced via powder bed fusion (PBF) using laser beam melting (LB/M) technology. The research focuses on how variations in laser power, exposure velocity, and hatching distance influence the final material's porosity, microhardness, and microstructure. To better understand the relationships between process parameters, energy density, and porosity, a simple mathematical model was developed. The microstructure of the alloy was analyzed in the YZ plane using a confocal microscope. The study identified optimal parameters—302.5 W laser power, 990 mm/s exposure velocity, and 0.14 mm hatching distance—yielding the lowest porosity index of 0.005%. The material's average hardness was measured at 434 ± 18 HV0.5. These findings offer valuable insights for optimizing printing parameters to produce high-quality Ti6Al4V components using PBF-LB/M technology, shedding light on the critical relationship between process parameters and the resulting microstructure. [ABSTRACT FROM AUTHOR]

Metal Fused Filament Fabrication provides a simple and cost-efficient way to produce dense metal parts with a homogenous microstructure. However, current limitations include the use of hazardous and expensive organic solvents during debinding for flexible filaments the stiffness of filaments made from partly water-soluble binder systems. In this study, the influence of various additives on different partly water-soluble binder systems, with regard to the flexibility and properties of the final parts, was investigated. Furthermore, a method using dynamic mechanical analysis to quantify the flexibility of filaments was introduced and successfully applied. For the first time, it was possible to produce flexible, partly water-soluble filaments with 60 vol.% solid content, which allowed the 3D printing of complex small and large parts with a high level of detail. After sintering, density values of up to 98.9% of theoretical density were achieved, which is significantly higher than those obtained with existing binder systems. [ABSTRACT FROM AUTHOR]

The aeronautical industry relies on high-performance equipment that demands materials with exceptional engineering attributes, such as the Ti6Al4V alloy. However, the complexity of the parts used in these applications presents challenges related to stack-up tolerances during assembly. Therefore, conventional machining processes are not economically viable due to their two-step nature solution (machining and surface treatment) and their inability to achieve the required accuracy level, particularly given the alloy's hard-to-cut nature. In this matter, wire electric discharge machining (WEDM) emerges as an attractive alternative for fabricating complex geometries. This research focuses on evaluating the potential of the WEDM process for machining micro-complex profiles. A comprehensive range of process parameters, including servo voltage (Vs), pulse on time (Ton), pulse off time (Toff), and wire speed (Ws), are studied using a Taguchi-based design of experiments. The results are analyzed through parametric significance analysis, parametric control analysis, surface morphological analysis using scanning electron microscopy, and modified layer analysis. Additionally, both mono-objective and multi-objective process optimization techniques are employed to achieve superior accuracy and speed. The findings indicate that Ton and Ws have the most significant influence on both cutting speed and spark gap, whereas Vs and Toff play a crucial role in determining the accuracy index. In addition, adequate flushing, reduced wire speed (economically viable), and stability of the spark are recommended to attain a lower spark gap and higher accuracy. The confirmatory experiments show that the optimal parametric conditions of Vs = 60 V, Toff = 30 μs, Ton = 8 μs, and Ws = 6 mm/s provide the highest speed of 3.4 mm/min, minimum spark gap of 0.344 mm, and accuracy index of 98.72%. The findings will contribute to enhancing manufacturing efficiency, precision, and cost-effectiveness in the aeronautical industry, meeting the demand for high-quality components with tight tolerances. [ABSTRACT FROM AUTHOR]

An experimental investigation was conducted to evaluate the machinability of a titanium alloy (Ti6Al4V) using copper (Cu), tungsten carbide (WC), and graphite (C) tools. Voltage (V), capacitance (pF), pulse-on time (Ton), and pulse-off time (Toff) were considered as the input machining parameters, whereas the material removal rate (MRR) and tool wear rate (TWR) were considered as the output machining parameters. A Taguchi L 1 6 orthogonal array and gray relational analysis (GRA) were utilized to design and optimize the machining parameters for both responses. Artificial neural network (ANN) analysis was performed to predict the experimental outcomes. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to assess the surface morphology and determine the elemental composition of the machined surface. The results indicated that the optimum machining conditions for the copper tool were 150 V, 1000 pF, 15 μ s (Ton), and 15 μ s (Toff). However, the optimal machining conditions for the WC were 200 V, 100 pF, 25 μ s (Ton), and 10 μ s (Toff), and the optimal conditions for the C were 200 V, 1000 pF, 20 μ s (Ton), and 25 μ s (Toff), respectively. The highest MRR achieved using the WC tool was 9.4510 mg/s, whereas the TWR of the Cu, WC, and C tools were 1.1039 mg/s, 1.0307 mg/s, and 1.2796 mg/s, respectively. The results showed that machining with the graphite tool had a higher TWR than machining with the Cu and WC tools. [ABSTRACT FROM AUTHOR]

Abstract The non-conventional manufacturing technologies are notorious when it comes to productivity and processing time in production-related industries. However, the aerospace and other high-end sectors enjoy another quality matrix of these processes and compromise on the processing time. For instance, the machinability of hard-to-cut materials such as Ti6Al4V aerospace alloy for micro-impressions is challenging and commonly carried out through non-conventional processes. Among these processes, the electric discharge machining (EDM) is famous for machining Ti6Al4V. In the current study, the EDM process is enhanced through modified dielectrics such as kerosene with non-ionic liquids (span 20, 60, and 80) and cryogenically treated tool electrodes (aluminum and graphite), and is compared to the conventional kerosene-based process. A three-phase experimental campaign is deployed to explore parametric effects including modified dielectric conditions (non-ionic liquid type and concentration), tool material, and machine parameter pulse ON:OFF time. A total of 60 experiments (54 modified dielectrics and 6 as baseline) were performed to explore process physics. The statistical analyses show that the unmodified process (kerosene dielectric-based) results in the least favorable results 0.58 mm3/min against cryo-graphite and 1.2 mm3/min against cryo-aluminum electrodes. However, the modified dielectrics outperform and improve process dynamics by altering dielectric conditions through hydrophilic-lipophilic balance. Surface morphological analysis shows significantly shallow craters on the machined surface showing evidence of effective flushing through a modified dielectric (S-20) as compared to a kerosene-based dielectric. A thorough microscopical, statistical, and scanning electron-based analysis is carried out to explain the process and correlate significant improvements.

The natural bone structure exhibits a radial gradient with dense cortical bone externally and porous cancellous bone internally. However, previous studies proposing scaffold designs have predominantly focused on homogeneous porous structures. Moreover, no consensus exists on the optimal structure for gradient porous scaffolds. Our scaffold closely imitated the natural bone structure by incorporating a gradient of pillar diameters. Additionally, we introduced a inverse gradient structure and three uniform diameter pillar structures (400 μm, 600 μm, and 1000 μm) for comparative analysis. Mechanical testing revealed that the compressive strength and elastic modulus of the Ti6Al4V porous scaffolds gradually increased with an increase in pillar diameter. In vitro experiments demonstrated that both the biomimetic gradient and inverse gradient scaffolds promoted osteogenic differentiation, with higher ALP activity (alkaline phosphatase) and osteogenesis-related gene expression compared to the uniform pillar structure scaffolds. The in vivo experiments confirmed these results, highlighting the superior ability of the biomimetic gradient Ti6Al4V porous scaffold to induce new bone formation. Based on our findings, we suggest that the optimal porous structure should have fine-diameter pillars (approximately 400 μm) internally to enhance cell penetration, while coarse-diameter pillars (approximately 800 μm) should be used externally to increase the cell attachment area and enhance mechanical strength. Overall, our study contributes to the field of bone tissue engineering by providing a biomimetic scaffold design that closely imitates the structure of natural bone and promotes osteogenic activity.

To effectively replace diseased and damaged thoracic vertebrae, a series of three-dimensional (3D) printed titanium (Ti) alloy (Ti6Al4V) thoracic fusion cages with varying volume ratio of reinforced scaffolds are designed, and their structure-function relationships are investigated systematically. It is demonstrated that the mechanical strength of fusion cage is gradually enhanced as the scaffold volume increases, which may be attributed to its textural transformation from α phase to β phase. The compressive, shear, and fatigue of fusion cages successfully attain the International Organization for Standardization (ISO 23089), when the scaffold volume ratio exceeds 15%. Furthermore, the biomechanical analyses, including stress distributions and subsidence in flexion, extension, axial rotation, and lateral bending sections of fusion cages, further shed light on their potential clinical applications. This work deeply deciphers the intrinsic connection between biomechanical property and material texture of the thoracic fusion cages, offering valuable insights into their strengthening mechanism, which providing a guidance for the precise design and quick synthesis of other 3D-printed Ti6Al4V implants.

Background/purpose: Additive manufacturing (AM) technology, such as selective laser melting (SLM), has been used to fabricate medical devices of Ti-6wt.% Al-4wt.%V (Ti6Al4V) alloys in dentistry. Strontium (Sr) has been shown to have the potential to treat osteoporosis. The aim of this study was to investigate the physicochemical and biological properties of strontium-containing coatings on selective laser melted Ti6Al4V (SLM-Ti6Al4V) substrate. Materials and methods: The disk of Ti6Al4V was prepared by SLM method. The strontium-containing coatings were prepared by micro-arc oxidation (MAO) in aqueous electrolytes. The surface topography, chemical composition, and phase of strontium-containing MAO (SrMAO) coatings were performed by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), and thin film X-ray diffraction (TF-XRD), respectively. The apatite-forming ability of the MAO coatings was conducted in simulating body fluid (SBF), and the cell proliferation was determined by methylthiazoletetrazolium (MTT) assay. Results: The microstructure of SLM-Ti6Al4V displays acicular α-phase organization. The TF-XRD results indicated that the phase of SrMAO coating was anatase, rutile, and titanium. The calcium, phosphorus, and strontium were detected in the coatings by EDS. Using the SEM, the surface morphology of SrMAO coatings exhibited a uniform 3D porous structure. The SrMAO coatings could induce a bone-like apatite layer after immersion in SBF, and presented significantly higher cell proliferation than untreated specimens in in-vitro experiments. Conclusion: All findings in this study indicate that SrMAO coatings formed on SLM-Ti6Al4V surfaces exhibit a benefit on biological responses and thereby are suitable for biomedical applications.

Ti6Al4V is a widely used alloy due to its excellent mechanical qualities and resistance to corrosion, which make it fit for automotive, aerospace, defense, and biomedical sectors. Due to its high strength and limited heat conductivity, it is difficult to machine. Both the workpiece's and the electrode's conductivity are important factors that impact the electro-discharge machining (EDM) process. In this case, the machining efficiency is also influenced by the electrode selection. As a result, choosing the right electrode and machining parameters is essential to improving EDM performance on the Ti6Al4V alloy. Research on EDM for Ti6Al4V is limited, with little focus on electrode material selection and shape. The impact of EDM settings on MRR, TWR, and surface roughness is complex, and a comprehensive optimization strategy is needed. Copper electrodes are widely used, but further investigation is needed on EDM's effects on Ti6Al4V's surface properties and surface integrity. Addressing these research gaps will improve the understanding and application of EDM for Ti6Al4V, focusing on parameter optimization, surface integrity, and thermal and mechanical effects. By employing copper tools to optimize four crucial EDM process parameters—peak current, duty cycle, discharge current, and pulse-on time—this research aims to increase surface integrity and machining performance. A comprehensive Taguchi experimental design is used to systematically alter the EDM settings. By optimizing parameters using tolerance intervals and response modelling, the recently developed RAMS-RATMI approach improves the dependability of the EDM process and increases machining efficiency. With the optimized EDM settings, there were notable gains in depth of cut enhancement, surface roughness minimization, tool wear rate (TWR) reduction, and material removal rate (MRR). The results of the surface integrity examination showed fewer heat-affected zones, fewer microcracks, and a thinner recast layer. Analysis of variance was used to verify the impact and resilience of the optimized parameters. Superior machining performance, higher surface quality, and increased operational dependability were attained with the Ti6Al4V-optimized EDM process, providing industry practitioners with insightful information and useful recommendations. [ABSTRACT FROM AUTHOR]

Electrical arc machining (EAM) technology offers a competitive and efficient method for removing material from Ti6Al4V alloys. This study investigates the crater morphology and efficient material removal characteristics of EAM. Single-pulse arc discharge experiments were conducted on Ti6Al4V in ambient air with a positive workpiece electrode polarity. The investigation evaluates the impact of discharge current and discharge duration on the diameter, depth, volume of material removal, and the diameter-to-depth ratio of discharge craters. The discharge voltage-current waveform exhibits a delay and a reverse waveform after completion of the discharge. The discharge maintenance voltage throughout the process ranges from 20 to 40 V. The results indicate that an increase in discharge current leads to larger diameters and volumes of material removal. The maximum diameter and material removal volume reach 2430 μm and 0.788 mm3, respectively, significantly surpassing the discharge crater parameters of Ti6Al4V processed by conventional electrical discharge machining. A longer duration could not result in a greater volume of material removal from the craters like discharge current. The derived material removal rate for continuous EAM of Ti6Al4V can reach 11,820 mm3/min at a discharge current of 500 A, a discharge duration of 2 ms and an interval of 2 ms. Higher current and longer duration enable higher energy density and conversion efficiency, resulting in an efficient material removal rate. This study unveils the characteristics of efficient material removal through single-pulse arc machining experiments and the analysis of discharge crater evolution, contributing to a deep understanding of efficient processing efficiency in EAM of Ti6Al4V. [ABSTRACT FROM AUTHOR]

Herein, the detailed corrosion behavior of ultrafast laser‐surface structured Ti6Al4V (using a Ti: Sapphire laser processed under optimum parameters) is carried out in simulated body fluid using electrochemical impedance spectroscopy and correlated with surface characteristics. Laser structuring leads to a topographically modified surface consisting of periodic surface patterns (nanoripples, nanodots) in the presence of a thin oxide layer. Surface processing introduces strain on the surface up to a depth of 150 μm, with the grains aligned along the (101¯0)$\left(\right. 10 \bar{1} 0 \left.\right)$ and (21¯1¯0)$\left(\right. 2 \bar{1} \bar{1} 0 \left.\right)$ planes. The detailed electrochemical impedance spectroscopic studies show the formation of stable passive layers in surface‐structured Ti6Al4V as compared to as‐received Ti6Al4V. [ABSTRACT FROM AUTHOR]

Titanium and its alloys have been recognized as biocompatible materials since decades although these materials can at times show wear, corrosion and thrombosis leading to various health complications. Surface coating has been found to be one of the effective techniques to overcome this issue in-vitro as well as in-vivo. In this paper, thin film coating of zirconia (ZrO 2) on Ti6Al4V is reported using pulsed laser deposition (PLD) technique at elevated substrate temperatures ranging from room temperature to 800 °C (TiZr800). The morphology, composition, wettability and average surface roughness of the samples were analyzed by scanning electron microscope, Raman spectrometer, water contact angle (WCA) and profilometer, respectively. Adhesion between film and substrate was qualified using Elcometer. The tribological studies were performed in ball-on-disc against ZrO 2 counterpart, the electrochemical potential analysis was done in simulated body fluid to replicate body environment and the hemocompatibility test was evaluated on the basis of human whole blood adsorption and distribution of Red Blood Cells (RBCs) on the samples. The results revealed an increase in WCA and film adhesion with increased substrate temperature. At 800 °C, formation of zirconium carbide, a relatively harder material, was observed due to diffusion of substrate carbon into ZrO 2 film, as confirmed by the Raman analysis. In comparison to pristine, TiZr800 sample showed a reduction in wear rate from 3.5 × 10−3 mm3/Nm to 1.1 × 10−3 mm3/Nm indicating improved resistance of the sample against abrasive wear. Further, drop in I corr from 4.96 × 10−7 A/cm2 to 2.75 × 10−7 A/cm2 resulted in a 44 % increase in corrosion protective efficiency of the sample coated at 800 °C. Additionally, a 4.5 fold increase in RBC counts was observed on TiZr800 sample. Therefore, it is inferred that while ZrO 2 coating can improve overall surface properties of Ti–6Al–4V, additional benefits can be obtained by performing PLD at higher substrate temperatures, more so when the temperature is such as to promote formation of ZrC in the coating. [ABSTRACT FROM AUTHOR]

This study investigates the effect of a tantalum addition and lattice structure design on the mechanical and antibacterial properties of Ti-6Al-4V alloys. TPMS lattice structures, such as Diamond, Gyroid, and Primitive, were generated by MSLattice 1.0 software and manufactured using laser powder bed fusion (LPBF). The results indicate that Gyroid and Primitive structures at a 40% density exhibit superior ultimate compressive strength, which closely emulates bone's biomechanical properties. To be precise, adding 8% tantalum (Ta) significantly increases the material's elastic modulus and energy absorption, enhancing the material's suitability for dynamic load-bearing implants. Nevertheless, the Ta treatment reduces bacterial biofilm formation, especially on Gyroid surfaces, suggesting its potential for infection management. Overall, all findings provide critical insights into the development of advanced implant materials, contributing to the fields of additive manufacturing, materials science, and biomedical engineering and paving the way for improved patient outcomes in orthopedic applications. [ABSTRACT FROM AUTHOR]

Prosthetic joint infection represents a problem that worsens the patient's quality of life and produces an economic impact on health systems. We report the anodization of Ti6Al4V coupons obtained by electron beam melting to produce a nanostructured surface. Anodization at 10 V produced TiO2 nanopores with a diameter in the range of 15–20 nm. Thereafter, Ag nanoparticles (AgNPs) were deposited in three different ways to provide antibacterial functionality to the coatings: electrochemically, thermally, and chemically. The electrochemical method did not provide good coverage of AgNPs. At 0.1 V of synthesis potential, cubic, octahedral, and truncated octahedral Ag crystals were obtained. The thermal method provided a good distribution of AgNPs but it damaged the TiO2 nanostructure. The chemical method showed the best distribution of AgNPs over the anodized surface and preserved the anodized nanostructure. For this reason, the chemical method was selected to perform further studies. Ag+ release was monitored in simulated body fluid at 37 °C, reaching 1.86 mg Ag+/L after 42 days. The antibacterial coating showed excellent antibacterial activity and inhibited biofilm formation for Staphylococcus epidermidis RP62A and Staphylococcus aureus V329 strains (lethality > 99.9% for both bacteria and assays). [ABSTRACT FROM AUTHOR]

Ti6Al4V alloy and ZrO2 ceramic have similar application fields and complementary properties. Brazing connections can broaden the application range. When using sealing glass with good air tightness, good electrical insulation, and low connection temperature to connect, the solder is difficult to wet on the metal surface. The traditional method is to oxidize the surface of the alloy at a high temperature, but the film is not uniform and the treatment time is long. In this study, nanosecond laser surface treatment was used as a prewelding pretreatment method to form a micro-nano structure on the surface and perform oxidation treatment. It is particularly important to select the brazing process. After the laser parameters and processing times were determined, the effects of different welding temperatures and holding times on the properties of the joints were compared, and it was found that there were regular changes. Finally, it is concluded that the maximum shear strength is 46 MPa when the welding temperature is 650 °C and the holding time is 30 min. Under this process, the performance of the joint significantly improved under the dual effects of mechanical bonding and metallurgical bonding. This study provides a new idea for the connection of metal and ceramic and has reference value for the selection of the brazing process. [ABSTRACT FROM AUTHOR]

This paper analyzes the tribological behavior of the Ti6Al4V ELI alloy subjected to laser texturization for medical purposes. Laser texturing enables one to observe specific patterns of the material surface at established depths. Microtexturing of the samples was performed using a 355 nm picosecond laser. The influence of the microtexturing process (depending on the process parameters) on the geometric parameters of the proposed laser texturing pattern was evaluated. Selected samples were subjected to tribological testing using the ball-on-plate technique in dry and lubricant-sliding methods (in Ringer solution). The wear properties were evaluated by comparing the coefficient friction, wear volumes, and wear ratio. A scanning electron microscope characterized the morphologies of the wear scar and the wear mechanism. The experimental results show that the surface texturing and the changes in microgrooves can reduce wear. The results indicate, that samples after laser texturing were characterized by 15% higher microhardness, compared to those in the initial state. It was found, a 26% reduction in friction coefficient and 29% in the wear volume compared to the smooth, untextured surface samples under lubricated conditions. The decrease in value of the coefficient friction and wear volume for the samples after the laser texturing process is an effect of synergistic of entrapped wear debris in micro-grooves and increased hardness for samples after laser textured. [ABSTRACT FROM AUTHOR]

Bending deformation is easy to occur under the action of cutting force during machining, due to the weak stiffness of slender beam structural parts of Ti6Al4V. This will lead to the change of the theoretical cutting position relationship between the tool and the workpiece, thus affecting the machining accuracy and quality of the parts. Aiming at the structural characteristics and machining deformation of slender beam parts with weak stiffness of Ti6Al4V, the bending deformation of slender beam structural parts under the action of static force is analyzed by theory of Euler Bernoulli beam and finite element simulation of ABAQUS. The influence of support mode on the overall static stiffness and machining deformation of the beam is discussed. It is concluded that the clamping method of fulcrum assisted support and micro-crystalline wax filling in the machining process of slender beam structural parts of Ti6Al4V cannot only effectively suppress the machining deformation of parts but also solve the problem of machining chatter of parts. The machining accuracy and quality of slender beam structural parts are effectively improved. Slender beam parts with weak stiffness of Ti6Al4V processed according to this clamping concept. The maximum deformation of the part is 0.017 mm, the maximum dimensional deviation is − 0.015 mm, and the surface roughness Ra of the part is less than 0.5 μm. [ABSTRACT FROM AUTHOR]

This study compares the fatigue crack growth (FCG) behavior of Ti6Al4V parts fabricated by laser powder bed melting (LPBF) with four build directions (0°, 30°, 60°, and 90°) and two heat treatments and analyzed the effect of build direction and microstructure on FCG. The results show that the build direction has a significant effect on the FCG rate. Particularly, specimens with 90° build direction have the best FCG resistance while the 0° specimens have the worst. Furthermore, the fragile deposition layer boundary is the main cause of the crack deflection. The microstructure shows that the columnar β grains have less effect on FCG. The increase in resistance to FCG after heat treatment is attributed to the lath‐like α grains consuming the energy for FCG. As compared to needle‐like α′ grains, the lath‐like α grains are more likely to initiate intergranular fracture and secondary cracking, leading to rugged crack tip paths. Highlights: The effect of build direction on FCG of LPBF‐Ti6Al4V part is significant.The heat‐treated lath‐like α grains have better resistance to FCG.Cracks tend to expand in the direction of parallel deposition layers.Secondary cracking is related to build direction and microstructure. [ABSTRACT FROM AUTHOR]

This study comprehensively investigates the micro-milling performance of Ti6Al4V alloy fabricated by laser powder bed fusion (LPBF) in comparison to wrought one. For that purpose, a series of micro-milling tests were performed at several spindle rotational speeds (12 000 and 24 000 rpm), feeds per tooth (2 and 4 µm/tooth), and a constant depth of cut (100 µm) under dry cutting conditions. The micro-milling performance was evaluated in terms of machining forces and temperatures, surface quality, subsurface microstructural characteristics, residual stresses, burr formation, and chip geometry. A 3D micro-milling model including both constitutive and friction models whose coefficients were determined experimentally was developed. The micro-milling model was validated based on the comparison between simulated and measured forces and surface residual stress. The model can simulate quite well both the feed force (F y) and the transverse force (F x) with an error in the range of 6.16–14.53% and 2.51–13.45%, respectively. In most cutting conditions, reasonably well prediction of surface residual stress was achieved in both longitudinal (1.4–29.3%) and transverse (0.7–19.5%) directions. In comparison to the wrought work material, LPBF Ti6Al4V showed higher forces and temperatures, lower surface roughness, higher compressive residual stresses, and lower burr formation. In the case of LPBF Ti6Al4V, subsurface deformation and a higher reduction in microhardness beneath the machined surface were observed after micro-milling. The different micro-milling performances obtained by wrought and LPBF Ti6Al4V alloys were mainly associated with the specific microstructure characteristics of these materials. [Display omitted] ● Micro-milling performances of wrought and LPBF Ti6Al4V alloys. ● Modelling and simulation of 3D micro-milling using CEL approach. ● Accurate prediction of the forces and residual stresses. ● Slightly better surface integrity in machining of LPBF Ti6Al4V in terms of roughness and residual stresses. ● Higher reduction in microhardness generated by machining LPBF Ti6Al4V. [ABSTRACT FROM AUTHOR]

Metal cutting is considered a process of severe plastic deformation (SPD) and often compared to other SPD processes used to develop submicron and nanostructured metallurgical structure in metallics materials. To validate this assumption, a proper determination of the distribution of plastic strain in the machined surface and subsurface is required. This research work deals with the determination of the distribution of the plastic strain in the machined surface and subsurface in orthogonal cutting of Ti-6Al-4V titanium alloy using both experimental and modeling approaches. Plastic strain distribution in the machined subsurface is determined experimentally using in-situ Digital Image Correlation (DIC), while numerical simulation using FEM is used to determine plastic strain distribution up to the machined surface. The experimental plastic strain distribution obtained by DIC and by X-ray diffraction peak broadening is used to validate the predicted plastic strain distribution obtained by FEM simulation. The results show a strong gradient of plastic strain in a thin layer less than 50 µm, with high plastic strain values at the machined surface exceeding 50%. [ABSTRACT FROM AUTHOR]

Titanium alloy Ti6Al4V is of great importance to the aeronautical and medical sectors due to its mechanical properties such as a high strength-to-weight ratio and corrosion resistance. On the downside, machining Ti6Al4V can lead to accelerated tool wear and poor surface finish of the machined part due to its low heat dissipation capacity. Traditionally, oil and water based metalworking fluids (MWFs) have been used to overcome such issues. However, new regulations and eco-friendly manufacturing trends suggest that conventional MWFs should be minimised, as they are hazardous to the environment and workers' health. Additionally, titanium prostheses contaminated with oil can cause severe integration problems on the patient. This article researches the feasibility of replacing conventional emulsions with sustainable liquid carbon dioxide (LCO 2) cooling. For this purpose, an optimisation of the tool geometry (helix angle, clearance angle and cutting edge geometry) for LCO 2 assisted milling of Ti6Al4V was carried out, taking into account parameters such as cutting forces, surface roughness and the microstructure of the machined surface. This research contributes to the development of environmentally friendly and work safe manufacturing processes that meet the challenges of machining Ti6Al4V for aerospace and medical applications. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technology, such as selective laser melting (SLM), has been used to fabricate medical devices of Ti-6wt.% Al-4wt.%V (Ti6Al4V) alloys in dentistry. Strontium (Sr) has been shown to have the potential to treat osteoporosis. The aim of this study was to investigate the physicochemical and biological properties of strontium-containing coatings on selective laser melted Ti6Al4V (SLM-Ti6Al4V) substrate. The disk of Ti6Al4V was prepared by SLM method. The strontium-containing coatings were prepared by micro-arc oxidation (MAO) in aqueous electrolytes. The surface topography, chemical composition, and phase of strontium-containing MAO (SrMAO) coatings were performed by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), and thin film X-ray diffraction (TF-XRD), respectively. The apatite-forming ability of the MAO coatings was conducted in simulating body fluid (SBF), and the cell proliferation was determined by methylthiazoletetrazolium (MTT) assay. The microstructure of SLM-Ti6Al4V displays acicular α-phase organization. The TF-XRD results indicated that the phase of SrMAO coating was anatase, rutile, and titanium. The calcium, phosphorus, and strontium were detected in the coatings by EDS. Using the SEM, the surface morphology of SrMAO coatings exhibited a uniform 3D porous structure. The SrMAO coatings could induce a bone-like apatite layer after immersion in SBF, and presented significantly higher cell proliferation than untreated specimens in in-vitro experiments. All findings in this study indicate that SrMAO coatings formed on SLM-Ti6Al4V surfaces exhibit a benefit on biological responses and thereby are suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

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.)

Titanium-based alloys are a widely applicable engineering material with high strength, low weight, non-magnetic, and corrosion resistance. At the same time, resistance to low temperatures is declared, which offers the material's applicability for, e.g., aircraft or ship technology. Additive technologies are part of the industrial spectrum of material processing, especially the Laser Powder Bed Fusion of Metals method for metal alloys, which creates a layered structure of the resulting body. The topology of the internal structure, in relation to the temperature history of the functional environment, influences thermal expansion and the associated functional characteristics. Knowledge of the thermal expansion of printed strength and non-strength functional components and accessories is essential for future applications, especially in environments with high repeatable temperature changes, such as the aerospace industry. This paper presents the results of testing the expansion, mechanical, microstructural, and mineralogical characteristics of Ti6Al4V over the temperature range of −70 to 60 °C using a combination of instrumental techniques such as X-ray diffraction and nanoindentation. It was found that the topological orientations of the printed samples directly influenced the tested properties, e.g., the coefficient of thermal expansion in the direction perpendicular to the printed layers showed approximately 12% lower value compared to the other directions. Due to the progression of the application of the manufacturing method and its applicability within selected industries, the research provides results in a new area, which is supported by the relevant research. [ABSTRACT FROM AUTHOR]

Ti6Al4V, as an excellent high-temperature alloy, finds widespread application in key components within industries such as aerospace, automotive, and others. However, due to its high hardness and low thermal conductivity, conventional turning of Ti6Al4V often leads to significant cutting forces and elevated cutting temperatures. Consequently, this imposes higher performance requirements on cutting tools. In dry cutting or with a cooling strategy, micro-texture tools exhibit better cutting performance than conventional tools. This paper investigates the performance of the edge margin complex micro-texture tool and its influence on the machined surface during cutting Ti6Al4V. Through experiments and numerical simulations of the Ti6Al4V cutting process, the cutting performance of four different types of tools is studied. Simulation models of different cutting tools are established, and changes in cutting force, thrust force, cutting temperature, and Von Mises Stress are compared. The results indicate that, compared with the round edge tool, the maximum temperature decreases by up to 16.7%, and the maximum Von Mises Stress decreases by up to 69.6% with the edge margin complex rectangular micro-texture cutting tool. Moreover, the occurrences of self-excited vibration with the other three types of tools decrease by 4.3% to 48.6%. These findings contribute to improving surface quality and prolonging the life of cutting tools when cutting Ti6Al4V with the edge margin complex rectangular micro-texture cutting tool. [ABSTRACT FROM AUTHOR]

The mechanical properties of Ti6Al4V and ST316L bone implants make them superior to natural bone, which results in fewer contact points with the bone. Different manufacturing processes, such as selective laser melting (SLM), may result in different mechanical properties between Ti-6Al-4V and ST316L implants. Sustainable development for the composite implants was optimized (SLM) in this study to minimize their compressive strength and Young's modulus. A threedimensional printing process using SLM was optimized based on laser power, hatch distance, laser velocity, and ST316L weight percentage. Composite implants made from titanium alloys and steel alloys were evaluated using response surface methodology (RSM). ST316L composition has been found to influence the mechanical properties of composites in a significant manner, based on the results of parameter optimization. Using Ti6Al4V/ST316L as a biomaterial in knee joint prostheses is possible. [ABSTRACT FROM AUTHOR]

This paper investigates the fatigue behaviour of laser powder bed fusion (LPBF) processed Ti6Al4V samples under three build orientations. The post-heat treatment (PHT-1050 °C) was carried out. The microstructural characterization was performed using optical microscopy, X-ray diffraction SEM and EDS techniques. The tensile test and high cycle fatigue tests were performed. The PHT performed at 1050 °C exhibited Widmanstatten microstructure consisting of a higher volume fraction of elongated β and a small amount of α. PHT samples' ductility was ~ 67%, 40% and 177% higher than the as-printed samples under horizontal, inclined and vertical orientations. Interestingly, the fatigue lives of PHT samples at higher stress levels were higher and nearly isotropic in all three build orientations than the as-printed samples due to enhanced ductility and fewer critical pores. Further strong correlation between PHT samples and ductility was established. Moreover, there was a marginal improvement in fatigue limit due to PHT at 1050 °C compared to as-printed samples. [ABSTRACT FROM AUTHOR]

Copyright of Dicle University Journal of Engineering / Dicle Üniversitesi Mühendislik Dergisi is the property of Dicle Universitesi 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.)

In the present study, the effect of laser intensity on the microstructure, residual stress, microhardness, and corrosion resistance property of laser shock peened Ti6Al4V using an Nd: YAG laser has been investigated. The applied laser intensity varied from 1 to 8 GW/cm2. During the processing, the pulse density was 574 pulses/cm2, and water was used as a confining layer. Due to laser shock peening, there is refinement of microstructure and presence of oxides on the surface. The residual stress on the surface was found to vary from + 130.12 to − 138.16 MPa and varied with process parameters. There is an increase in microhardness which also varied with process parameters. Due to laser surface processing, there is a significant improvement in corrosion resistance. A detailed structure–property correlation has been established. [ABSTRACT FROM AUTHOR]

This study investigated the effects of electro-erosion (EDM) processing parameters on TiN-coated Ti6Al4V alloy by the physical vapour deposition (PVD) technique. Electrode wear rate (TWR), workpiece machining rate (MRR), and surface roughness (Ra) values were determined by including discharge current, pulse time (ton), and two different tool electrodes (E-Cu and CuBe) into the EDM process parameters. Variables affecting the experimental study (ANOVA) were performed depending on the analysis of variance method. For the analysed (ANOVA) TiN-coated Ti6Al4V samples, the most optimal parameters of MRR value were determined using current 12 A, ton 100, and Cu electrodes. For the TWR value, the optimum parameters were examined by using current 6 A, ton 100, and CuBe electrodes. Finally, 12 A current, ton 100, and electrode E-Cu were analysed for the lowest Ra value. The results showed a better result in MRR and Ra with increasing discharge current, while a better result was obtained in TWR with increasing pulse duration and decreasing discharge current. In addition, it was observed that the E-Cu electrode performed better than the CuBe electrode in processing TiN-coated Ti6Al4V. [ABSTRACT FROM AUTHOR]

Incremental sheet forming is a flexible method to produce 3D sculptured sheet metal parts without expensive and dedicated tools. The present work studies the behaviour of sheets with low ductility undergoing forming under warm conditions. The material selected is Ti6Al4 V titanium alloy which is very hard to deform at room temperature. The temperature of around 500 - 700°C, i.e. below the recrystallisation temperature, is provided to the sheet. In this numerical simulation, a predefined temperature of 500°C is provided initially to the sheet in the predefined field using ABAQUS® software to carry out the test runs. With the increase in temperature, the ductility of the material increases, and the sheet becomes easy to form. The analysis is carried out at a temperature range of 500 - 700°C with different process parameters, viz. step depth, wall angle, and constant tool diameter. Von-Mises stresses, forming depth, and thickness distribution at various input process parameters were studied in the present work. The results obtained show that the fracture depth and thickness distribution increase with a decrease in the mesh size and step depth, whereas they decrease with the decrease in the temperature and increase in the wall angle. [ABSTRACT FROM AUTHOR]