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High-entropy alloys possess significant potential for material applications in demanding structural components subjected to extreme conditions. Through experimental investigations, we have validated that the CoCrFeNiAl0.1Ti0.05 high-entropy alloy, which was fabricated using a cold rolling and annealing process, exhibits an excellent balance of strength and ductility at 77 K. Specifically, it demonstrates a yield strength of 575 MPa, a tensile strength of 1145 MPa, and a ductility of 55%. This enhanced performance can be attributed to the altered deformation mechanism at low temperatures, leading to the multiplications of stacking faults and twins. Additionally, the introduction of small quantities of aluminum and titanium results in the formation of precipitated phases within the alloy matrix. The synergistic influence of these two factors contributes to the augmentation of cryogenic plasticity in the alloy. [ABSTRACT FROM AUTHOR]

One of the main limitations to increasing productivity in machining processes is the emergence of self-excited vibrations. In the turning of titanium alloys, due to its mechanical properties, the material presents low machinability and is prone to the appearance of chatter during processing. Therefore, for this purpose, the material is machined using moderate machining parameters, aiming for parts with a better surface finish and avoiding the appearance of chatter. Therefore, this work seeks to evaluate the influence of machining parameters, cutting speed, feed rate, and cutting depth on vibration during the process and on the roughness of the parts. For this, experiments were carried out varying these parameters, and then the influence of each of them was analyzed using the Taguchi method for planning experiments and signal-to-noise for analyzing the variability of the collected data. It was found that the cutting depth and feed have an influence on the vibration during, where the greater the parameter, the greater the RMS of the signal. And the roughness of the parts is influenced by the cutting speed, in which the higher the speed, the lower the roughness of the parts. [ABSTRACT FROM AUTHOR]

In recent years, additive manufacturing (AM) has gained popularity in the aerospace, automobile, and medical industries due to its ability to produce complex profiles with minimal tolerances. Micro-milling is recommended for machining AM-based parts to improve surface quality and form accuracy. Therefore, the machinability of a titanium alloy (Ti6Al4V) manufactured using selective laser melting (SLM) is explored and compared to that of wrought Ti6Al4V in micro-milling. The experimental results reveal the surface topology, chip morphology, burr formation, and tool wear characteristics of both samples. The micro-milling of AM-based Ti6Al4V generates a surface roughness of 19.2 nm, which is 13.9% lower than that of wrought workpieces, and this component exhibits less tool wear. SLM-based Ti6Al4V produces continuous chips, while wrought Ti6Al4V yields relatively short chips. Additionally, SLM-fabricated Ti6Al4V exhibits smaller burrs after micro-milling than wrought Ti6Al4V. Despite the higher hardness of SLM-based Ti6Al4V, it demonstrates better machinability than wrought Ti6Al4V, resulting in better surface quality with lower tool wear levels and shorter burr heights. This study provides valuable insights into future research on postprocessing AM-based titanium parts, especially using micro-milling. [ABSTRACT FROM AUTHOR]

ABSTRACT Background Case Presentation Conclusion Malignant tumors originating in the talus are rare and present significant challenges in reconstruction. Traditional treatments, such as below‐knee amputation or tbiocalcaneal fusion, often result in significant loss of ankle function. After tumor resection, reconstruction of the talus and calcaneus is necessary to preserve ankle function. However, the intricate anatomical structure and unique location of the talus and calcaneus present significant challenges for prosthetic reconstruction.Here, we present the case of an 11‐year‐old adolescent patient diagnosed with Ewing's sarcoma of the talus, accompanied by suspected involvement of the calcaneus. Following a comprehensive evaluation, a 3D‐printed talus‐calcaneus prosthesis, which is composed of a ultrahigh‐molecular weight polyethylene (UHMWPE) part and a titanium alloy part, was designed for talus and calcaneus reconstruction. In addition, a porous structure was designed to promote the integration of bone–prosthesis interface. The lesion was completely resected and the prosthesis was precisely installed. After 12 months follow‐up, patients demonstrated favorable function results with the Musculoskeletal Tumor Society (MSTS) score was 27/30, and the American Orthopedic Foot and Ankle Society (AOFAS) score was 92/100. The range of motion for dorsiflexion, plantarflexion, inversion, and eversion of the right ankle joint was measured as 10° and 35°, 15°, and 10°, respectively. The postoperative radiograph showed a good position of the prosthesis. No narrowed joint space was observed. Tomosynthesis shimadzu metal artifact reduction technology (T‐SMART) revealed that integration between bone and prosthesis was good.In this case, we present a case of 3D‐printed talus‐calcaneal prosthesis reconstructing talus and calcaneus. Favorable postoperative function outcome and good integration of the interface were observed. Therefore, this case provides an alternative therapeutic option for the treatment invasive talus tumor accompanied by suspicious contamination of the calcaneus. Nevertheless, a larger cohort study and with longer follow‐up is needed to evaluate the effectiveness and potential complications of this novel prosthesis. [ABSTRACT FROM AUTHOR]

Titanium alloys can be ignited under extreme conditions including high pressure, high temperature, and high-speed friction. A theoretical description of the ignition conditions for titanium alloys is critical for their safe use in aerospace industries. In this study, a chemical-absorption-controlled ignition model for bulk TC17 alloy in oxygen-enriched atmospheres was developed based on Semenov's thermal ignition theory. The adsorption coefficient, reaction order, and activation energy for the ignition of TC17 alloy were obtained by fitting the model with the experimental critical oxygen pressure and critical ignition temperatures. The fitting results showed that the chemical-absorption-controlled ignition model fitted better with the experimental data compared with the diffusion-controlled ignition model, implying that the ignition process was controlled by chemical absorption rather than oxygen diffusion through the oxidation layer. Moreover, the activation energy for the ignition of TC17 alloy bars was obtained to be 50.01 kJ/mol, which was only less than one-fourth of that of non-isothermal oxidation (231.98 kJ/mol), indicating that the ignition requires much lower activation energy than oxidation. The chemical-absorption-controlled ignition model successfully predicted the ignition temperature of TC17 alloy bars with different diameters with the relative error within 4.41%, demonstrating the validity of the model. [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]

This study investigates the spheroidization of titanium Ti-6Al-4V powder particles using numerical models developed in Abaqus and OpenFOAM. Spherical particles are crucial in powder-based additive manufacturing due to their superior flowability, packing density, and mechanical properties, enhancing printing precision and the quality of final products. While conventional techniques such as gas atomization and plasma spheroidization have been extensively researched, the potential of laser spheroidization remains underexplored. To address this gap, detailed numerical analyses of laser spheroidization were conducted, modeling heat transfer from the laser to powder particles using a transient uncoupled heat transfer method with latent heat considerations, while particle deformation was simulated with a phase-fraction-based interface-capturing approach integrated with Navier-Stokes equations. The results, validated against analytical models, indicate that particles within the 20–80 μm range experience optimal spheroidization within a 0.005-second residence time under laser heating, with particles smaller than 30 μm reaching evaporation temperatures of 5,000°C, while larger particles reshape without evaporating under a typical heat flux of 94 MW/m2 (1.8 kW laser power). This study demonstrates that laser spheroidization of Ti-6Al-4V powder can potentially increase powder yield by 10%, offering higher power density and shorter melting times compared to plasma spheroidization, thus presenting a more efficient alternative for achieving spherical particles of specific sizes. [ABSTRACT FROM AUTHOR]

The corrosion behavior of the TiTaNbZrAg alloys with different amounts of tantalum (0%, 10% and 20%) and with distinct surface topography (smooth and rough) was investigated in phosphate buffer solution (PBS) for long-time immersion (1000 h). By this approach, we expect to bring about new insights into the influence of both the amount of Ta in the alloy composition and the surface topography on the corrosion behavior of the Ti-based alloys. The corrosion resistance was studied by Open Circuit Potential (OCP), Potentiodynamic Polarization (PP), and Electrochemical Impedance Spectroscopy (EIS). From the potentiodynamic investigations, it was observed that all types of samples showed good corrosion resistance (i.e., Rcorr < 10 µm y−1) and may be used successfully for medical applications. However, the samples with smooth surfaces and with a certain amount of Ta (10% and 20%) exhibit the best corrosion performance (Rcorr < 1 µm y−1). As regards the samples with rough surfaces, the results evidenced that they showed lower corrosion resistance (1 < Rcorr < 3 µm y−1), suggesting that the Ta presence does not necessarily hinder the corrosion processes. Actually, the synergetic effect of both the presence of Ta and surface roughness plays an important role in corrosion resistance. [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]

A new method of machining ultrasonic cavitation abrasive flow based on phase control technology was proposed for improving the machining efficiency of the inner wall of TC4 (Ti-6Al-4V) titanium alloy tubes. According to ultrasonic phase control theory and Hertzian contact theory, a model of ultrasonic abrasive material removal rate under phase control technology was established. Using COMSOL Multiphysics 6.1 software, the phase control deflection effect, acoustic field distribution, and the size of the phase control cavitation domain on the inner wall surface were examined at different transducer frequencies and transducer spacings. The results show that the inner wall polishing has the most excellent effect at a transducer frequency of 21 kHz and spacing of 100 mm. In addition, the phased deflection limit was explored under the optimal parameters, and predictive analyses were performed for voltage control under uniform inner wall polishing. Finally, the effect of processing time on polishing was experimented with, and the results showed that the polishing efficiency was highest from 0 to 30 min and stabilized after 60 min. In addition, the change in surface roughness and material removal of the workpiece were analyzed under the control of the voltage applied, and the experimental results corresponded to the voltage prediction analysis results of the simulation, which proved the viability of phase control abrasive flow polishing for the uniformity of material removal of the inner wall of the tube. [ABSTRACT FROM AUTHOR]

A comprehensive study was carried out to investigate the effects of Fe addition (0–0.9 wt.%) on the microstructure evolution and mechanical properties of Ti-6Al-4V alloys. The results indicate that Fe addition has a significant refinement effect on the microstructure of titanium alloys; specifically, 0.9 wt.% Fe addition can lead to a 47.37% decrease in the width of lamellar α. The modulus also decreases by 18.89% with the increase in the Fe content, being 91.40 GPa in Ti-6Al-4V-0.9Fe. And the microhardness and wear resistance are improved due to Fe addition. In addition, the constitutive equation of the Fe content and the elastic compliance coefficient were calculated, which can better describe the relationship between Fe addition and the elastic–plastic properties of titanium alloys. The slip systems' activity during the deformation process was also discussed using the Schmid factor. It shows that Fe addition is beneficial for the activity of prismatic and pyramidal slip systems, especially in the {10 1 ¯ 0} <11 2 ¯ 0>, {10 1 ¯ 1} <11 2 ¯ 3>, and {11 2 ¯ 2} <11 2 ¯ 3> slip systems. [ABSTRACT FROM AUTHOR]

Test artifacts, resembling real machine parts, allow for quantitative evaluation of system performance and provide insight into individual errors, aiding in improvement and standardization of additive manufacturing. The article provides a comprehensive overview of existing test artifacts, categorized based on geometric features and the material used. Various measurement techniques such as stylus profilometry and computed tomography are employed to assess these artifacts. It is also shown that the selective laser melting (SLM) technology and titanium alloys are prevalent in artifact creation. Specific artifact categories include slits, angular aspects, length parameters, variable surfaces, and others, each accompanied by examples from research literature, highlighting diverse artifact designs and their intended applications. The paper critically discusses the main problems with existing geometries. It underscores the importance of user-friendly and unambiguous artifacts for dimensional control, particularly in surface metrology. Furthermore, it anticipates the continued growth of metrological verification in future manufacturing environments, emphasizing the need for precise and reliable measurement results to support decision-making under production conditions. [ABSTRACT FROM AUTHOR]

Low prediction accuracy of natural frequencies of a milling robot is one major obstacle to the avoidance of chatter vibration in low-speed robotic milling. For enhanced accuracy in predicting the natural frequency of mixed robot, a variable stiffness model is proposed featuring the dependency of joint stiffness on the joint variables, rather than the constant joint stiffness in the traditional assumption. By integrating the variable joint stiffness model into a mode-reduced 4DOF model modified for the present study, the new method for predicting the robot natural frequency is then built, analyzed, and verified through simulation and modal tests by both a 3-axis accelerometer and a laser vibrometer on the milling robot under different robot configurations. Comparison of the experimental values from the modal tests against the natural frequencies predicted by the proposed model reveals a predicting error of less than 10%, hence enhanced accuracy of the proposed variable joint stiffness model in a large operational space. Based on the model, milling parameters without structural vibration has been selected, and the quality of the robot milling for titanium alloy has been improved. [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]

The article presents the research on turning the titanium alloy Ti6Al4V with uncoated carbide blades and physically coated with PVD and chemically CVD. By examining the processed surfaces using the contact method, it was found that the chemically applied coating allows one to obtain the best 3D roughness. Using finishing cutting parameters and CVD-coated blades, it is possible to obtain a surface with a roughness of Sq at the level of 0.7 μm and Sz 2 μm. Cutting force tests have shown that applying coatings to the cutting blade increases the total cutting force by approximately 20%. Additionally, on the basis of microscopic observations, it was found that thermal and adhesive wear occurs on the surfaces of coated blades. Tool coatings have no influence on the shape of the chips produced. The grey relational analysis performed showed that the best turning results for the Ti6Al4V alloy are obtained when using an uncoated HX insert with a feed of 0.08 mm/rev and a cutting speed of 70 m/min. The results of this analysis also indicate that the tested blades, which are not recommended for the machining of superalloys, should not be used to turn the Ti6Al4V alloy. [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]

The high yield ratio and low strain hardening ability of titanium alloys significantly limit their engineering applications. In this work, a Ti65Zr30Cu5 (at.%) alloy with nanoscale α laths was additively manufactured and achieved a high yield strength of 1274 MPa and a high strain hardening rate up to 40% of the shear modulus. Results show that universal basal/pyramidal dislocation reactions occur during the tensile deformation process. This triggers high-density sessile 〈c 〉 dislocation junctions, which accumulate and pin other mobile dislocations. Consequently, abundant dislocation walls are induced, leading to a strong hetero-deformation-induced strain hardening effect. [ABSTRACT FROM AUTHOR]

Continuous grain boundary α (CGB-α) usually causes degradation of mechanical properties in titanium alloys. Here, we propose to employ dislocation network in an additively manufactured titanium alloy for GB engineering to suppress CGB-α. A C-bearing titanium alloy was selectively laser melted to produce homogeneously distributed TiC flakes and a dislocation network that links them to GBs. Upon solution treatment, the dislocation network promotes dissolution of intragranular carbides and formation of discrete GB TiC particles. These GB carbides suppress the formation of CGB-α during ageing treatment, which together with the formation of high-density intragranular α leads to excellent strength-ductility synergy. [ABSTRACT FROM AUTHOR]

Titanium alloys are among the widely used biomedical materials due to their biocompatibility and mechanical performance. It is an indisputable fact that the materials used in this area must be antibacterial. Therefore, in this study, the production of antibacterial Titanium alloys using NanoAg particles for use in biomedical applications was investigated. First, Ti-6Al-4 V titanium alloys were produced by the powder metallurgy method, which includes blending, pressing and sintering processes. Nano silver particles were synthesized by a chemical reduction method using silver nitrate and glucose. The resulting solution was subjected to Ag + ions and glucose determinations, pH and turbidity analysis. Nano Ag application was carried out by two different methods; dipping and coating method. The obtained samples were analyzed by scanning electron microscopy (SEM) and optical microscopy. Additionally, as the main purpose of this study, antibacterial analysis against Escherichia Coli and Staphylococcus Aureus was performed by percentage reduction test. While the coating method was seen to be more successful in antibacterial tests, the overall Nano Ag application performance was found to be higher against Escherichia Coli bacteria. Being that the sample containing 5% Nano Ag titanium alloys produced with the coating technique showed 100% killing effect against both Staphylococcus aureus and Escherichia coli. [ABSTRACT FROM AUTHOR]

In this work, a flow field model of WC–12Co powder sprayed by high‐velocity air fuel (HVAF) was established based on the computational fluid dynamics (CFD) method. The macro–micro coupled thermodynamic model of coating multilayer growth process was established based on the birth and death element method. The temperature and velocity of the particles in the combustion flame were applied to the coating growth model, and the transient evolution of the coating temperature and thermal stress was revealed. The results show the temperature and thermal stress of coatings increase with the increasing the number of spraying layers, and their incremental gradient gradually decreases with the increasing the number of deposition layers. The peak temperature of the coating surface reaches 1494 K, and the peak thermal stress of the first coating reaches 2693 MPa. The maximum stress of spraying particles appears at the contact edge of particles. Further preparation of WC coating, through the hardness, friction, and wear, corrosion tests verify that WC–12Co coating can effectively provide the TC18 substrate performance. The microhardness of WC–12Co coating was approximately three times that of TC18 substrate. The average friction coefficient and corrosion rate of the coating are 0.15 and 0.06 mg/cm2/h lower than that of the substrate, respectively. [ABSTRACT FROM AUTHOR]

The microstructural evolution of titanium alloys under high-temperature conditions plays a key role in determining their mechanical properties and hot working behavior. This research presents an advanced method for calibrating β phase reconstruction software using in situ testing on Grade 2 titanium, which achieves accurate reconstruction of the parent β phase microstructure. In addition, unique microstructural observations in the forging of Ti-6246 titanium alloy are highlighted, demonstrating the influence of deformation parameters on the resulting β phase grain structures. Using advanced techniques such as electron backscatter diffraction and Burgers orientation relationship-based software, the research elucidates the behavior of these phases under varying thermal and deformation conditions. In Grade 2 titanium, significant grain growth and phase transformation dynamics were observed upon heating beyond the β-transus temperature during in situ calibration of β phase reconstruction software. The analysis demonstrates the effectiveness of the software in precise reconstructing the parent β phase microstructure based on the orientation of the inherited αs phase. Furthermore, the evaluation of hot forming parameters in Ti-6246 alloy shows the influence of deformation temperature and strain rate on the resulting microstructure. Finite element method analysis coupled with dynamic material modeling elucidates the distribution of temperature, strain rate, and effective strain during forging, which aids in the qualitative assessment of hot workability. Microstructural observations in Ti-6246 alloy forging highlight the presence of elongated colonies of αs phase precipitates, indicative of localized strain intensities and deformation temperatures. In addition, EBSD analysis coupled with β phase reconstruction reveals distinct microstructural features in different regions of the forging. In particular, regions subjected to higher strain rates exhibit elongated β phase grains with pronounced disorientation gradients, suggesting intense deformation. Conversely, optimal forging conditions lead to the appearance of unreinforced axisymmetric β phase grains, indicating dynamic recovery processes. Pole figure analysis further emphasizes the Burgers crystallographic relationship between the αs and β phases, confirming that deformation during forging occurs exclusively within the β phase. These results provide valuable insights into the microstructural evolution in titanium alloys under high-temperature conditions, which are essential for optimizing hot working processes and improving mechanical properties. [ABSTRACT FROM AUTHOR]

Titanium is a highly operational alloy for use in dental implants. Surface inertness of the titanium alloy surfaces reduces osseointegrate, raising concerns about implant loosening. Hydroxyapatite (HA)-rich porous titanium surfaces with moderated surface roughness have better osteoconductivity. This study focused on the surface alteration of Ti6Al4V via hydroxyapatite mixed electric discharge-assisted centerless turning (HA-mixed-EDCLT) to find the optimum surface. The experiments were planned based on a four-factor, three-level Box-Behnken design. HA-powder concentration (Cp), revolutions per minute (RPM), duty factor and impulse current (IP) were the input parameters. The Ra value of machined surfaces ranged from 1.12μm to 1.63μm, which is in the bone growth supportive implants range. The average hardness reached 415.8–962.7HV, where untreated surfaces’ hardness was 340±6HV. Porous, hydrophilic coating with a high Ca, P, and O content deposited on the implant surfaces supports the biocompatibility of implants. Analysis of the elements and compounds shows that the machined surface layer is rich with Ca3(PO4)2 and TiO2,which improves the bioactivity of the alloy. [ABSTRACT FROM AUTHOR]

Metal powder contributes to the environmental burdens of additive manufacturing (AM) substantially. Current life cycle assessments (LCAs) of metal powders present considerable variations of lifecycle environmental inventory due to process divergence, spatial heterogeneity, or temporal fluctuation. Most importantly, the amounts of LCA studies on metal powder are limited and primarily confined to partial material types. To this end, based on the data surveyed from a metal powder supplier, this study conducted an LCA of titanium and nickel alloy produced by electrode-inducted and vacuum-inducted melting gas atomization, respectively. Given that energy consumption dominates the environmental burden of powder production and is influenced by metal materials' physical properties, we proposed a Bayesian stochastic Kriging model to estimate the energy consumption during the gas atomization process. This model considered the inherent uncertainties of training data and adaptively updated the parameters of interest when new environmental data on gas atomization were available. With the predicted energy use information of specific powder, the corresponding lifecycle environmental impacts can be further autonomously estimated in conjunction with the other surveyed powder production stages. Results indicated the environmental impact of titanium alloy powder is slightly higher than that of nickel alloy powder and their lifecycle carbon emissions are around 20 kg CO2 equivalency. The proposed Bayesian stochastic Kriging model showed more accurate predictions of energy consumption compared with conventional Kriging and stochastic Kriging models. This study enables data imputation of energy consumption during gas atomization given the physical properties and producing technique of powder materials. [ABSTRACT FROM AUTHOR]

The micro-machining scale effect makes it challenging to forecast and control the process parameters of the micro-milling process, which makes the micro-flanking-milling of weak-rigidity micro-thin-walled parts prone to deformation. To determine the critical cutting parameters for chip formation in the micro-milling of curved thin-walled parts at the mesoscale, the strain-softening effect of titanium alloy during high-speed milling and the scale effect of mesoscale cutting were comprehensively considered and a finite element prediction model for curved micro-thin-wall micro-milling was established to determine the critical milling parameters for effective material removal. Based on the determined milling parameters, an experimental design of response surface optimization was carried out. Based on the response surface methodology, a data-driven quantitative model with milling process parameters as design variables and deformation amounts as response variables was established to reveal the influence mechanism of multiple milling process parameters on machining accuracy. Based on the process requirements for deformation control in the micro-milling of curved thin-walled structures, dynamic optimization of the milling process parameters was performed using an improved NSGA-III algorithm to obtain non-dominated solutions. A visual ranking and a determination of the unique solution were conducted using the entropy weight–TOPSIS method. Finally, micro-milling validation experiments were carried out using the optimal parameter combination. The optimal solution for the process parameters of the arc-shaped micro-thin-wall micro-milling of titanium alloy established by the institute provides a relevant reference and guidance for mesoscale arc-shaped thin-wall micro-milling. [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]

In this paper, during the heat treatment of TC4 titanium alloy pulsed laser-arc hybrid welded joints, it was found that the degree of V elemental segregation in the β phase of the weld microstructure increased with the slowing down of the cooling rate after holding the weld joint for a certain period above the β phase transition temperature. To reveal the effect of V element segregation in the β phase on the mechanical properties, tensile simulations were carried out using molecular dynamics at different temperatures for different degrees of segregation in the model. The results showed that at the same temperature, when the V elements were segregated in the β phase, the energies of the models were all lower than that of the model with uniform distribution of V elements after relaxation. At the same time, the tensile strengths were all higher than that of the model with a uniform distribution, and the tensile strengths in the x- and y-directions were increased by 17.7% and 8.1%, respectively. In stretching to the maximum stress, the deformation mainly occurred in the β phase, and the deformation mode was a phase transition from BCC to HCP with the formation of nanocrystalline. However, with the increase in temperature and the decrease of the degree of V elemental segregation, the nanocrystalline formed by the deformation gradually decreased, and the grain boundaries also became irregular, which was the main reason for the decrease in the tensile strength. At the same time, after segregation, the start of the BCC phase transition in the tensile process was delayed, which was also beneficial to improving the strength of the model. After exceeding the tensile strength, the deformation was mainly dominated by the slip of dislocations. In addition, with the increase of the degree of V element segregation, the difference in the tensile strength of the model tensile along the parallel and perpendicular grain boundary directions decreased from 0.48 to 0.18 GPa, and the anisotropy of the material was weakened. [ABSTRACT FROM AUTHOR]

Milling shallow-to-deep features in titanium alloy presents machinability challenges when a conventional process is employed. In this context, maskless milling by abrasive waterjet (AWJ) can be a better alternative due to its unique capabilities. Unlike conventional milling, assuming a linear summation of kerf cross-section profiles (CPs) while following the raster jet path, in AWJ milling will not yield an accurate prediction of surface geometry CP due to the nonlinearities involved in material erosion by multiple phenomena (e.g., reflected jets). The unavailability of measurement techniques for gaining insights into this complex AWJ interaction with the target at the milling zone for studying the flow behavior and the associated erosion hindered the development of accurate models for AWJ milling. This necessitates the need for the AWJ milling models that incorporate the abovementioned nonlinearities to yield reliable predictions. Towards this, the present work proposes a novel modelling framework to predict the geometrical characteristics (CP, maximum erosion depth (hmax), top width (WP), and CP area (AP)) of AWJ milled feature in Ti-6Al-4V alloy, considering pocket as a case study under varying jet's overlap percentage (JO%) and jet traverse rate (Vf). To get insights into the changes in the AWJ flow behavior and its interactions upon impinging the nonplanar target (NPT) post-first jet sweep and subsequent jet sweeps, computational fluid dynamics (CFD) simulations are performed. Results show an increasing asymmetric stagnation zone at the NPT relative to the planar target (PT), with the increased JO% and Vf leading to strong tangential flow, causing intense jet reflection and unwanted erosion. These understandings are utilized to mathematically model the unexplained erosion caused by the reflected jets, enabling accurate prediction of CP, hmax, WP, and AP. The proposed model accurately captured the nonlinearities that arose in hmax, WP, and AP with a maximum error of 10%, 11.8%, and 14.8%, respectively. In addition, the validated shapes of the pocket CPs result in an average mean absolute error of 42 µm, which agrees well with experimentally obtained ones. The validation results corroborate the hypothesis that the reflected jets caused upon impinging on the NPT compared to PT significantly contribute to unexplained erosion during milling other than the erosion due to the primary jets. [ABSTRACT FROM AUTHOR]

Peri-implantitis and osseointegration failure present considerable challenges to the prolonged stability of oral implants. To address these issues, there is an escalating demand for a resilient implant surface coating that seamlessly integrates antimicrobial features to combat bacteria-induced peri‑implantitis, and osteogenic properties to promote bone formation. In the present study, a bio-inspired poly(amidoamine) dendrimer (DA-PAMAM-NH 2) is synthesized by utilizing a mussel protein (DA) known for its strong adherence to various materials. Conjugating DA with PAMAM-NH 2 , inherently endowed with antibacterial and osteogenic properties, results in a robust and multifunctional coating. Robust adhesion between DA-PAMAM-NH 2 and the titanium alloy surface is identified using confocal laser scanning microscopy (CLSM) and attenuated total reflectance-infrared (ATR-IR) spectroscopy. Following a four-week immersion of the coated titanium alloy surface in simulated body fluid (SBF), the antimicrobial activity and superior osteogenesis of the DA-PAMAM-NH 2 -coated surface remain stable. In contrast, the bifunctional effects of the PAMAM-NH 2 -coated surface diminish after the same immersion period. In vivo animal experiments validate the enduring antimicrobial and osteogenic properties of DA-PAMAM-NH 2 -coated titanium alloy implants, significantly enhancing the long-term stability of the implants. This innovative coating holds promise for addressing the multifaceted challenges associated with peri‑implantitis and osseointegration failure in titanium-based implants. Prolonged stability of oral implants remains a clinically-significant challenge. Peri-implantitis and osseointegration failure are two important contributors to the poor stability of oral implants. The present study developed a mussel-bioinspired poly(amidoamine) dendrimer (DA-PAMAM-NH 2) for a resilient implant surface coating that seamlessly integrates antimicrobial features to combat bacteria-induced peri‑implantitis, and osteogenic properties to promote bone formation to extend the longevity of oral implants. [Display omitted] [ABSTRACT FROM AUTHOR]

ABSTRACT In order to improve the comprehensive properties of TC4 titanium alloy, micro‐arc oxidation (MAO) coating is prepared on the surface of a TC4 substrate in a basic electrolyte with varying concentrations of Sr(OH)2. The surface morphology, phase composition, element distribution, and corrosion resistance of MAO coatings are analyzed by scanning electron microscopy, X‐ray diffraction, an energy‐dispersive spectrometer, the electrochemical test, and the erosion–corrosion test. The results show that the voltage of the MAO process increases and then decreases; the surface morphology and density of the coatings are greatly improved after doping Sr(OH)2. When the concentration of Sr(OH)2 is 0.6 g L−1, the thickness, hardness, and adhesion strength of the coating reach the maximum values of 37.04 μm, 836.2 HV, and 21.8 N, respectively. At this time, the wear resistance and corrosion resistance are the best, and the friction coefficient and the corrosion rate are the lowest: 0.3352 and 1.04 × 10−10 mm a−1, respectively. [ABSTRACT FROM AUTHOR]

The role of nitrogen in the oxidation of Ti-2W, Ti-10Al-2W (at.%) and Ti6242S was investigated using experiments in air and in Ar-20%O2, and two-stage experiments where the reaction gas was switched from one mixture to the other. When switching from Ar-20%O2 to air, the oxidation rates first increased during a short period, then decreased. This surge of mass gain following the introduction of air was attributed to N pickup, forming a nitride layer and a N-enriched zone in the alloy, below the oxide layer. The subsequent decrease of oxidation rate was attributed to the formation of nitride and/or N-rich zone, which both act as diffusion barriers for oxygen. Switching from air to Ar-20%O2 caused an increase in the oxidation rate of the W-containing alloys, which was attributed to the consumption of this barrier. The gas change had no significant effect on the oxidation rate of Ti6242S, which formed a much thinner nitride layer in air. The faster the nitride layer grows, the faster it is consumed when removing N from the reaction gas, probably because of a higher diffusion rate of N in W-doped TiO2 compared to TiO2 formed on Ti6242S. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to further refine the model, explore the influence of cutting parameters on the machining process, and apply it to practical engineering to improve the efficiency and quality of titanium alloy machining. Design/methodology/approach: This paper establishes a comprehensive thermo-mechanical fully coupled orthogonal cutting model. This paper aims to couple the modified Johnson–Cook constitutive model, damage model and contact model to construct a two-dimensional orthogonal cutting thermo-mechanical coupling model for high-speed cutting of Ti6Al4V. The model considers the evolution of microstructures such as plastic deformation, grain dislocation rearrangement, dynamic recrystallization, as well as stress softening and hardening occurring continuously in Ti6Al4V metal during high-speed cutting. Additionally, the model incorporates friction and contact between the tool and the workpiece. It can be used to predict parameters such as cutting process, cutting force, temperature distribution, stress and strain in titanium alloy machining. The study establishes the model and implements corresponding functions by writing Abaqus VUMAT and VFRICTION subroutines. Findings: The use of different material constitutive models can significantly impact the prediction of the cutting process. Some models may more accurately describe the mechanical behavior of the material, thus providing more reliable prediction results, while other models may exhibit larger deviations. Compared to the Tanh model, the proposed model achieves a maximum improvement of 8.9% in the prediction of cutting force and a maximum improvement of 20.9% in the prediction of chip morphology parameters. Compared to experiments, the proposed model achieves a minimum prediction error of 2.8% for average cutting force and a minimum error of 0.57% for sawtooth parameters. This study provides a comprehensive theoretical foundation and practical guidance for orthogonal cutting of titanium alloys. The model not only helps engineers and researchers better understand various phenomena in the cutting process but also serves as an important reference for optimizing cutting processes. Originality/value: The originality of this research is guaranteed, as it has not been previously published in any journal or publication. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2024-0168/ [ABSTRACT FROM AUTHOR]

Purpose: This study aims to develop a high-performance nanofluid that can be used in titanium alloys machining. Titanium alloys are difficult-to-cut materials and difficult to be lubricated. This study explored the lubrication performance of various carbon nanoparticles in water-based lubricants for titanium alloys. Design/methodology/approach: The lubricating and antiwear properties of the developed cutting fluid were tested by a tribo-tester. The lubricant performance was evaluated through friction coefficient, wear volume and surface quality. The lubrication mechanism was analyzed through surface morphology, wettability and bonding analysis. Findings: The lubricating performance of four kinds of carbon nanoparticles on titanium alloys was tested and the results showed that single-layer graphene had the smallest COF and wear volume. The interaction between nanoparticles and debris was an important factor that influenced the lubrication performance of nanoparticles for titanium alloy. Moreover, the hybrid nanofluid with graphene and spherical graphite in a ratio of 1:2 achieved a balance between lubricating performance and price, making it the optimal choice. Practical implications: The developed lubricant containing carbon nanoparticles that can lubricate titanium alloys effectively has great potential in machining titanium alloy as a high-performance cutting fluid in the future. Originality/value: This paper fulfills an identified need for water-based lubricant for titanium alloys considering the bad tribological properties. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0124/ [ABSTRACT FROM AUTHOR]

The document "NDT INFO" provides a comprehensive overview of various non-destructive testing methods and techniques. It covers topics such as ultrasonic testing, radiography, eddy current testing, thermal and infrared imaging, and acoustic emission. The document also discusses advancements in technology, such as machine learning and artificial intelligence, for defect detection and evaluation in different materials and structures. Additionally, it highlights the importance of continuous improvement in risk management and quality control practices in various industries. [Extracted from the article]

Herein, we fabricated a low-melting-point Zr-16Ti-6Cu-8Ni-6Co eutectic filler based on a Zr-Ti-Cu-Ni filler to achieve effective joining of a Ti6Al4V (TC4) titanium alloy. The temperature at which the brittle intermetallic compound (IMC) layer in the seam completely disappeared was reduced from 920 °C to 900 °C, which broadened the temperature range of the Zr-based filler, brazing the TC4 without a brittle IMC layer. The shear strength of the Zr-16Ti-6Cu-8Ni-6Co brazed joint increased by 113% more than that of the Zr-16Ti-9Cu-11Ni brazed joint at 900 °C. The proportion of β-Ti in the seam of the Zr-16Ti-6Cu-8Ni-6Co brazed joint increased by 21.31% compared with that of the Zr-16Ti-9Cu-11Ni brazed joint. The nano-indentation results show that the elastic modulus of the β-Ti (143 GPa) in the interface is lower than that of the α-Ti (169 GPa) and (Ti,Zr)2(Ni,Cu,Co) (203 GPa). As a result, the β-Ti is subjected to a greater strain under the same stress state compared with the α-Ti and (Ti,Zr)2(Ni,Cu,Co), and the Zr-16Ti-6Cu-8Ni-6Co brazed joint can maintain a higher strength than the Zr-16Ti-9Cu-11Ni brazed joint under a middle–low erosion area of the TC4 base metal. This provides valuable insights into the use of high-strength, fatigue-resistant TC4 brazed joints in engineering applications. [ABSTRACT FROM AUTHOR]

The colonization of microbes and the resulting formation of biofilms on dental implants are significant contributors to peri-implantitis and the failure of these implants. The aim of the research was to analyze the impact of density and depth of laser texturing of the Ti-6Al-7Nb alloy surface on the colonization of selected microorganisms and biofilm formation. Standard strains of Gram-negative and Gram-positive bacteria and yeasts from the American Type Culture Collection—ATCC—were used to demonstrate the ability to form single-species biofilms in vitro. The study evaluated three types of titanium samples with different texture density and depth. The colonization and biofilm formation abilities of the tested microorganisms were assessed. The obtained results were subjected to statistical analysis. Among the analyzed strains, L. rhamnosus showed the highest colonization of the tested surfaces. It was found that there is no relationship between the texture parameters and the number of colony-forming units (CFU/mL) for C. albicans, S. mutans, and L. rhamnosus. For the F. nucleatum strain, it was shown that the number of colony-forming bacteria is related to the texture density. [ABSTRACT FROM AUTHOR]

Titanium and titanium alloys with a medium thickness of 5 to 12 mm are widely used for ocean platforms, military equipment and in other fields because of their light weight, appropriate strength and corrosion resistance. In this study, autogenous laser welding and narrow-gap laser welding processes were researched and compared, and the welding characteristics, weld microstructure and joint strength were analyzed. The results showed that autogenous laser welding had higher efficiency, narrower weld width and higher microstructure uniformity. Autogenous laser welding can achieve the single pass weld penetration at laser keyhole mode. The weld width of narrow-gap laser welded joint was 12.5 mm, which was nearly three times than that of autogenous laser welding. The grain size of autogenous laser welding was obviously smaller and more uniform in depth than that of narrow-gap laser welding. In the weld zone, the coarse columnar α grains grew from the fusion line, while in the heat-affected zone, equiaxed α grains with needle and sawtooth α morphologies were presented. The microhardness of the heat-affected zone was higher than in the weld zone and the base metal due to the denser needle microstructure. The tensile samples all fractured at the base metal, indicating the welded joint strength efficiency was greater than 1. [ABSTRACT FROM AUTHOR]

A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond‐laser (ps‐laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps‐laser‐treated samples. It is determined that the preanodized and laser‐treated sample has 3.5 times larger ECSA than a polished sample, and that the laser‐treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser‐structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps‐laser‐treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples. [ABSTRACT FROM AUTHOR]

Resection of thoracic wall tumors results in significant defects in the chest wall, leading to various complications. In recent years, the use of three-dimensional (3D) printed titanium alloy prostheses in clinical practice has demonstrated enhanced outcomes in chest wall reconstruction surgery. A cohort of seven patients with sternal tumors was identified for this study. Following a helical CT scan, a digital model was generated for the design of the prosthesis. Subsequently, the tumors were then removed together with the affected sternum and ribs. The chest wall was then reconstructed using 3D-printed titanium alloy prosthesis for bone reconstruction, mesh for pleural reconstruction, and flap for soft tissue reconstruction. Patients were monitored for a period of one year post-surgery. In the seven cases examined, the tumors were found in various locations with varying degrees of invasion. Based on the scope of surgical resection and the size of the defect, 3D-printed titanium alloy prosthesis was custom-designed for chest wall reconstruction. Prior to bone reconstruction, pleural reconstruction was achieved with Bard Composix E/X Mesh, while soft tissue repair involved muscle flap and musculocutaneous flap procedures. A one-year follow-up assessment revealed that the utilization of the 3D-printed titanium alloy prosthesis led to secure fixation, favorable histocompatibility, and enhanced lung function. The findings demonstrate that the utilization of 3D printed titanium alloy prostheses represents a significant advancement in the field of chest wall reconstruction and thoracic surgical procedures. [ABSTRACT FROM AUTHOR]

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]

Hollow fan blades made of titanium alloy are widely used in turbofan engines, and the residual stress (RS) inside the blades directly affects the performance of the blades and even the engine. Therefore, it is crucial to measure and study the RS distribution of titanium alloy hollow fan blades. This paper aims to investigate the RS distribution on the cross-section of a wide-chord hollow fan blade made of Ti-6Al-4 V titanium alloy. The multiple-cut contour method is utilized to determine the RS. A theoretical model of the multiple-cut contour method for fan blades is established, and the specimen was cut three times, followed by contour measurement of the cut planes, data processing and elastic finite element analysis. The RS map of the three cut planes is finally presented. The normal RS on three cross-sections of the fan blade is uniformly distributed, ranging from -50 MPa to 50 MPa. The normal RS distribution at different positions for the hollow fan blade can be obtained by the proposed multiple-cut contour method. The findings of this research provide a comprehensive insight into the distribution of RS in wide-chord hollow fan blades made of Ti-6Al-4 V titanium alloy. [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]

Carbon fiber–reinforced polymer (CFRP) and titanium alloy have become the preferred materials for aviation equipment manufacturing due to their excellent mechanical and chemical properties. The high-precision hole-making technology of CFRP/titanium alloy–stacked structure is crucial for ensuring the connection performance of aviation main load-bearing components. However, the significant accumulation of cutting heat during this hole-making process can easily exacerbate tool wear and reduce connecting hole quality. The study developed a low temperature cold wind device based on the Coanda effect and conducted helical/inclined planetary milling hole experiments on CFRP/titanium alloy stacks with/without low temperature cold wind conditions on a rotary worktable for machine tool processing. The effects of cooling device on the machining temperature, milling force, tool wear, and hole quality of helical/inclined planetary milling were analyzed. The research results indicate that the continuous cooling and strong airflow impact of the low temperature cold wind device can significantly reduce the temperature during helical milling and inclined planetary milling, avoiding the serious adhesive wear and cutting edge breakage of the tool, reducing the tearing and burr of the CFRP hole exit and the ablation discoloration of the stacked interface, and lowering the hole wall roughness. As the machining process progresses, the low temperature cold wind device can maintain the cutting temperature at relatively low levels and slow down the wear rate of the milling cutter. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced polymer (CFRP) and titanium alloy (Ti-6Al-4V) have excellent mechanical properties and have been widely used in aviation, aerospace, and other fields. Due to the different characteristics of CFRP/Ti-laminated materials, there are differences in their processing parameters and material removal methods. Cutter wear and hole defects are prone to occur. To study the cutting performance of cutters in laminated materials, this paper adopts the inclined angle milling method to process CFRP/Ti-laminated materials. The cutting performance of flat end milling cutter and circular arc milling cutter was compared and analyzed through designed variable parameter experiments. A study was conducted on the axial force, cutter wear mechanism, hole quality, and micro-morphology of the hole wall of two cutters under the inclined angle milling method. The results show that under different processing parameters, the difference in axial force between the two cutters is small in the carbon fiber layer. However, there is a significant difference in the titanium layer, with the axial force of the circular arc milling cutter being smaller than that of the flat end milling cutter. As the number of holes increases, the wear of the flat end milling cutter is serious, and the cutting edge is broken. The wear area gradually expands from the cutter tip to the surrounding cutting edge. The wear of the circular arc milling cutter is relatively light, and the cutting edge is damaged. As the wear at the arc transition becomes dull, the wear area gradually extends to the surrounding cutting edge. As the cutters wear out, many burrs and tear damage appear at the CFRP exit of the flat end milling cutter. Many high burrs appeared at the exit of Ti-6Al-4V. Comparing the micro-morphology of the hole wall of the two cutters at different fiber cutting angles, the quality of the hole wall of the flat end milling cutter is worse than that of the circular arc milling cutter. Due to the arc transition structure of the circular arc milling cutter, the hole wall has obvious groove scratches, resulting in a decrease in the quality of the Ti-6Al-4V hole wall. In addition, compared with the flat end milling cutter, the surface roughness of the hole of the circular arc milling cutter is better. [ABSTRACT FROM AUTHOR]

The structural features and phase composition are examined in near-surface layers of specimens of Al-Mg, Al-Cu-Mg alloys and commercially pure titanium obtained by plasma cutting using direct current straight polarity (DCSP) and direct current reverse polarity (DCRP). It is found that the flows of molten metal ejected by the gas stream from the cut cavity during cutting form the fusion and heat-affected zones, whose structural morphology, phase composition, and thickness depend on both the selected material and the cutting mode. The fusion zone is thicker in specimens cut using DCRP than in those cut with DCSP. The thickness of the adjacent heat-affected zone is also the largest in the mode that provides a thicker fused layer. Aluminum alloy specimens cut in ambient air are characterized by the presence of oxygen in the near-surface layers. The lowest degree of oxidation is observed in Al-Mg alloy. Oxygen penetrates into the fused layer to a depth of 350–500 μm in Al-Cu-Mg and up to 200–250 μm in Al-Mg alloy. In titanium alloy, the thickness of oxide layers does not exceed 100–150 μm during straight polarity cutting and 200–250 μm during reverse polarity cutting. A thin brittle layer of TiO and TiO2 oxides is formed on the titanium alloy surface. It is shown that the generation of "water mist" around the plasma jet when cutting materials of all types with DCRP leads to a more intensive oxidation of metal, less thermal effect on the material, and reduced roughness of the cut face. [ABSTRACT FROM AUTHOR]

Ti-6Al-4 V is an extensively used and highly versatile titanium alloy. It is renowned for its lightweight-to-strength ratio, excellent biocompatibility, and corrosion resistance. The pursuit of advanced materials with enhanced mechanical strength, and wear resistance has led to the exploration of high entropy alloys (HEA) as particle reinforcements. This study combines Ti-6Al-4 V with AlCoCrFeNi HEA at different weight compositions (0 %, 2 %, 4 %, 6 %, 8 %) to create novel composites with tailored properties. The composites were subjected to density, microhardness, tensile, and pin-on-disc tests to evaluate mechanical and tribological properties. Microstructural analysis revealed that microwave sintering has enhanced densification and resulted in uniform dispersion of HEA particles within the Ti-6Al-4 V matrix. The XRD and EBSD analysis revealed the presence of BCC structure in the composite. 8 wt%-AlCoCrFeNi/Ti-6Al-4 V sample exhibited an impressive 81.66 % increase in microhardness and 21.23 % in yield strength, compared to the base sample. Furthermore, noteworthy reductions of 45 % in wear rate and 40 % in coefficient of friction (COF) when subjected to tribological analysis. The worn surface revealed the presence of oxide layer formation at elevated sliding velocity and distance which resulted in reduced wear rate. [ABSTRACT FROM AUTHOR]

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

Titanium alloy, Ti–6Al–2.2Mo–1.4Cr–0.4Fe–0.3Si (BT3-1), is a two phase α + β alloy developed for applications in rocket engines, gas turbine engines, and aircraft frames for service up to a temperature of 450 °C. The hot workability of this alloy has been studied through isothermal hot compression testing in the temperature and strain rate (ε ˙) range of 800 °C to 1000 °C and 10−3 to 10 s−1, respectively, in a thermomechanical simulator. Processing maps using dynamic material model has been generated and different regions of the map were correlated with microstructural observations. The flow stress data were fitted in Arrhenius strain-compensated model and constitutive equations were developed. Optical microstructures revealed elongated grains, kinking of α phase, flow localisation, and adiabatic shear bands at lower temperatures. Super-plasticity was found to be operative at low temperature of 850 °C and ε ˙ 10−3 s−1, whereas dynamic recrystallization (DRX) was dominating at high temperatures of 950 °C to 1000 °C and ε ˙ of 10−3 s−1. Finite element analysis showed the flow localization in the unstable regions of processing map. Enhanced hot workability was achieved above 950°C in the ε ˙ of 10−2−10−3 s−1 due to initiation of DRX in view of an increase in the β phase fraction. [ABSTRACT FROM AUTHOR]

Fretting wear damage of high-strength titanium fasteners has caused a large number of disastrous accidents. Traditionally, it is believed that both high strength and excellent ductility can reduce fretting wear damage. However, whether strength and ductility are contradictory or not and their appropriate matching strategy under the external applied normal stress (Fw) are still confusing problems. Here, by analyzing the subsurface-microstructure deformation mechanism of several samples containing various α precipitate features, for the first time, we design strategies to improve fretting damage resistance under different matching relation between Fw and the tensile strength of materials (Rm). It is found that when Fw is greater than Rm or Fw is nearly equivalent to Rm, the deformation mechanism mainly manifests as serious grain fragmentation of β and αGB constituents. Homogeneous deformation in large areas only reduces damage to a limited extent. It is crucial to improve the strength to resist cracking and wear, but it is of little significance to improve the ductility. However, when Fw is far less than Rm, coordinated deformation ability reflected by ductility plays a more important role. The deformation mechanism mainly manifests as localized deformation of β and αGB constituents (kinking induced by twinning and spheroidizing). A unique composite structure of nano-grained/lamellar layer and localized deformation transition layer reduces fretting damage by five times compared with a single nano-grained layer. Only when the strength is great enough, improving the plasticity can reduce wear. This study can provide a principle for designing fretting damage resistant alloys. [ABSTRACT FROM AUTHOR]

In this work, the following are investigated: structure, phase composition and mechanical properties under static tension of titanium alloys Ti–(36–40)Zr–9Ta (at %) for medical use after hot rolling and quenching. After rolling, the alloys consist of α'- and β-phases. The results of the research show that the hardening of alloys leads to the almost complete dissolution of the β-phase and the release of α'- and α"-phases. Investigations of mechanical properties of alloys Ti–(36–40)Zr–9Ta (at %) show that, in terms of tensile strength, the studied alloys Ti–36Zr–9Ta, Ti–38Zr–9Ta, and Ti–40Zr–9Ta are similar to the VT6 alloy widely used for implants (σ = 835–1100 MPa), and, in terms of plasticity (δ = 15–21%) and low value of Young's modulus (E = 53–73 GPa), significantly exceeds it. [ABSTRACT FROM AUTHOR]

Metallic titanium ingots can be manufactured via thermal decomposition of titanium sulfides. In our previous study, we thermodynamically and experimentally investigated the phase relationship of titanium oxides and sulfides under carbothermic and hydrogen gas flow atmospheres, that is, non-carbothermic atmospheres. Recently, carbon neutral processes for metallurgical processes that use plant-based biomass, which plays essential roles in environmental protection, have been focused. In this study, the gasification behavior of biomass was investigated by thermal gravimetry-differential thermal analysis, and the deoxidization and sulfurization behaviors that generate titanium sulfides were also experimentally investigated. The gasification behavior differs according to the type of biomass, including the amounts of H2O in the biomass. The reaction temperature for CO2 generation decreased with increasing biomass H2O content. However, the total amounts of generated gas ratios of H2O/CO2 were hardly different, and the partial pressures of oxygen during gasification were also fixed as a function of temperature. The products were analyzed using X-ray diffractometry and identified as titanium disulfide (TiS2), similar to a carbothermic process. [ABSTRACT FROM AUTHOR]