Processing Of Titanium Alloys Research Articles

Study on electrochemical polishing mechanism of TC4 titanium alloy

To achieve a high-quality and precise surface on TC4 titanium alloy for demanding engineering applications, electrochemical polishing (ECP) technology was employed to investigate the polishing process of TC4 titanium alloy in an ethylene glycol-sodium chloride green electrolyte. The macro and micro morphology, surface roughness, material removal rate, surface elements, surface corrosion resistance, and surface hardness of TC4 titanium alloy were measured before and after polishing. Single-factor experiments were conducted to explore the effects of processing gap, electrolyte temperature, polishing voltage, and polishing time on TC4 titanium alloy surface quality. Optimal polishing parameters were determined to be an electrode gap of 12 mm, a voltage of 20 V, a temperature of 40 °C, and a polishing time of 10 min. The experimental results indicated that after electrochemical polishing, the workpiece surface roughness Ra decreased from 256 nm to 25 nm, achieving a roughness reduction rate of 90.23%, the material removal rate was 3.348 μm min−1. The self-corrosion potential of the polished surface increased from −0.416 V to −0.375 V and the self-corrosion current density decreased from 4.447 × 10−7 A·cm−2 to 1.873 × 10−7 A·cm−2, the surface indentation hardness of the workpiece decreased from 5.8669 GPa to 4.6726 GPa. Based on the characterization of polished surface, the mechanism of electrochemical polishing of TC4 titanium alloy was proposed. The results demonstrate that electrochemical polishing of TC4 titanium alloy is highly efficient, involves no mechanical action, and causes no subsurface damage, making it a promising technology to meet medical requirements.

Numerical simulation of keyhole-induced pores for TA15 in laser powder bed fusion (L-PBF)

In the complex laser powder bed fusion (L-PBF) process, the occurrence of pores is often triggered when localized temperatures of the materials exceed their boiling point, posing a significant impediment to the overall quality of manufactured parts. In this work, considering the thermophysical properties and latent heat of phase transformation of the material, the formation and evolution of keyholes and pores during the L-PBF single-track processing of TA15 titanium alloy was investigated using X-ray computed tomography (X-CT) and FLOW-3D finite volume analysis software coupled with multiphysics fields. The simulated molten pool characteristics generally agree with the experimental data, including internal pores The results showed that the evolution of keyholes is mainly attributed to surface tension and recoil pressure, the Marangoni flow and surface tension contributed to closed localized cooling regions on the keyhole walls to generate pores. Additionally, the Marangoni flow and buoyancy effects lead to pore motion within the molten pool. Furthermore, the laser energy density is inherently related to the total pore counts and the mean penetration depth of keyholes, respectively. Understanding the underlying physical mechanisms helps to optimize process parameters and reduce pores in L-PBF, ultimately enhancing the quality of the additively manufactured parts.

A predictive mesoscale model for continuous dynamic recrystallization

Thermomechanical processing of titanium alloys often requires complex routes to achieve the desired final microstructure. Recent advances in modeling and simulation tools have facilitated the optimization of these processing routes. However, existing models often fail to accurately predict microstructural changes at large deformations. In this study, we refine the physical principles of an existing mean-field model and propose a calibration method that uses experimental results under isothermal conditions, accounting for the actual local deformation within the workpiece. This new approach improves the predictability of microstructural changes due to continuous dynamic recrystallization during torsion and compression experiments. Additionally, we integrate the model into the commercial FEM-based DEFORM™ 2D software to predict the local microstructure evolution within hot torsion specimens thermomechanically treated by resistive heating. Validation using non-isothermal deformation tests demonstrates that the model provides realistic simulations at high strain rates, where adiabatic heat modifies temperature, flow stress and microstructure. This study demonstrates the intrinsic correlation between microstructure, flow behavior, and workpiece geometry, considering the impact of deformation history in thermomechanical processes.

A comprehensive mean-field approach to simulate the microstructure during the hot forming of Ti-17

Thermomechanical processing of titanium alloys involves several hot forming steps to shape the workpiece and achieve a final microstructure that meets the desired mechanical properties. While mean-field models are commonly used to design the process and understand the influence of the processing route on the final microstructure, they cannot provide detailed spatial information on the local microstructure and stress evolution during the deformation of a workpiece. To address this limitation, we propose a comprehensive approach in which the mean-field model is validated in a region of a cylindrical workpiece at a constant strain rate and temperature during deformation. The validated model is integrated as a material model into a finite element-based software to analyse the effect of the thermomechanical history on the local microstructural and mechanical responses of the α and β phases. The model robustly predicts the role of the α-phase in the microstructural evolution of the β-phase, the α-dynamic globularisation kinetics in regions with different thermomechanical histories, and the influence of strain rate jumps on β-microstructural and mechanical responses. This comprehensive approach provides valuable insights into the intricate interplay between processing parameters, microstructure, and thermomechanical response in titanium alloys.

An Investigation of the Efficient-Precise Continuous Electrochemical Grinding Process of Ti-6Al-4V.

Titanium alloys have many excellent characteristics, and they are widely used in aerospace, biomedicine, and precision engineering. Meanwhile, titanium alloys are difficult to machine and passivate readily. Electrochemical grinding (ECG) is an ideal technology for the efficient-precise machining of titanium alloys. In the ECG process of titanium alloys, the common approach of applying high voltage and active electrolytes to achieve high efficiency of material removal will lead to serious stray corrosion, and the time utilized for the subsequent finishing will be extended greatly. Therefore, the application of ECG in the field of high efficiency and precision machining of titanium alloys is limited. In order to address the aforementioned issues, the present study proposed an efficient-precise continuous ECG (E-P-C-ECG) process for Ti-6Al-4V applying high-pulsed voltage with an optimized duty cycle and low DC voltage in the efficient ECG stage and precise ECG stage, respectively, without changing the grinding wheel. According to the result of the passivation properties tests, the ideal electrolyte was selected. Optimization of the process parameters was implemented experimentally to improve the processing efficiency and precision of ECG of Ti-6Al-4V. Utilizing the process advantages of the proposed process, a thin-walled structure of Ti-6Al-4V was obtained with high efficiency and precision. Compared to the conventional mechanical grinding process, the compressive residual stress of the machined surface and the processing time were reduced by 90.5% and 63.3% respectively, and both the surface roughness and tool wear were obviously improved.

Online Detection of Laser Welding Penetration Depth Based on Multi-Sensor Features.

The accurate online detection of laser welding penetration depth has been a critical problem to which the industry has paid the most attention. Aiming at the laser welding process of TC4 titanium alloy, a multi-sensor monitoring system that obtained the keyhole/molten pool images and laser-induced plasma spectrum was built. The influences of laser power on the keyhole/molten pool morphologies and plasma thermo-mechanical characteristics were investigated. The results showed that there were significant correlations among the variations of the keyhole-molten pool, plasma spectrum, and penetration depth. The image features and spectral features were extracted by image processing and dimension-reduction methods, respectively. Moreover, several penetration depth prediction models based on single-sensor features and multi-sensor features were established. The mean square error of the neural network model built by multi-sensor features was 0.0162, which was smaller than that of the model built by single-sensor features. The established high-precision model provided a theoretical basis for real-time feedback control of the penetration depth in the laser welding process.

Porous titanium alloys for medical application: Progress in preparation process and surface modification research

Excellent mechanical properties and biocompatibility are the most sought-after attributes in biomedical materials for the regeneration of damaged tissues. However, conventional dense titanium alloys possess a modulus significantly higher than that of human tissues, leading to potential stress-shielding effects. Medical porous titanium alloys can reduce the elastic modulus of the material, promote tissue fixation and vascular regeneration, and improve the suitability for human tissue properties. With the continuous development of technology, the preparation process of porous titanium alloys has undergone a series of multifaceted transformations and improvements in the aspects of powder sintering, fiber preparation, and additive manufacturing processes, and its structural characteristics and mechanical properties are constantly evolving in a controllable direction. Alongside the enhancement of the material’s mechanical properties through porous design, optimization of the properties at the implant-tissue interface also leads to improved antimicrobial and osteogenic properties of porous titanium. Due to the complex internal structure of porous titanium alloys, surface modification is mainly carried out in fluid media, which is realized by morphological modification and the introduction of functional substances. Over time, the surface modification of porous titanium alloys for medical applications has progressed from morphological modification and introduction of chemical composition to the loading of bioactive substances. This evolution aims to enhance safety and efficiency in the use of these materials. This paper reviews the preparation and surface modification processes of porous titanium alloys for medical use and summarizes the advantages, disadvantages, and influencing factors among different processes, with a view to providing new ideas for the development of porous implants for medical use.

Effect of texture on the room temperature tensile and creep properties of Ti–6Al–4V plate with large thickness

Texture is inevitably generated during the rolling process of titanium alloys, which has a significant impact on mechanical properties. The relationship between microstructure, texture and mechanical properties of the rolled Ti–6Al–4V alloy plate with large thickness was systematically investigated in this study. The texture type varied with the thickness of the plate. The basal pole concentrated in the transverse direction (TD) at the surface of the plate and tilted from TD towards the rolling direction (RD) at the quarter thickness of the plate. For the center of the plate, the basal pole had peaks concentrated close to both TD and RD. Tensile tests indicated that TD samples not only have high strength but also maintain good plasticity compared with RD and the normal direction (ND) samples. The yield anisotropy could be explained by the difficulty of prismatic and basal dislocation slip. The cold creep behavior of the thick plate depended on both Schmid factor of dislocation slip and grain size. Moreover, the strain hardening exponent was positively correlated with cold creep strain. Abundant prismatic <a> and pyramidal <c+a> dislocations were activated, and slip transfer and cross-slip made the dislocation slip distance longer, which contributed to creep strain and thus reduced the creep resistance of ND sample.

Numerical Simulation-Based Study on the Microstructure of TC4 Titanium Alloy in CMT Additive Manufacturing

This thesis explores the thermal and mechanical phenomena occurring during the Cold Metal Transfer (CMT) additive manufacturing process of TC4 titanium alloy. The investigation delves into the effects of layer-by-layer deposition on the thermal cycles, stress distribution, and microstructural evolution of the additive manufactured specimens. Key findings include the identification of thermal accumulation with increasing deposition layers, leading to a decrease in cooling rates and a slight increase in the peak molten pool temperatures. The temperature profiles on the substrate exhibit cyclic patterns of peaks and troughs, which become smoother and exhibit less variance between maximum and minimum temperatures as deposition progresses. Stress analysis reveals that equivalent stress within the deposited layers decreases with the number of layers. This is attributed to the thermal stress accumulation and stress cycles induced by multiple thermal cycles, which initially increase the equivalent stress. However, a reduction in cooling rates over time and the effects of remelting facilitate the release of interlayer stress, resulting in minimal residual stress within the cooled specimens. Microstructurally, the TC4 titanium alloy specimens are characterized by the presence of primary β phase spanning across multiple deposition layers, growing in the direction of additive manufacturing. The accumulated heat input from increased layering enhances the growth of the primary β phase.The specimens' microstructure features a basketweave pattern comprised of α' martensite, α, and β phases, with α' martensite directly transformed from the primary β phase. Repeated heating cycles foster diverse pathways for the secondary α phase's formation, leading to more pronounced, directionally parallel α phases and extensive basketweave structures within the specimen layers. Higher temperature gradients at specimen edges encourage the formation of needle-like α' martensite. This thesis contributes to the understanding of the thermal behavior, stress dynamics, and microstructural characteristics in TC4 titanium alloy during CMT additive manufacturing, highlighting the interplay between process parameters, thermal management, and material response.

The robot grinding and polishing of additive aviation titanium alloy blades: a review

PurposeThe purpose of this review is to comprehensively consider the material properties and processing of additive titanium alloy and provide a new perspective for the robotic grinding and polishing of additive titanium alloy blades to ensure the surface integrity and machining accuracy of the blades.Design/methodology/approachAt present, robot grinding and polishing are mainstream processing methods in blade automatic processing. This review systematically summarizes the processing characteristics and processing methods of additive manufacturing (AM) titanium alloy blades. On the one hand, the unique manufacturing process and thermal effect of AM have created the unique processing characteristics of additive titanium alloy blades. On the other hand, the robot grinding and polishing process needs to incorporate the material removal model into the traditional processing flow according to the processing characteristics of the additive titanium alloy.FindingsRobot belt grinding can solve the processing problem of additive titanium alloy blades. The complex surface of the blade generates a robot grinding trajectory through trajectory planning. The trajectory planning of the robot profoundly affects the machining accuracy and surface quality of the blade. Subsequent research is needed to solve the problems of high machining accuracy of blade profiles, complex surface material removal models and uneven distribution of blade machining allowance. In the process parameters of the robot, the grinding parameters, trajectory planning and error compensation affect the surface quality of the blade through the material removal method, grinding force and grinding temperature. The machining accuracy of the blade surface is affected by robot vibration and stiffness.Originality/valueThis review systematically summarizes the processing characteristics and processing methods of aviation titanium alloy blades manufactured by AM. Combined with the material properties of additive titanium alloy, it provides a new idea for robot grinding and polishing of aviation titanium alloy blades manufactured by AM.

Research on surface roughness detection and prediction of ti-6Al-4v titanium alloy based on multi-feature fusion

Considering that titanium alloy is a critical aviation resource, ensuring its machining quality is of significant importance. Surface roughness remains a key parameter for surface quality inspection. This article introduces a multi-sensor titanium alloy milling monitoring system aimed at accurately monitoring surface quality during titanium alloy processing. Principal component analysis is conducted on three-dimensional milling force and vibration. We propose a multi-objective cutting parameter optimization procedure to simultaneously optimize multiple cutting parameters to improve surface roughness and tool life. Considering the high dependence of visual measurement on the light source, we strive to mitigate this limitation and improve prediction accuracy by considering one-dimensional and two-dimensional feature values. We establish a multidimensional signal feature surface roughness prediction system based on milling parameters, milling vibration, milling force, and texture image features. Using particle swarm algorithm and machine learning models, the undetermined parameters in the prediction system are obtained. The results show that the prediction accuracy of the multi-signal feature fusion surface roughness prediction system is 99.12%, with a mean square error of less than 0.01. The research can provide some theoretical guidance for the accurate monitoring of the surface quality of titanium alloy processing.

Research on Grinding Force Prediction of Flexible Abrasive Disc Grinding Process of TC17 Titanium Alloy

Abrasive disc grinding is currently a key manufacturing process to achieve better accuracy and high-quality surfaces of TC17 components. Grinding force, which results from the friction and elastic–plastic deformation during the contact and interaction between the abrasive grains and the workpiece, is a critical parameter that represents the grinding accuracy and efficiency. In order to understand the influence factors of grinding force, the characteristics of the flexible abrasive disc grinding process were studied. Considering the contact state between the abrasive tool and the workpiece, the theoretical model of normal grinding force was established in detail, from macro- and micro-perspectives. By conducting single-factor and orthogonal grinding experiments of TC17 components, the influence of different process parameters on the normal grinding force was revealed. The normal grinding force prediction models of the abrasive disc grinding process were developed based on the Box–Behnken design (BBD) and particle swarm optimization–back propagation (PSO-BP) neural networks, respectively. The results showed that the normal grinding force was negatively correlated with the disc rotational speed, and positively correlated with the contact angle, grinding depth, and feed rate, and the interaction of the factor feed rate and grinding depth was the more influential factor. Both the BBD and PSO-BP force models had good reliability and accuracy, and the mean absolute error (MAE) and mean relative error (MRE) of the above two prediction models were 0.22 N and 0.16 N, and 13.3% and 10.9%, respectively.

Fabrication of bio metallic titanium and titanium alloys by microwave energy–A review

Biomaterials play a crucial role in medical science to enhance the quality of human life. These materials help to repair or replace the failed tissues of the human body. A biomaterial should be biocompatible in service and affordable to the needy. Ti6Al4V is the commonly used biomaterial used for the replacement of different suffered tissue. But due to the release of Aluminium and vanadium ion research has been going on to remove this difficulty by adding other elements like Niobium (Nb), Tantalum (Ta), Zirconium (Zr) and Molybdinum (Mo) etc. Various traditional or advanced manufacturing of bio-metallic implants demands a large amount of material, energy, and manufacturing time. Microwave material processing improves the material yield by reducing energy consumption and shop-floor time without compromising product quality. It offers fast product development, better mechanical properties with low cost, and reduced manufacturing time. Recently microwave processing of biomaterial has attracted researchers to develop economical bioimplants. This review article explored the issues related to processing bio-metallic titanium and titanium alloys using microwave energy.

Study on the Effect of Electrolytes on Processing Efficiency and Accuracy of Titanium Alloy Utilizing Laser and Shaped Tube Electrochemical Machining.

Electrochemical machining (ECM) has become more prevalent in titanium alloy processing. However, the presence of the passivation layer on the titanium alloys significantly impacts the performance of ECM. In an attempt to overcome the passivation effects, a high-temperature electrolyte or the addition of halogen ions to the electrolyte has been used. Still, it often results in compromised machining accuracy and surface roughness. This study applied laser and shaped tube electrolytic machining (Laser-STEM) for titanium alloy drilling, where the laser was guided to the machining zone via total internal reflection. The performance of Laser-STEM using different types of electrolytes was compared. Further, the effects of laser power and pulse voltage on the machining side gap, material removal rate (MRR), and surface roughness were experimentally studied while drilling small holes in titanium alloy. The results indicated that the use of passivating electrolytes improved the machining precision, while the MRR decreased with an increase in laser power during Laser-STEM. The MRR showed an increase while using aggressive electrolytes; however, at the same time, the machining precision deteriorated with the increase in laser power. Particularly, the maximum feeding rate of 6.0 mm/min for the tool electrode was achieved using NaCl solution as the electrolyte during Laser-STEM, marking a 100% increase compared to the rate without the use of a laser. Moreover, the model and equivalent circuits were also established to illustrate the material removal mechanisms of Laser-STEM in different electrolytes. Lastly, the processing of deep small holes with a diameter of 1.5 mm, a depth of 38 mm, and a surface roughness of Ra 2 µm was achieved via Laser-STEM without the presence of a recast layer and heat-affected zones. In addition, the cross-inner flow channels in the titanium alloys were effectively processed.

Investigation of the Titanium Alloy Turning Process with Prime A Tools under High-Pressure Cooling Conditions

When turning titanium alloys, it is difficult to ensure the required quality with maximum machining efficiency. A typical problem in the turning process of titanium alloys is to achieve effective breaking and removal of chips from the machining zone. The combination of the new construction of cutting tools and machining methods in the machining of titanium alloys increases the efficiency of the machining. For this reason, the use of tools typical for the Prime Turning method in combination with the high-pressure cooling (HPC) method was analysed. The longitudinal turning of the Ti6Al4V ELI titanium alloy was performed using Sandvik Coromant grade 1115 carbide tools. An increase in the pressure of the cutting fluid to p = 70 bar was used. Measurements of the components of the total cutting force for finishing machining with variable cutting parameters in the range of: feed rates f = &lt;0.1;0.4&gt; mm/rev, cutting depth ap = &lt;0.25;1.0&gt; mm and cutting speed vc = &lt;40;80&gt; m/min were performed. It has been shown that the values of cutting force are mainly dependent on the feed and the depth of cut. An analysis of the forms of chips obtained is presented. The dependence of the applied cutting parameters on the value of the chip breakage coefficient Cch was determined. The method of searching for the maximum efficiency of the turning process was determined, taking into account the desired value of the chip breakage coefficient.

Towards sustainable manufacturing: Multiple optimization of surface roughness Ra, flank wear Vb in MQL-assisted milling of Titanium Alloy Ti-6Al-4V

This research focuses on the sustainable optimization of the milling process for Titanium Alloy Ti-6Al-4V using Minimum Quantity Lubrication (MQL) assistance. This experimental research investigates the effects of cutting parameters and lubrication conditions on the surface roughness ([Formula: see text]) and flank wear ([Formula: see text]) in the milling process of Titanium Alloy Ti-6Al-4V. The study aims to evaluate the influence of cutting speed ([Formula: see text]), feed rate ([Formula: see text]) and depth of cut ([Formula: see text]) on the selected machining performance indicators. The experiments were carried out using a DMG Mori Seiki DMU50 CNC center, and the workpiece samples were measured at [Formula: see text]. Three different lubrication conditions were employed, including dry machining, conventional flood cooling and Minimum Quantity Lubrication (MQL) using peanut oil. The cutting parameters were varied based on a Taguchi L9 orthogonal array design to explore the main effects of each parameter on [Formula: see text] and [Formula: see text]. The results reveal that cutting speed ([Formula: see text]) has the most significant influence on surface roughness, followed by feed rate ([Formula: see text]), while the impact of depth of cut ([Formula: see text] is negligible in comparison. Conversely, the coolant mode has the most significant impact on flank wear ([Formula: see text]), followed by feed rate ([Formula: see text]) and depth of cut ([Formula: see text]), while the influence of cutting speed ([Formula: see text] is relatively minor. Under the same cutting parameters, transitioning from dry machining to MQL led to a sharp decrease in [Formula: see text] from 170 to 100[Formula: see text][Formula: see text]m, and it increased to approximately 145[Formula: see text][Formula: see text]m when switching to flood cooling. Additionally, increasing the feed rate from 0.02 to 0.06[Formula: see text]mm/tooth reduced [Formula: see text] from around 135 to 120[Formula: see text][Formula: see text]m, but it significantly rose to approximately 165[Formula: see text][Formula: see text]m when the feed rate was further increased. Furthermore, the application of MQL with peanut oil as a lubricant and coolant demonstrated improvements in surface finish and reduced tool wear compared to dry and conventional flood cooling. The MQL approach led to better machining performance with lower [Formula: see text] and [Formula: see text] values. Overall, this study provides valuable insights into the effects of cutting parameters and lubrication conditions on surface roughness and flank wear in the milling process of Titanium Alloy Ti-6Al-4V. The findings offer practical guidelines for optimizing machining conditions to achieve desired surface quality and extend tool life while considering the environmental benefits of employing MQL in the manufacturing process.

Processing of titanium alloys with improved efficiency and accuracy by laser and electrochemical machining

Processing of titanium alloys with improved efficiency and accuracy by laser and electrochemical machining

Wear characteristics of PVD coated carbide tools in milling of TA15 titanium alloy

Titanium alloy, due to its small elastic modulus and poor thermal conductivity, is easy to exacerbate tool wear during milling which affects its machinability. In this work, an experimental investigation was conducted to analyze the effect of the properties and microstructure of different coatings on tool wear behavior and machining stability during the milling process of TA15 titanium alloy. Physical vapor deposition technology was applied to prepare AlTiSiN and AlZrTiN coatings on carbide samples, respectively, and their microstructures and mechanical properties were investigated. The results showed that AlZrTiN coating exhibited a higher elastic modulus, indicating that it had better resistance to peel off than AlTiSiN coating. Moreover, milling experiments were performed with AlTiSiN and AlZrTiN coated tools to investigate wear characteristics and mechanism. When milling TA15, the two coated tools mainly suffered adhesive wear and oxidation wear. AlZrTiN coated tool exhibited a better wear resistance during long time milling. The surface roughness of TA15 obtained by AlZrTiN coated tool was better than that by AlTiSiN coated tool, achieving approximately Ra0.089 µm. As a result, AlZrTiN coated tool exhibits a better cutting characteristic and is preferred for milling of TA15 titanium alloy.

Pemesinan Paduan Ti-6Al-4V ELI

Titanium alloy material Ti-6Al-4V ELI (Extra Low Interstitial) is a type of alloy that has very similar properties to Ti-6Al-4V (Grade 5) alloy, which is the most widely used material, but only differs in terms of properties. his tenacity. Ti-6Al-4V ELI has higher ductility and better fracture toughness. In addition, this material also has a good ability to work at high temperatures without losing its main properties. The main properties of this material are corrosion toughness at high temperatures and excellent weight to strength ratio. Referring to these advantages, the alloy material of the Ti-6Al-4V ELI type has been developed in many fields including the field of planting materials in the medical field, the aircraft industry, applications in the field of military weapons, the manufacture of racing vehicle components and also high pressure vessels for storing materials. low-temperature (cryogenic) liquid nitrogen [16].. During the machining process of titanium alloy, many things become obstacles because this material is a material that is difficult to machine. This is because the titanium alloy has high hardness, there is often a reaction between the cutting tool and the workpiece material during the cutting process, and there is an accumulation of high temperatures in the cutting area. Factors cutting speed and feed rate are the two dominant factors on the formation of cutting tool wear, both wear on the face or crater side. Damage to the cutting tool is also followed by damage to the surface of the workpiece being machined or the surface quality of the workpiece. The dominant wear that occurs in the rib face area is wear due to adhesion, notch wear, while wear in the crater area is diffusion that occurs during the machining process. Meanwhile, the cutting temperature has a direct impact on the surface quality of the workpiece being machined. The factor of high cutting speed with low feed rate is a combination of factors that provide good cutting force. Meanwhile, insert type cutting tools that have a hard coating, such as TiN, TiAlN and TiCrN play a significant role in the formation of tool wear. Likewise, hard coated tools provide better performance compared to uncoated insert tools. Machining with the Minimum Quantity Lubrication (MQL) method gives better results compared to dry machining and machining using flooded cooling.Keywords: machining, Ti-6Al-4V ELI, cutting tool, materials.

Strengthening effect of nano-rutile on Ti–3Zr–2Sn–3Mo–25Nb titanium alloy and mechanism of TiO2 phase transformation

The safety and stability of medical metal materials in the post-implantation period have always needed to be improved. Ti–3Zr–2Sn–3Mo–25Nb (TLM) near-β bio-titanium alloy has suitable biological properties and nontoxicity, by introducing nano-rutile particles in the micro-arc oxidation surface treatment process of TLM titanium alloy, can enhance its strength performance while retaining the original phase and excellent properties. The effects of nano-rutile on the microstructure and strength properties of micro-arc oxidation coating were tested and analyzed. The results showed that the addition of nano-rutile reduced the porosity and roughness of the coating, significantly increased the thickness, density, and especially the hardness. The self-corrosion potential increased from −0.345 to −0.272 V; the corrosion current decreased from 9.639 × 10−7 to 6.793 × 10−9 A/cm2. Furthermore, the friction coefficient decreased from 0.8 to 0.2, and the strength of fatigue wear and adhesive wear both attenuated. In addition, the chemical reactions that might occur during micro-arc oxidation were also speculated through the phase analysis, and the film-forming process and the influence of rutile doping on the oxidation process were also discussed. Moreover, the model of the nucleus in the TiO2 phase transition process was established and the relationship between the nucleation rate and the temperature was derived.