Machining Of Ti6Al4V Research Articles

Electric Discharge Machining of Titanium Alloy under Cu Mixed Dielectric Medium

Introduction: In the current research work, an attempt has been made to machine Ti6Al4V using Powder Mixed Electric Discharge Machining (PMEDM) technique. methods: The experiments were designed utilizing central composite response surface methodology by varying current, pulse on time, gap distance, and powder concentration at five different levels, whereas Material Removal Rate (MRR), Tool Wear Rate (TWR), and Surface Roughness (Ra) were documented as responses. The MRR reduced with an increase in powder concentration until the concentration reached 7.5g/l because incorporated particles observed the major proportion of heat, and at 10g/l, MRR increased due to the bridging effect. results: The TWR and Ra reduced with an escalation in powder concentration due to expansion in the spark gap, facilitating the flushing of machined debris. The surface topography revealed cracks, pits, globules, and craters. Moreover, with the addition of particles, surface quality improved owing to the elimination of re-melted layers. conclusion: The parameters were optimized using the Grey Relational Analysis (GRA), and the combination of 2.5g/l powder concentration, 20A current, 50µs ton, and 4mm gap distance offers the best machining performance.

Prospects Of Use And Processing Of Titanium Blanks Obtained By xBeam 3D Metal Printing Technology

The article presents the new range of additive technologies called xBeam 3D metal printing that allows the production of titanium alloy parts for the medicine, aeronautical and automotive industries. The new technology opens up essential challenges, such as identifying and analysing the optimal finishing machining strategies for this type of part. The article analyses the production and machining of TI6Al4V produced by Wire Arc. The research focuses on implementing optimal cutting modes to obtain the required surface quality. This article provides a better understanding of the machining of titanium blanks using this technology. The optimistic results make this method the best alternative to traditional casting technologies and powder metallurgy.

Fully coupled thermomechanical simulation of laser-assisted machining Ti6Al4V reveals the mechanism of morphological evolution during serrated chip formation

Fully coupled thermomechanical simulation of laser-assisted machining Ti6Al4V reveals the mechanism of morphological evolution during serrated chip formation

Finite element asnalysis of Ti1-xAlxN coated tools cutting performance and tool wear during Ti–6Al–4V milling

Ti–6Al–4V alloy, as a typical difficult-to-machine material, is prone to problems such as large cutting forces, high cutting temperatures, and serious tool wear during the cutting process. Ti1-xAlxN coated tools are widely used in machining Ti–6Al–4V alloys. The main wear forms of Ti1-xAlxN coated tools are coating cracking and delamination. After the coating has been delaminated, the tool substrate is in direct contact with the workpiece material, aggravating tool wear and shortening the tool life. Therefore, the milling process of Ti1-xAlxN coated tool cutting Ti–6Al–4V alloy was performed using FEM. The effects of Al contents (Ti0·48Al0·52N, Ti0·38Al0·62N), coating thickness (2, 3, 4 μm), and tool substrate (Cemented Carbide Grade K, M, P) of Ti1-xAlxN coated tools on the cutting performance (cutting force, cutting temperature, maximum principal stress, the temperature and stress of coating-substrate interface) and tool wear were discussed. The influence of the maximum principal stress, the temperature and stress of coating-substrate interface on tool wear were analyzed. This paper can provide a reference for the design and optimization of Ti1-xAlxN coated tools by investigating the wear of Ti1-xAlxN coated tools cutting titanium alloys, which can be used to slow tool wear and prolong tool life.

Effect of high-speed ultrasonic vibration cutting on the microstructure, surface integrity, and wear behavior of titanium alloy

Titanium alloys are widely used in aviation, marine, automotive, offshore, and medical fields. However, their poor wear resistance reduces the safety and reliability of components during service. Few study has been previously conducted on the wear resistance enhancement of titanium alloys (including Ti–6Al–4V alloy) processed by mechanical cutting. High-speed ultrasonic vibration cutting (HUVC) is an effective approach for improving the machinability of titanium alloys. In this study, we attempted to utilize HUVC improving the wear resistance of titanium alloys. After conducting high-speed turning (cutting speed within the range of 200–300 m/min), the surface integrities (surface roughness, microstructure, in-depth micro-hardness, and residual stress) of conventional cutting (CC)- and HUVC-machined samples were characterized. Experimental results demonstrated that, compared with CC, HUVC achieved a thicker plastic deformation layer (greater than 46.93 μm), lower surface roughness, higher surface micro-hardness (greater than 433 HV0.05), and higher compressive residual stress (up to −840 MPa). Moreover, surface nanocrystallization and gradient nanostructured layer were observed in HUVC-machined Ti–6Al–4V samples. In addition, compared with CC, HUVC effectively further reduced the friction coefficient and worn volume loss (decreased by 20.98%–25.59%) and ultimately improved the wear resistance. The hardness has a higher influence on the wear resistance of the machined Ti–6Al–4V alloy than the other surface integrity factors. Therefore, the proposed mechanical cutting operation was confirmed to improve the wear resistance of titanium alloys.

Sustainability analysis of new hybrid cooling/lubrication strategies during machining Ti6Al4V and Inconel 718 alloys

The necessity of achieving sustainable manufacturing processes, taking into account the economic and environmental balance, is a significant obstacle for many industries. This article investigates the comparative sustainability assessment of two difficult to cut superalloys (Ti6Al4V and Inconel 718) using a new hybrid sustainable machining strategy that combines ultrasonically assisted turning (UAT) with an environmentally friendly cooling and lubrication method (MQL and LCO2). The primary objective of this study is to examine the effects of the proposed strategy on the economic and carbon emission analysis, tool life, energy consumption, and surface roughness of Inconel 718 and Ti6Al4V alloys during machining. To evaluate the efficacy of the proposed strategy for the two alloys, an in-house UAT setup is used to conduct experiments employing a variety of cooling methods. It was found that Ti6Al4V emits roughly 40% less carbon than Inconel 718. The cost of machining Ti6Al4V and Inconel 718 in a cryogenic environment decreased by about 26% and 21%, compared to a dry environment. Moreover, while machining Ti6Al4V, more tool life has improved approximately by 6–65% and 9–35% compared to Inconel 718 in CT and UAT. Machining of Ti6Al4V consumes approximately 2–16% and 9–15% less energy compared to Inconel 718 under CT and UAT, respectively. Ti6Al4V lowers the surface roughness approximately by 21% and 15% compared to Inconel 718 when using CT and UAT, respectively.

Efficient and low-damage machining of Ti6Al4V: laser-assisted CBN belt grinding

ABSTRACT This study introduces a new method for efficient and low-damage machining of Ti6Al4V: laser-assisted CBN belt grinding. The impact of laser power and grinding depth on the machining behavior of the material is investigated, the elemental distribution and chemical state of the ground surface are analyzed, and the removal mechanism of laser-assisted CBN belt grinding is described. The results show that increasing laser power will improve processing efficiency, enhance plastic material removal, and improve surface quality; the tangential grinding force is decreased by 63.5% and the normal grinding force is decreased by 72.6% at the maximum laser power; a large amount of Ti and N are present on the ground surface, and they are present in the form of TiN compounds. This study is a guide to the research on efficient and low-damage machining of hard-to-process materials like titanium alloys.

Surface characteristics optimization of biocompatible Ti6Al4V with RCCD and NSGA II using die sinking EDM

Machining of titanium alloy grade V (Ti6Al4V) is very difficult by conventional metal cutting process due to low thermal conductivity, ability to retain strength at elevated temperature, tendency to work harden. This may result in high heat at the cutting zone and the generation of thermal stresses. Therefore, in the present research die-sinking electrical discharge machining is used to machine Ti6Al4v alloy. A non-dominated sorting genetic algorithm (NSGA II) coupled with rotary central composite design (RCCD) based on response surface methodology (RSM) is employed to optimize machining parameters in die-sinking electrical discharge (EDM) machining of Ti6Al4V. A quadratic mathematical model has been developed for material removal rate (MRR) and surface roughness (Ra) in terms of peak current (I), pulse on time (Ton) and pulse off time (Toff) as independent input parameters. Die-sinking EDM experiments are planned using RCCD based on response surface methodology. Results revealed that peak current is the most influencing EDM parameter on both MRR and Ra with PC of 35.86% and 57.10% respectively. MRR continuously increases with peak current. MRR firstly decreases and then increases with an increase in Ton. Ra continuously increases with peak current and starts decreasing after a coded value of 1.5. The Optimization result obtained by NSGA II is validated through confirmation experiments which are in good agreement with the experimental value with an absolute error of 6% and 4.8% in MRR and Ra respectively.

Overview of Machinability of Titanium Alloy (Ti6Al4V) and Selection of Machining Parameters

Abstract Machining of titanium alloy Ti6Al4V is a challenging task for the industry; however, there are some solutions to overcome these difficulties. One of those is optimizing the machining parameters. Machining of Ti6Al4V made by additive manufacturing is an emerging future and is even more difficult when comparing to standard Ti6Al4V alloy. There is lot of invention on Ti6AL4V 3D printed samples, but influence of machining post-printing is lacking. In additive manufacturing of Ti6Al4V alloy, it is necessary to make a finishing operation to improve the surface quality and to ensure precise geometry tolerances. During this process, it may affect the workpiece properties such as microhardness, microstructure, internal defect distribution, internal stresses. During printing there are lots of stresses created, heat treatment is done to normalize the parts. Machining (using milling machine) also causes internal stresses which can damage the surface and part itself. Optimisation of machining parameters and printing parameters can solve this issue. This study gives an overview of selection of machining parameters by considering all the previous relevant research.

WEDM process parameters optimization by preference-based CS & PSO algorithm for LCP

ABSTRACT Locking Compression Plates (LCP) are typically made of Ti6Al4V alloy. LCP is used to heal fractures of the bone. This article uses Wire Cut Electric Discharge Machining (WEDM) to machine Ti6Al4V alloy. Responses are optimized by two metaheuristic algorithms, the cuckoo search algorithm (CS) and particle swarm optimization (PSO). The cuckoo search algorithm shows that the maximum MRR is 59.4312 mg/min & the maximum cutting speed is 5.0625 mm/min. The single-objective PSO shows a maximum MRR of 59.3632 mg/min & the maximum cutting speed is 5.0155 mm/min. The GRA revealed that the optimum weight for MRR and cutting speed is 48.868% and 51.132% respectively. Scanning electron microscope analysis indicates proper biocompatibility after machining. This article compares CS and PSO with similar calculations for the t-test and found that the p-values for MRR and Cutting speed are 0.9432 and 0.9919.

Bio-dielectric based eco-friendly electrical discharge machining of Ti6Al4V: assessment of the machined-surface morphology and micro-hardness

Bio-dielectric based eco-friendly electrical discharge machining of Ti6Al4V: assessment of the machined-surface morphology and micro-hardness

Bio-dielectric based eco-friendly electrical discharge machining of Ti6Al4V: assessment of the machined-surface morphology and micro-hardness

Bio-dielectric based eco-friendly electrical discharge machining of Ti6Al4V: assessment of the machined-surface morphology and micro-hardness

An Analytical and Experimental Study on Cutting Characteristics and Transient Cutting Force Modeling in Feed Directional Ultrasonic Vibration-Assisted Cutting of High Strength Alloys.

Ultrasonic vibration-assisted cutting (UVC) is progressively being used in machining as it can significantly promote the fabrication process. However, the ultrasonic vibration affecting the cutting process is still controversial. The full-transient cutting process is proposed in this study to analyze the affecting mechanism induced by ultrasonic vibration in the cutting process. This novel model is the first developed based on the fact that ultrasonic vibration would change mechanical behaviors and the cutting process. For example, the reduction of shear flowing stress in the primary shear zone and alteration of the shear angle in the UVC process. Then, considering those coupled effects, a novel model is proposed to determine the average and transient cutting forces. Here, insight and understanding into the physical phenomenon in UVC are provided. The effectiveness of the proposed model is verified by comparison with experimental results and analytical models available in the literature, with cutting parameters varying from macro to micro-scale. The results show that the ultrasonic vibration affects the cutting process in a complicated way, which is determined by transient characteristics, acoustic softening, thermal softening, plowing, and friction. Those effects on cutting performances in the UVC process under various cutting scenarios are investigated and discussed systematically. The average deviation of cutting forces between experiments and values predicted by the proposed model for Ti6Al4V, AISI 1045, and Al6063 is about 7%, 10.2%, and 11%, respectively. The deviation decreases with the increase of cutting speed in the machining of Ti6Al4V, which is different from the machining of other materials. This is contributed by the varied effect of ultrasonic vibration on the cutting process.

Grain erosion wear properties and grinding performance of porous aggregated cubic boron nitride abrasive wheels

Cubic boron nitride (cBN) superabrasive grinding wheels exhibit unique advantages in the grinding of difficult-to-cut materials with high strength and toughness, such as titanium alloys and superalloys. However, grinding with multilayered metallic cBN superabrasive wheels faces problems in terms of grain wear resistance, the chip storage capability of the working layers and the stability and controllability of the dressing process. Therefore, in this work, novel metallic cBN superabrasive wheels with aggregated cBN (AcBN) grains and open pore structures were fabricated to improve machining efficiency and surface quality. Prior to the grinding trials, the air-borne abrasive blasting process was conducted and the abrasive blasting parameters were optimized in view of wear properties of cBN grains and metallic matrix materials. Subsequently, the comparative experiments were performed and then the variations in grinding force and force ratio, grinding temperature, tool wear morphology and ground surface quality of the multilayered AcBN grinding wheels were investigated during machining Ti–6Al–4V alloys. In consideration of the variations of grain erosion wear volume and material removal rate per unit of pure metallic matrix materials as the abrasive blasting parameters changes, the optimal abrasive blasting parameters were identified as the SiC abrasive mesh size of 60# and the abrasive blasting distance and time of 60 mm and 15 s, respectively. The as-developed AcBN grains exhibited better fracture toughness and impact resistance than monocrystalline cBN (McBN) grains because of the existence of metal-bonded materials amongst multiple cBN particles that decreased crack propagation inside whole grains. The metallic porous AcBN wheels had lower grinding forces and temperature and better ground surface quality than vitrified McBN wheels due to the constant layer-by-layer exposure of cBN particles in the working layer of AcBN wheels.

Finite Element Investigation on Cutting Force and Residual Stress in 3D Elliptical Vibration Cutting Ti6Al4V.

Titanium alloy is a typical difficult-to-machine material with features of superhigh strength and hardness, and low elastic modulus. It is difficult to guarantee the processing quality and efficiency due to the high cutting force and tool wear in conventional cutting. Elliptical vibration cutting (EVC) as an effective method can improve the machinability of titanium alloys. In this paper, the finite element method (FEM) was adopted to study the cutting force and residual stress of 3D EVC in machining of Ti6Al4V. The Johnson-Cook constitutive model was utilized to illustrate the plastic behavior of Ti6Al4V alloy. The kinematics of the 3D EVC was described, and then the influence of various cutting speeds, vibration amplitudes, vibration frequencies and depths of cut on cutting force and residual stress were carried out and analyzed. The simulation results show that the cutting speed, vibration amplitude a, vibration frequency and depth of cut have larger effect on principal force. In addition, the compressive stress layer can be easily obtained near the machined surface by using 3D EVC, which is helpful to improve the working performance of workpiece.

A study on the influence of thermally assisted novel hybrid methods on the drilling behavior of Ti6Al4V alloy

The paper focuses on the drilling behavior of Ti6Al4V alloy under dry, MQL, hot (also expressed as heat-assisted machining), and hybrid (hot+MQL) environments. The surface roughness and morphologies, power consumption, drilling force, microhardness, and microstructural behavior using electron backscatter diffraction (EBSD) analysis were studied. As a result, the lowest roughness value was obtained in the MQL, followed by dry, hot and hybrid drilling environments. Based on SEM investigation on machined surfaces, the defects i.e., smearing, chip debris and side flow were found to be the main causes of poor surface quality, especially under hot and hybrid-assisted drilling environments. According to the Euler color distribution, the hot working affected the machined surface up to the bulk material with a length of 98 µm. The hot drilling process led to the recrystallization of the grain structure, and the distribution, sizes, and characteristics of the phases were affected by the temperatures. A partially recrystallized grain structure was observed in the IPF maps of the hybrid drilling environment at a distance of 10 µm from the machined surface. The crystal orientation of machined Ti6Al4V under hybrid-assisted environment was very similar to dry machined crystal orientation indicating stability in the microstructure.

High-efficient compound sinking machining of Ti6Al4V with the assistance of oxygen

ABSTRACT Arc machining is suitable for efficiently processing typical difficult-to-cut material Ti6Al4V. Traditional arc sinking machining commonly uses water-based dielectric because of its safety and good cooling capacity. However, water-based dielectric generally has high conductivity that causes frequent short circuits and strong electrolytic reactions during machining, thereby reducing machining stability and deteriorating machining performance. This paper proposes a novel high-efficient compound sinking machining that combines arc machining with electrical discharge machining (EDM). The dielectric is formed by dispersing oxygen into deionized water, thus reducing the shortcomings of traditional water-based dielectric and introducing the advantages of gas-based one. The feasibility of the proposed method is systematically studied compared to the method that uses deionized water. Influences of oxygen pressure, pulse duration, and peak current are investigated. Characteristics of surface topography and recast layer are also studied. Results suggest that the properties of dielectric improve, and the machining stability and machining intensity increase with the assistance of oxygen. Therefore, compared with using deionized water, the proposed method shows better processing characteristics, including larger material removal rate (MRR), smaller relative electrode wear rate (REWR), and thinner recast layers. The proposed method is promising to process Ti6Al4V due to its high efficiency and environment-friendly properties.

Determination of Optimum Machining Parameters for Face Milling Process of Ti6A14V Metal Matrix Composite.

This paper shows the novel approach of Taguchi-Based Grey Relational Analysis of Ti6Al4V Machining parameter. Ti6Al4V metal matrix composite has been fabricated using the powder metallurgy route. Here, all the components of TI6Al4V machining forces, including longitudinal force (Fx), radial force (Fy), tangential force (Fz), surface roughness and material removal rate (MRR) are measured during the facing operation. The effect of three process parameters, cutting speed, tool feed and cutting depth, is being studied on the matching responses. Orthogonal design of experiment (Taguchi L9) has been adopted to execute the process parameters in each level. To validate the process output parameters, the Grey Relational Analysis (GRA) optimization approach was applied. The percentage contribution of machining parameters to the parameter of response performance was interpreted through variance analysis (ANOVA). Through the GRA process, the emphasis was on the fact that for TI6Al4V metal matrix composite among all machining parameters, tool feed serves as the highest contribution to the output responses accompanied by the cutting depth with the cutting speed in addition. From optimal testing, it is found that for minimization of machining forces, maximization of MRR and minimization of Ra, the best combinations of input parameters are the 2nd stage of cutting speed (175 m/min), the 3rd stage of feed (0.25 mm/edge) as well as the 2nd stage of cutting depth (1.2 mm). It is also found that hardness of Ti6Al4V MMC is 59.4 HRA and composition of that material remain the same after milling operation.

Microstructure and mechanical properties of a novel PM Ti–2Al–1.3V alloy in different heat treatment conditions

ABSTRACT A novel Ti–2Al–1.3V (wt.%) alloy was prepared by thermomechanical consolidation of a composite powder produced by high-energy ball milling of a mixture of TiH2 granules with a low oxygen content (0.1wt.%) and Ti–6Al–4V machining chips with a high oxygen content (0.8wt.%) at a mass ratio of 2:1. The microstructures and mechanical properties of the alloy in as-extruded state and after different heat treatments were investigated. The as-extruded alloy exhibits a martensite microstructure consisting of ultrafine and nanometer sized α’ laths and aciculae and domains of layered structure containing δ(TiH) layers. The alloy in this state is brittle and fractures prematurely before yielding due to the ultrafine martensitic microstructure and hydrogen embrittlement associated with the high hydrogen content of the alloy. After vacuum annealing at 700°C for 6 h followed by furnace cooling, the alloy is further dehydrogenated with the hydrogen content being reduced to 0.008wt.%, the microstructure of the alloy changes into a full α/β lamellar microstructure with the continuous and discontinuous β layers being only 80–90 nm thick and the lamellar colony sizes being 10–30μm. The fine structured alloy in this heat treatment condition shows an excellent combination of high tensile yield strength of 996 MPa and ductility of 13.9%. After a further heat treatment of 980°C for 1 h followed by air cooling, the microstructure of the alloy consists of equiaxed α grains and α/βt lamellar structured domains (βt = β transformed structure), and unfortunately, this microstructure leads to a significant decrease of both the tensile yield strength (to 876 MPa) and the tensile ductility (to 7.4%). The fracture behavior of the alloy in different states is also studied, and the correlation between the microstructure and mechanical properties is discussed.

Effect of volcano-like textured coated tools on machining of Ti6Al4V: an experimental and simulative investigation

The present study was to reduce the adhesion and wear that happened on the rake face during machining of Ti6Al4V alloys by employing volcano-like textured coated tools. A combination of experimental and simulative investigation was adopted. DEFORM-3D software with updated Lagrangian formulation was used for numerical simulation, and the thermo-mechanical analysis was performed using Johnson–Cook material model to predict the cutting forces, cutting temperature, chip morphology, and tool wear. In cutting experiments, volcano-like textures with different area densities (10%, 20%, 30%) were fabricated by fiber laser on the rake face of cemented carbide tools close to the main cutting edge. Then, these textured tools were deposited with CrAlN coating through cathodic vacuum arc ion plating technique. Experiments in cutting Ti6Al4V alloys were carried out with the textured coated tools and non-textured coated tool under dry and wet cutting conditions. Then, cutting forces, chip morphology, and tool wear were investigated. The results showed that textured coated tools were superior to the conventional tool. Especially in wet cutting, the main cutting force and radial force of the coated tool with texture area density of 20% (VCT2) were reduced by 11.6% and 21.25%, respectively. Surface morphology of VCT2 tool had lower workpiece adhesion on the rake face. Therefore, VCT2 tool showed a better cutting performance. Finally, the mechanisms of textured coated tools under wet cutting conditions were proposed.