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The surface wettability of laser-textured Ti-6Al-4V and 316L SS is compared in this work. The surface of Ti-6Al-4V and 316L SS was micro-laser textured with varying dimple distances with the help of a nanosecond fiber laser. The composition of the material is evaluated using Energy Dispersive Spectroscopy and the surface roughness of the laser-textured samples was evaluated using a 3D optical profilometer. The results of the measurement of contact angle reveal information on the substrate’s wettability. The contact angle of Ti-6Al-4V was significantly reduced from 9$4.99^{\circ }$ to $56.46^{\circ }$ for 100$\mu$m dimple distance at 98% energy while 316L SS contact angle was reduced from $150^{\circ }$ to $60.21^{\circ }$ for 200$\mu$m at 98% energy.

The effects of microstructures of Ti-6Al-4V alloy on the flow stresses and fracture behaviors at quasi-static and dynamic deformation conditions were investigated. Specimens of different sizes and fractions of α globules in equiaxed and bimodal structures were compressed at the strain rate of 2×10⁻³/s and 3×10³/s using hydraulic testing machine and split Hopkinson pressure bar, respectively. The a globule size in equiaxed structure changed the level of flow stresses, but did not affect the strain hardening characteristics. Meanwhile, the volume fraction of α globule (or lamellar phase) in bimodal structures influenced both the flow stress and strain hardening exponent at quasi-static and dynamic deformation conditions. Bimodal structure of 50% lamellar fraction is considered to be more favorable in dynamic deformation condition at strain rate regime of 3×10³/s than equiaxed or bimodal one having higher lamellar fraction.

The blended elemental (BE) route is currently the main way for obtaining cost-affordable titanium alloys. Via post-consolidation processes like hot isostatic pressing (HIP) or thermomechanical processing, the material can improve its mechanical properties. In this work, a titanium alloy is processed via the BE approach, combined with thermomechanical processing of the sintered billets and subsequently heat treated. The tensile behavior of the sintered, extruded and heat-treated Ti-6Al-4V alloy was studied, finding an overall improvement of the properties after extrusion and a considerable increase in strength without compromising ductility after heat treatment. The high cycle fatigue behavior of the as-extruded alloy was studied by means of axial testing. There is a strong dependence between the location of the initiation of failure of the alloy and its fatigue life, but the defects that initiated failure were facets, not pores. The fatigue life of the as-extruded alloy is comparable to that of other fully-dense powder metallurgy (PM) and wrought Ti-6Al-4V alloys. These findings encourage the use of this route of processing as a balanced approach between low-cost and high-performance titanium alloys.

Ti-6Al-4V alloy is widely used for the deep-sea manned submersible. In addition to the normal cyclic loading, the manned cabin will experience a period of dwell time in each cycle during their service life. In this research, the fatigue and dwell-fatigue crack growth behavior of Ti-6Al-4V alloy under different dwell time were studied experimentally. The mechanism of dwell-fatigue crack growth was investigated. The acceleration phenomenon of the dwell-fatigue crack growth can be directly observed in the experiment. The relationship between the crack length and the dwell time was captured under different $\mathrm{\Delta }K$ within one cycle. The results presented that there is a saturation time for the dwell-fatigue crack growth. A prediction model is proposed to predict the dwell-fatigue crack growth behavior considering the effects of dwell time.

The grinding process of Titanium (Ti) alloys is extremely difficult as the cutting temperature is much higher than other machining processes due to the low thermal conductivity, high chemical reactivity, and rapid work hardening during machining of Ti alloys. This research investigates the effect of technology parameters on the surface roughness in the surface grinding of Ti–6Al–4V (Ti64) alloy with resinoid cBN grinding wheel. The experimental results show that the surface roughness is significantly affected by the feed rate, depth of cut (DOC) and cooling condition. Increasing feed rate or DOC all provides the higher surface roughness. The surface roughness obtained in the wet grinding is higher than those of the dry cutting. The scanning electron microscopy (SEM) images of Ti64 surfaces show that the machining surface with fewer defects can be produced with wet grinding process.

Modeling the impact of a laser heat source on Ti6Al4V deposition is crucial for optimizing additive manufacturing, particularly in multi-layer contexts. This modeling provides insights into the material’s behavior during the Ti6Al4V manufacturing process. In this study, simulations using MSC Marc were conducted to model the impact of a laser heat source on the deposition of the multi-layer Ti–6Al–4V (abbreviated as Ti6Al4V) using the Ti–6Al–4V metal powder, followed by SE-FIT simulation to characterize their deposition morphology. MSC Marc was utilized to simulate the impact of a laser heat source on the Ti6Al4V, with a focus on identifying the melting area. Thermal conductivity was represented in the form of a chart as a function of temperature. Next, the morphology after deposition was defined using SE-FIT based on volume and boundaries. In the MSC Marc numerical model, a combined heat transfer coefficient of radiation and convection was applied to the convective coefficient. In the section depicting the multi-layered deposition morphology, a laser with 750W power was utilized at a speed of 3.3mm/s. After simulation, the resulting layer height and appearance were compared with the literature for a 25-layer composite. The practical implications of this research extend to the broader field of laser-induced heat deposition on Ti6Al4V deposition, which has applications beyond titanium alloys. The findings may contribute to advancements in the design and manufacturing of various metal components, impacting industries such as automotive, electronics and energy.

By establishing a three-dimensional (3D) numerical simulation of the Ti-6Al-4V Gas Metal Argon Welding (GMAW) molten pool, the molten pool’s heat transfer and fluid flow behavior under a longitudinal magnetic field were investigated. The simulation results show that when the droplet enters the molten pool, the liquid metals on the molten pool’s surface symmetrically flow towards both sides of the molten pool from different angles. With the increase of the magnetic field strengthens, the temperature gradually decreases, and the fluid flow velocity increases continuously. Besides, the magnetic field strength is correlated positively with the molten pool’s size with a certain range of 0–0.03 T. However, when the magnetic field strengthens reach 0.04 T, the magnetic field is correlated negatively with the molten pool’s size. Because the Marangoni and buoyancy begin to weaken, the molten pool’s length change occurs before the width change. Simultaneously, a sizeable velocity region appears on the left side of the molten pool. Thus, the liquid metal gathers on the left side, resulting in the weld cross-section’s asymmetry. It can conclude that only when the magnetic strengthen keeps in the range of 0–0.03 T, the longitudinal magnetic field can make the molten pool’s surface profile smooth.

Micro-arc oxidation (MAO) is a novel technique for producing oxide films on metals like Al, Mg, Ti and Zr. A ceramic-like film containing Ca and P was deposited on Ti-6Al-4V substrate by MAO in an electrolytic solution using a pulsed power supply. XRD indicated that the film was a mixture of anatase, rutile and VO. SEM showed that the surface of the film was microporous with 1–2 μm pores. EDS gave the element distributions of the cross-section. The result indicated that elements like Ca and P could be incorporated into the film during MAO process. The microhardness test showed that the film had an average hardness of 540 HV_0.025.

The main purpose of the current research work is to identify and investigate a novel method of holding an intermediate metal and to evaluate its metallurgical and mechanical properties. Copper was used as an interlayer material for the welding of this dissimilar Ti–6Al–4V (Ti alloy) and 304L stainless steel (SS). The study shows that the input parameters and surface geometry played a very significant role in producing a good quality joints with minimum heat affected zone and metal loss. A sound weld was achieved between Ti–6Al–4V and SS304L, on the basis of the earlier experiments conducted by the authors in their laboratory, by using copper rod as intermediate metal. Box–Behnken method was used for performing a minimum number of experiments for the study. In the present study, Ti–6Al–4V alloy and SS304L were joined by a novel method of holding the interlayer and new surface geometry for the interlayer. Initially, the drop test was used for determining the quality of the fabricated joint and, subsequently, non-destructive techniques like radiography and C-scan were used. Further optical micrograph, SEM–EDS, hardness and tensile test were done for understanding the performance of the joint.

In order to improve the wear resistance of Ti alloys, different mass ratios of Ti-Si-Al powders were designed to fabricate hard phases reinforced intermetallic matrix composite coatings on the Ti-6Al-4V substrate by laser cladding. The corresponding coatings were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and high resolution transmission microscopy (HRTEM). The HV-1000 hardness tester and MM200 wear test machine were employed to test the hardness and the wear resistance of the composite coatings, respectively. The composite coatings mainly consisted of the reinforcements of Ti₅Si₃, Ti₃AlC₂ and Ti₇Al₅Si${}_{12}$ and the matrix of Ti₃Al, TiAl, TiAl₃ and $\alpha$-Ti. The micro-hardness of the Ti-35Al-15Si coating was from 956 HV${}_{0.2}$ to 1130 HV${}_{0.2}$, which was approximately 3–4 times of the substrate and the highest in the three samples. The wear rate of the Ti-35Al-15Si coating was 0.023cm³$\cdot$min${}^{-1}$, which was about 1/4 of the Ti-6Al-4V substrate. It was the lowest in the three samples.

After the damaged blade is repaired by laser cladding, the quality of the recontouring by milling determines its working performance in reservice. Ti-6Al-4V, titanium alloy, commonly used as the material of manufacturing aero-engine blades, is selected as the experiment material. Laser cladding technology is used to prepare a cladding layer, and milling experiments are carried out on the cladding layer. The effects of milling process parameters on the milling force, roughness, and surface topography are studied. The results show that when the milling speed ($v$) increases to 50m/min, the milling force and roughness ($R_a$) reach the maximum and at this moment the surface topography is the worst. Afterwards, with an increase in $v$, both the milling force and $R_a$ decrease in proportion, and the surface topography also becomes better. As the feed per tooth ($f_z$) increases, the milling force and $R_a$ also increase. However, the increasing trend gradually slows down. After $f_z$ increases to 0.08mm/z, the milling force and $R_a$ almost no longer increase and the surface topography remains almost unchanged. With an increase in milling width ($a_e$), the milling force and $R_a$ increase on the whole. But while $a_e$ increases from 0.4mm to 0.8mm, the milling force and $R_a$ increase very slowly. When $a_e$ reaches over 0.8mm, the milling force and $R_a$ increase rapidly again. As $a_e$ changes, the surface topography changes according to the milling force and roughness. On this basis, it is found that while machining a laser cladding layer, the milling force directly affects the surface roughness and topography. Therefore, by adjusting $v$, $f_z$, and $a_e$, one can obtain the small milling force and good milling surface of the laser cladding TC4 layer.

The Ti/C modified layers were prepared on Ti–6Al–4V alloy by double glow plasma surface alloying technique. The microstructure and composition of the modified layers were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The bonding strength, micro-hardness and friction performance of the modified layers were examined by the scratch tester, micro-hardness tester, reciprocating wear tester, and white light interferometer. The results show that both of the microstructure and properties of the Ti/C modified layer get the remarkable effects when the temperature reaches 910^∘C. Belonging to metallurgical bonding with the substrate, the modified layer possesses a continuous, compact and uniform packet-like particle structure. Compared with the Ti–6Al–4V substrate, the surface micro-hardness and wear resistance of Ti/C modified layer are significantly improved.

The dynamic mechanical properties of Ti-6Al-4V alloy prepared by laser direct deposition (LDD) at different strain rates are of great significance for the application of LDD technology in the manufacture and repair of aero-engine parts. The quasi-static tensile test and dynamic compression test of Ti-6Al-4V alloy prepared by LDD (LDD-Ti-6Al-4V) were carried out under the quasi-static and high strain rate using INSTRON-5982 tensile test equipment and Split Hopkinson pressure bar (SHPB) equipment. The true stress–strain curve is obtained, which indicates that the LDD-Ti-6Al-4V has a strain rate strengthening effect. Moreover, the Johnson–Cook (J–C) constitutive model of LDD-Ti-6Al-4V was fitted based on experimental data, and the experimental process of SHPB was numerically simulated. The simulation results are basically the same as the experimental results, which proves the correctness of the J–C constitutive model of LDD-Ti-6Al-4V.

Herein, a biomimetic coating of hydroxyapatite (HA)–Al₂O₃ and HA–ZrO₂ was deposited on Ti–6Al–4V-alloy using vacuum plasma spray (VPS) technique. The bond-coat of ZrO₂ has been introduced between the substrate and reinforced HA coatings to study the effect of bond-coat on structural, mechanical properties and electrochemical corrosion performance of the developed coatings. In addition, the impact of thermal treatment of coating was investigated on these properties too. Coating characteristics, such as morphology, porosity, surface roughness, and crystallinity were investigated. The corrosion performance of coatings was tested in Hank’s-based salt solution (HBSS). Significant enhancement in crystallinity and surface-hardness has been witnessed after heat treatment; nevertheless, porosity reduced. The electrochemical corrosion study revealed that the corrosion resistance of heat-treated samples was better than the as-sprayed coatings samples. The intensity of XRD peaks of all coatings increased after 24h immersion in HBSS for the electrochemical test in comparison to the intensity of peaks before the corrosion test.

The machining of Ti–6Al–4V alloy faces several confronts like generation of higher cutting temperature, fast tool wear, poor surface finish, higher tool vibration and chattering. Therefore, this research presents the detailed analysis of the surface roughness, tool flank wear, and amplitude of vibration and chip morphology under MQL enabled Ti–6Al–4V CNC machining. The experimental scheme is chosen as Taguchi L${}_{18}$ orthogonal array (OA) with cutting speed, feed and cutting depth considered as the input processing parameters. Further, WPCA optimization is implemented to evaluate the best combinations of input factors to get the optimal values of outputs.

The nitriding process is a surface treatment that improves the surface properties of titanium alloys and increases wear/corrosion resistance. This study investigates the structural and mechanical property changes in titanium alloy after nitriding. Micro-hardness differences between the nitrided and non-nitrided surface and morphological changes on the surface were determined. In addition to evaluating the effect of vanadium and aluminum ions on the nonnitrided surface, the impact of nitrided and non-nitrided surfaces on biofilm layer formation was investigated. It was determined that the TiN layer formed on the nitrided surface showed superior properties to its non-nitrided surface in the biofilm tests performed for 6 h. As a result of the tensile tests, it can be said that the nitriding process increases the elasticity module of the Ti–6Al–4V alloy and provides the material to have a more rigid structure. It was also analyzed using finite element analysis (FEA) of mechanical behaviors of the test sample under the tension loads.

Drilling, which constitutes one third of the machining operations, is widely used in many areas of the manufacturing industry. Various difficulties are encountered in the drilling process since the chip is formed in a closed limited chip flows. These difficulties directly affect the output parameters such as energy consumption, surface quality, and cutting force. Therefore, it is necessary to determine the ideal processing parameters to achieve the best performance. However, experimental research on machining processes requires both a long time and a high cost. For these reasons, machining outputs can be estimated by conducting drilling simulations with the finite element method. In this study, the finite element method is used in order to investigate the influence of different cutting parameters and different helix angles on the power and thrust force of Ti–6Al–4V (grade 5) alloy that is commonly used in the aviation industry. The study selected three different cutting speeds, feed rates, and helix angles as the cutting parameters. The experimental design was made according to the response surface method (RSM) Box–Behnken design in the Design-Expert program. Drilling simulations were performed using the ThirdWave AdvantEdge^TM software. The lowest thrust force measured is 1241.39 N at 40° helix angle, 2000-rpm revolution rate, and 0.05-mm/rev feed rate, while the lowest power consumed is 765.025 W at 30° helix angle, 1500-rpm revolution rate, and 0.05-mm/rev feed rate. As a result, it was determined that the most effective parameter for power and thrust force was the feed rate.

Nowadays, there has been continuous development of metallic biomaterials to meet special needs in the manufacturing of biomedical implants, units and systems so as to function well in the required environment. Developed biomaterials which possess exceptional properties in terms of biocompatibility and biomechanical compatibility require precision processing and machining to obtain the desired dimensional tolerances. Electrical discharge machining (EDM) is the noncontact or nontraditional process of machining that suits the precision machining of biomaterials. In this work, an effort was made to optimize the EDM parameters during machining of titanium-based biomaterials Ti-6AL-4V, so that the multi-objective responses could be obtained. The response surface method was used in designing the experiment, while the grey relational method was used to analyze the effect of multiple objectives into a single unit. The electrical parameters that were considered in this study include peak current, gap voltage, pulse turn-on and duty cycle. These parameters were set within the acceptable limits of the equipment. Three responses were studied, which are tool wear rates (TWRs), material removal rate (MRR) and surface roughness (SR). Using the signal-to-noise ratio and ANOVA optimum tool/electrode wear rate (TWR) is obtained at $5\times 10^{-5}$ g/min with process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=30$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%. Optimum values of material removal rate (MRR) are obtained as 0.01035g/min with process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=60$ V, $\mathrm{\text{Ton}}=140$  $\mu$s, $D=50$%. Optimum SR is observed as 2.258 $\mu$m with EDM process parameters $\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=90$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%. Surface characteristics are verified with SEM micrographs. Whereas, grey relation analysis predicted the multi-objective optimum response characteristics. Based on the grey relation grade, experiment number 7 ($\mathrm{\text{Ip}}=6$ A, $\mathrm{\text{Vg}}=90$ V, $\mathrm{\text{Ton}}=200$  $\mu$s, $D=65$%) secured the first rank among the experiments/trails.

This research focuses on wrought Ti-6Al-4V machining using coated carbide inserts under flood cooling to study the machinability characteristics. Machining parameters are optimized, and mathematical models are developed for correlations. Surface roughness lies between 0.215$\mu$m and 0.830$\mu$m and even below 1$\mu$m during machining. Flank wear lies within 0.033–0.16mm which is below the 0.2mm criteria of wear. Cutting temperature lies between 31^∘C and 158^∘C. The reduction of cutting temperature and chip serration under flood cooling and the subsequent transfer of heat from the shear zones help to generate good surface finish and may be due to the evolution of a lower wear rate. Abrasion, chipping, adhesion and built-up-edge are seen as major mechanisms of wear. The optimal conditions are found to be a depth of cut of 0.1mm, 0.1mm/rev feed rate and 70m/min cutting speed. There is an improvement in results at optimal conditions of 38.42% for Ra, 60.86% for VBc and 27% for $T$, respectively, than initial parametric conditions. Further, grey relational grade has been improved by 0.263. Machinability models developed through quadratic regression are observed to be significant.

Nowadays, it has become very difficult for the manufacturer to satisfy all its customers with satisfactory products, as they have different demands considering the responses. However, hard-to-machine materials are difficult to manufacture. This study explores the application of electro-discharge machining (EDM) of Ti–6Al–4V alloy with pulse duration (Ton), duty factor ($\tau )$, peak current (Ip) and gap voltage (Vg) as the control parameters using pure copper electrode. Machining effects are evaluated by performance characteristics including material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR) by considering the multi-criteria preference of the customers that vary with the preference of responses. For the experiment, proper orthogonal arrays are found out using Taguchi methodology. The optimum parametric settings were obtained by utility-concept-based Taguchi method which were compared with desirability-approach-based Taguchi. It was found that utility-concept-based Taguchi optimization methodology results in more feasible parametric setting which has also been confirmed by the validation experiments. The optimum values of process variables obtained were pulse duration of 30$\mu$s, duty factor of 9%, peak current of 10A and gap voltage of 6V to achieve maximum MRR and lower TWR with better surface finish to satisfy multi-user criteria.