Titanium Metal Matrix Composites Research Articles

Electrochemical Turning of (TiB + TiC)/TC4 Composites Using a Rectangular Cathode

The application of titanium metal matrix composites (Ti-MMCs) in the aerospace industry has increased significantly owing to their excellent mechanical properties. However, these properties also make Ti-MMCs difficult to machine. Many problems can occur with traditional turning, such as tool damage and low efficiency remain. Electrochemical machining is not limited by the physical properties of metal materials, making it an ideal machining method for Ti-MMCs, but there have been few articles evaluating electrochemical turning (ECT) in this application. Therefore, the purpose of this study was to use a cathode tool with a rectangular end face to realize the ECT of particle reinforced Ti-MMCs. Parametric experiments were conducted by varying the machining voltage, workpiece rotation speed, electrolyte pressure, and axial offset to determine their effects on the intermittent feed ECT of a cylindrical workpiece. Finally, intermittent feed ECT was performed on the cylindrical surface with the preferred machining parameters, and a machining area with a circular arc area of 4124 mm2, an average radial removal depth of 1.19 mm, and an average circular arc radius of 42.44 mm was obtained on the cylindrical workpiece, which verified the practical performance of the intermittent feed ECT method for machining titanium matrix composites.

A Review on Processing Routes, Properties, Applications, and Challenges of Titanium Metal Matrix Composite

Titanium is currently familiar for its light weight, high strength, and non-reactive nature over all the metals. Titanium metal matrix composites (TMCs) are very popular in the field of aerospace, automotive, defense, and biomedical because of their high specific strength, light weight, and biocompatibility nature. Some of the extensively used fabrication methods like powder metallurgy (PM), additive manufacturing (AM), and spark plasma sintering (SPS) have been reviewed here with some of the properties of TMCs. By varying various types of reinforcements, it is possible to achieve the required properties as per industrial and modern applications in TMC. This study also includes the consequence of sintering temperature on properties of TMCs like physical, mechanical, and structural. Titanium alloys are showing good mechanical and biomedical properties when reinforced with carbon fibers, borides, ceramics, and plenty of other materials as continuous fiber or discontinuous particulates and whiskers. In this paper, the applications of TMCs in aerospace, automobile, biomedical, and defense have been narrated. Besides all these favorable properties and applications, TMCs can’t be used extensively in the said applications because of their high cost and difficulty in machining, that discussed in this paper over various challenges of TMCs. The cost reduction can be done by making Ti - super alloys. In addition, there is a necessity for an effective cooling system during the machining of TMCs to enhance machinability and some of the effective methods which may enhance the machinability of TMCs were also discussed.

Synthesis and characterisation of natural ceramic reinforced Titanium Metal Matrix composite

ABSTRACT This research study reports the fabrication of Titanium Metal Matrix composite (MMC) reinforced with Silica by Powder Metallurgy route. The composite was studied for morphological, microstructural and mechanical properties using advanced characterisation techniques such as XRD, SEM, EDX, Vickers Hardness Test, Charpy Impact Test and Compression Test. The density of composite was evaluated by Archimedes’ principle. The analysis of experimental results demonstrated the influence of the reinforced silica on the physical characteristics of titanium MMC. This synthesised composite showed porous and smooth surface with improved mechanical strength, hardness, and reduced density. The improved hardness could be attributed to the good interfacial bond formation between the titanium metal matrix and the SiO2 reinforcement in the composite.

Experimental Investigations on the Drilling of Titanium Metal Matrix Composite

Titanium Metal Matrix Composites have high specific strength and offer high stiffness compared with Nickel alloys and steel. While maintaining equivalent strength, it can reduce 50% weight relative to other super alloys. In this work, preparation of Silicon Carbide reinforced Titanium Metal Matrix Composite by powder metallurgy and drilling of the composite to evaluate the drilling forces are discussed and the effect of drilling process parameters on thrust force, surface finish and chip formation is studied.

Recent trends on titanium metal matrix composites: A review

Composites play a vital role in the modern industries to produce components for various applications due to their lower weight and excellent mechanical properties. In recent years, researchers developed different metal matrix composites (MMCs) to improve the properties of metal matrices. Metals like Titanium possess an excellent combination of features, but it lacks some properties like wear resistance, thermal conductivity, etc. Various reinforcement materials like ceramics, carbon elements, etc. with different sizes are dispersed into Titanium to eliminate the limitations. The reduction in the size of the reinforcement and the matrix-reinforcement interfacial reaction influences the properties of the composites. Although numerous fabrication methods are employed to produce Titanium MMCs, recently, Spark Plasma Sintering (SPS) and Additive Manufacturing (AM) processes are widely used to fabricate MMCs. This review concentrates on recent trends in the fabrication, reinforcements, and mechanical properties enhancement with the reinforcement characteristics.

Machining of Titanium Metal Matrix Composites: Progress Overview.

The TiC particles in titanium metal matrix composites (TiMMCs) make them difficult to machine. As a specific MMC, it is legitimate to wonder if the cutting mechanisms of TiMMCs are the same as or similar to those of MMCs. For this purpose, the tool wear mechanisms for turning, milling, and grinding are reviewed in this paper and compared with those for other MMCs. In addition, the chip formation and morphology, the material removal mechanism and surface quality are discussed for the different machining processes and examined thoroughly. Comparisons of the machining mechanisms between the TiMMCs and MMCs indicate that the findings for other MMCs should not be taken for granted for TiMMCs for the machining processes reviewed. The increase in cutting speed leads to a decrease in roughness value during grinding and an increase of the tool life during turning. Unconventional machining such as laser-assisted turning is effective to increase tool life. Under certain conditions, a “wear shield” was observed during the early stages of tool wear during turning, thereby increasing tool life considerably. The studies carried out on milling showed that the cutting parameters affecting surface roughness and tool wear are dependent on the tool material. The high temperatures and high shears that occur during machining lead to microstructural changes in the workpiece during grinding, and in the chips during turning. The adiabatic shear band (ASB) of the chips is the seat of the sub-grains’ formation. Finally, the cutting speed and lubrication influenced dust emission during turning but more studies are needed to validate this finding. For the milling or grinding, there are major areas to be considered for thoroughly understanding the machining behavior of TiMMCs (tool wear mechanisms, chip formation, dust emission, etc.).

Oxidation of Biocompatible Graphite–Ti Composite after Laser Ablation in Different Atmospheres

The field of biocompatible material surfaces is a widely researched topic. Surface energy, surface topography and surface chemistry are important properties of biocompatible surfaces. These properties contribute to better osseointegration and adhesion of cells to implant surfaces. This article investigates the chemical and phase composition of the surface of a new titanium composite produced by powder metallurgy. Surface oxidation of the graphite– titanium metal matrix composite (TiMMC) after laser beam micromachining (LBMM) is discussed in this paper. Laser micromachining was performed in an argon shielding atmosphere and air. The aim was to determine the influence of the shielding atmosphere and the input parameters of LBMM on the presence of oxygen on the surface. Laser-treated surfaces were examined with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The phase composition was analysed with X-ray diffraction (XRD). Experiments confirmed that an argon shielding atmosphere reduces surface oxidation. The oxidation was also affected by the energy of the laser beam acting on the material. The maximum amount of oxygen detected on the surface after LBMM in air and argon was 38.6 wt. % and 24.2 wt. %, respectively. The presence of TiO, TiO2 and Ti2O3 oxides were detected on the surface after laser ablation in air. In contrast, Ti2O3 and TiO oxides were detected after laser ablation in the argon shielding atmosphere.

Experimental Characterization of Tool Wear Morphology and Cutting Force Profile in Dry and Wet Turning of Titanium Metal Matrix Composites (Ti-MMCs)

Metal-matrix composites (MMCs) are made of non-metallic reinforcements in metal matrixes, which have excellent hardness, corrosion, and wear resistance. They are also lightweight and may pose a higher strength-to-weight ratio as compared to commercial titanium alloys. One of the MMCs with remarkable mechanical properties are titanium metal matrix composites (Ti-MMCs), which are considered a replacement for super-alloys in many industrial products and industries. Limited machining and machinability studies of Ti-MMCs were reported under different cutting and lubrication conditions. Tool wear morphology and life are among the main machinability attributes with limited attention. Therefore, this study presents the effects of cutting and lubrication conditions on wear morphology in carbide inserts when turning Ti-MMCs. To that end, maximum flank wear (VB) and cutting forces were recorded, and the wear morphologies within the initial period of the cut, as well as the worn condition, were studied under dry and wet conditions. Experimental results denoted that despite the lubrication mode used, abrasion, diffusion, and adhesion mechanisms were the main wear modes observed. Moreover, built-up layer (BUL) and built-up edge (BUE) were the main phenomena observed that increase the tendency of adhesion at higher cutting times.

Development of titanium metal matrix composites reinforced with coated powders

This paper evaluates the feasibility of using SiC and TiC as reinforcement particulates for titanium metal matrix composites (Ti-MMC). The SiC and TiC particles were coated with titanium using a chemical coating technology in order to achieve a homogeneous mixing when they were mixed with pristine Ti. The Ti-MMC with these specially prepared reinforcements were fabricated by a conventional press and sinter route. The effects of sintering temperature in Ti matrix were investigated with respect to phase constituents, microstructure and tribology properties. No in situ phases were observed during sintering and the reinforcement and matrix show sufficient bonding, which acts as a major parameter to enhance hardness and wear resistance compared to pure Ti. All the composite samples had a high sintered density. The hardness of the composites increased with an increase in the sintering temperature. It was also noticed that with the increase in the temperature ranging from [Formula: see text]C to [Formula: see text]C, improvement in the mechanical and tribological properties of the developed titanium matrix composites could be observed. The highest hardness value [Formula: see text] was recorded for Ti-2 wt.% Ti-coated SiC composite when sintered at [Formula: see text]C for 3 h.

Ultrafine and fine particle emission in turning titanium metal matrix composite (Ti-MMC)

Titanium metal matrix composite (Ti-MMC) has excellent features and capabilities which can be considered a potential candidate to replace commercial titanium and superalloys within an extensive range of products and industrial sectors. Regardless of the superior features in Ti-MMC, however, referring to several factors including high unit cost and existence of rigid and abrasive ceramic particles in the generated matrices of the work part, the Ti-MMC is grouped as extremely difficult to cut with a poor level of machinability. Furthermore, adequate process parameters for machining Ti-MMCs under several lubrication methods are rarely studied. Therefore, adequate knowledge of this regard is strongly demanded. Among machinability attributes, ultrafine particles (UFPs) and fine particles (FPs) have been selected as the main machinability attributes and the factors leading to minimized emission have been studied. According to experimental observations, despite the type of coating used, the use of higher levels of flow rate led to less UFPs, while no significant effects were observed on UFPs. Under similar cutting conditions, higher levels of FPs were recorded under the use of uncoated inserts. Moreover, cutting speed had no significant influence on UFPs; nevertheless, it significantly affects the FPs despite the type of insert used.

Recent Advances in the Design and Fabrication of Strong and Ductile (Tensile) Titanium Metal Matrix Composites

Titanium metal matrix composites (TiMMCs) offer much improved strength, elastic modulus, and wear resistance at both room and elevated temperatures but often at the expense of tensile ductility, which excludes them from most key engineering applications. Recent advances show that this long‐standing strength‐ductility dilemma can be controlled to a large extent by adopting novel design concepts based on powder metallurgy (PM). These include: 1) reinforcing the Ti matrix with a three‐dimensional (3D) network‐like architecture of TiB whiskers or nanowires; 2) the use of nanostructured carbon precursors (nanotubes, fibers, and graphene) to enable in situ formation of TiC reinforcements; and 3) the exploitation of “ductility‐detrimental” interstitial elements (O, N, H) for strengthening. On a laboratory scale, the fabricated TiMMCs all exhibit an excellent combination of tensile strength and elongation, comparable to, or even better than, solution‐treated and aged (STA) wrought Ti–6Al–4V. The mechanisms behind these novel developments are analyzed. New insights into the design and fabrication of stronger and more ductile (tensile) TiMMCs are offered.

The decomposition of Si3N4 in titanium and its effect on wear properties

The use of silicon nitride (Si3N4) particles as potential reinforcement for titanium metal matrix composites (Ti-MMCs) was evaluated. Si3N4/Ti composite samples were fabricated by a conventional press and sinter route. The effects of sintering temperature and the concentration of Si3N4 in Ti matrix were investigated with respect to phase constituents, microstructure and tribology properties. Si3N4 weight fraction inside the Ti matrix was found to be the key parameter determining phase constituents and overall properties even at lower concentrations. Because of its instability in Ti at higher temperatures, in situ reactions between the reinforcing particles and matrix led to the formation of phases such as Ti5Si3 and possibly Ti3Si, in the composites containing higher fractions of Si3N4. The formation of homogeneous Ti5Si3 phase resulted in excellent wear properties at the expense of ductility. The wear resistance was directly proportional to the weight fraction of Si3N4. The highest hardness value 949HV1 was recorded for Ti-5 wt% Si3N4 composite when sintered at 1300 °C for 3 h. This work will benefit in understanding these composites as a prospective wear resistant material in industrial applications.

Reinforcement size dependence of mechanical properties and strengthening mechanisms in diamond reinforced titanium metal matrix composites

Diamond particulates reinforced titanium matrix composites (TiMMCs) were fabricated by spark plasma sintering technique at different reinforcement sizes of 5, 100, 200 nm and 3 μm. The dependence of reinforcement size on the mechanical and tribological properties in the TiMMCs was studied, paying particular attention to the nanoscale effects. The enhancement in strength of the composites was elucidated on the basis of strengthening mechanisms characterized by load transfer, thermal mismatch, grain size, and Orowan strengthening. The strengthening mechanisms were quantitatively analyzed and evaluated as a function of particle size. The results revealed that the presence of 5 nm diamond particles enhance strength by interacting with dislocations, while simultaneously retarding grain growth. Although the micro-composite has a little higher strength than the nanodiamonds reinforced composite, the latter has a combination of high strength and high ductility as wells excellent tribological properties.

Tool wear characterization in high-speed milling of titanium metal matrix composites

Titanium metal matrix composites (Ti-MMCs) have been successfully incorporated into a vast number of products within various industrial sectors. Despite excellent mechanical and physical features, due to the presence of hard and abrasive ceramic particles in metal matrices of Ti-MMCs, various issues have been emerged regarding machining and machinability of Ti-MMCs. Among critical machinability attributes, tool/insert wear and surface quality, in principle average surface roughness, Ra, are the principal critical attributes. This study plans to present an experimental analysis of wear characterization of polycrystalline diamond (PCD) and carbide inserts during high-speed milling of Ti-MMCs. The main wear modes observed were adhesion, abrasion, and diffusion. Oxidation was also observed at under those cutting conditions with elevated temperature. Regardless of the insert used, edge chipping was also observed in milling tests under various levels of cutting. It was observed that cutting speed and depth of cut are the major cutting parameters affecting wear rate in carbide X500 and PCD inserts. Meanwhile, surface roughness Ra was not affected by the cutting parameters used when using PCD insert. Promising tool wear rates also were recorded under low levels of cutting speed and high levels of feed rate when using carbide insert X500.

A titanium composite with dual reinforcements of micrometer sized TiB and submicrometer sized Y2O3

It has been challenging to achieve good strength-ductility synergy in titanium metal matrix composites (Ti-MMCs). Herein we report a new Ti-MMC produced by multi-directional forging (MDF) undertaken in near β phase region. The developed composite exhibits a microstructure featuring dynamically recrystallized (DRX) ultrafine α-Ti matrix with uniformly dispersed micrometer sized TiB whiskers and submicrometer sized Y2O3 particles. This unique microstructure renders the composite an exceptionally high strength and good ductility at room temperature. The strengthening mechanism of the dually reinforced Ti composite is discussed.

Interdependencies between graphitization of carbon nanotubes and strengthening mechanisms in titanium matrix composites

Titanium (Ti) metal matrix composites (TMCs) reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated by powder metallurgy. Different concentrations (0.5 and 1.0 wt.%) of MWCNTs were dispersed into Ti powder by high energy ball milling (HEBM) and solution ball milling (SBM) processes. The solid-state interfacial reactions between dispersed MWCNTs and Ti matrices were controlled through altering the ball milling parameters and conditions. The powder mixtures were consolidated and sintered at 1100 °C in a vacuum furnace. The graphitization of MWCNTs and its strengthening efficiency in the fabricated TMCs were quantitatively characterized. The relationships between the graphitization and the key strengthening mechanisms were determined. The Ti-0.5 wt.% MWCNTs composites with in-situ TiC nanorods during HEBM and debundling of MWCNTs during SBM processes exhibited compressive yield strength of 882 and 920 MPA which demonstrated 18 and 32% increase compared to commercially pure titanium (CP-Ti), respectively. The key strengthening mechanisms included grain refinement, dispersion strengthening of homogenously dispersed MWCNTs and in-situ TiC particles, solid solution strengthening of carbon, oxygen and nitrogen in Ti matrix, and load-bearing strengthening in TMCs.

Molecular dynamics-based cohesive zone representation of Ti6Al4V/TiC composite interface

In this paper, Molecular Dynamics (MD) simulation is used to simulate the crack propagation along the interface of Ti6Al4V/TiC in Titanium metal matrix composites under Mode-I and II loadings and at different temperatures. MD simulation can then determine the interfacial traction-separation relationship between Ti6Al4V and TiC. The interatomic potential between the atoms in Ti6Al4V/TiC composite is defined by the second-nearest neighborhood modified embedded atom method (2NN MEAM) and the Morse potential. For Vanadium-Carbon (V-C) interatomic potential, the 2NN MEAM parameters are developed and validated based on previous first principle calculations conducted on VC structure. MD simulation results show asymmetrical crack propagation along the interface between Ti6Al4V/TiC and the crack propagates in Ti6Al4V than along the interface. The obtained traction-separation relationship is used to parametrize the cohesive zone model (CZM) for modeling the interface in finite element analysis. Validation of the parameterized relationship is done by finite element simulation of the compression test of Ti6Al4V/TiC at different volume fractions of TiC. A good agreement is shown between the stress-strain results obtained from simulation and the experimental data under the same conditions.

Turning titanium metal matrix composites (Ti-MMCs) with carbide and CBN inserts

Despite excellent mechanical and physical features of titanium metal matrix composite (Ti-MMC), hard and abrasive ceramic particles within the matrix structure, as well as high price, may lead to severe difficulties on machining and machinability of Ti-MMCs. Review of literature denotes that only limited studies are available on machining Ti-MMCs with commercial cutting tools under various cutting conditions and cutting tools/inserts. Furthermore, limited studies are available on machinability attributes of Ti-MMC under various cutting conditions used. Therefore, to remedy the lack of knowledge observed, this work intends to report turning Ti-MMCs with carbide, and cubic boron nitride (CBN) inserts under various cutting conditions. The mean values of surface roughness (Ra) and directional cutting forces, as well as flank wear (VB) were studied as the machinability attributes. The microstructural evaluations were conducted to discover the wear modes. Furthermore, the statistical tools were used to present the factors governing machining attributes studied. Adhesion, abrasion, and oxidation were observed as the principle wear modes on the flank sides of the tested inserts. According to experimental results and statistical analysis, the Ra and VB could be controlled by cutting parameters only when CBN inserts were used. Despite the inset used, factors governing both responses were not identical. Although average cutting forces were directly affected by cutting parameters used, however, the relatively low correlation of determination (R2) of directional cutting forces can be attributed to effects of cutting speed, elevated temperature in the cutting zone as well as rapid tool wear which are all correlated to others.

Dry and Semi-Dry Turning of Titanium Metal Matrix Composites (Ti-MMCs)

Metal matrix composites (MMCs) are composed of non-metallic reinforcements (i.e., ceramic) in metal matrices which feature high toughness, wear and fatigue resistant and relatively light-weight. One of the metallic composites with remarkable mechanical properties is titanium metal matrix composite (Ti-MMC) that is considered as an alternative to nickel-based alloys. Despite excellent mechanical and physical features of Ti-MMC, due to high price and presence of hard and abrasive ceramic particles in metal matrices, machining, and machinability of Ti-MMCs is a complex subject. Knowing that very limited studies are available on machining Ti-MMCs under various flow rates and lubrication modes, adequate knowledge about the effects of cutting parameters and lubrication modes on machining attributes is a critical issue. Therefore, this study intends to present the turning of Ti-MMC under dry and semi-dry modes at various levels of flow rates. Effects of cutting parameters on several machining attributes including cutting forces, surface roughness, and particle emission will be presented in the course of this study.

Analysis of the Microstructure and Mechanical Properties of Titanium-Based Composites Reinforced by Secondary Phases and B₄C Particles Produced via Direct Hot Pressing.

In the last decade, titanium metal matrix composites (TMCs) have received considerable attention thanks to their interesting properties as a consequence of the clear interface between the matrix and the reinforcing phases formed. In this work, TMCs with 30 vol % of B4C are consolidated by hot pressing. This technique is a powder metallurgy rapid process. Incorporation of the intermetallic to the matrix, 20 vol % (Ti-Al), is also evaluated. Here, the reinforcing phases formed by the reaction between the titanium matrix and the ceramic particles, as well as the intermetallic addition, promote substantial variations to the microstructure and to the properties of the fabricated composites. The influences of the starting materials and the consolidation temperature (900 °C and 1000 °C) are investigated. By X-ray diffraction, scanning and transmission electron microscopy analysis, the in-situ-formed phases in the matrix and the residual ceramic particles were studied. Furthermore, mechanical properties are studied through tensile and bending tests in addition to other properties, such as Young’s modulus, hardness, and densification of the composites. The results show the significant effect of temperature on the microstructure and on the mechanical properties from the same starting powder. Moreover, the Ti-Al addition causes variation in the interface between the reinforcement and the matrix, thereby affecting the behaviour of the TMCs produced at the same temperature.