Reinforced Titanium Composites Research Articles

The corrosion behavior of graphene reinforced titanium matrix composites in 3.5 wt% NaCl solution

Graphene is widely preferred as a reinforcement element to enhance mostly mechanical properties of titanium matrix composites due to its unique properties. However, the number of detailed studies is quite limited in the literature on the corrosion properties of graphene reinforced titanium composites. Therefore, the effects of graphene amount on the corrosion properties of titanium composites were evaluated in this study. Pure titanium and graphene‑titanium composites for various amount of graphene (0.15, 0.30 and 0.45 wt%) were produced by powder metallurgy. The electrochemical impedance spectroscopy was used to analyze the corrosion properties of the samples in 3.5 wt% NaCl solution. From the results, TiGr15 sample was observed as maximum corrosion resistance with 6.6939 × 10+5 (Ω·cm2). The cyclic potentiodynamic polarization method results showed that TiGr15 sample (0.0007 mA/cm2) has the lowest corrosion flow rate. Moreover, the SEM-EDX images of the corroded samples showed that the highest cohesion of constituent particles and the least amount of corrosion, particle separation were observed at Ti-0.15 wt% graphene.

Tribological and neutron radiation properties of boron nitride nanotubes reinforced titanium composites under lunar environment

Tribological and neutron radiation properties of boron nitride nanotubes reinforced titanium composites under lunar environment

Structural-Temporal Peculiarities of Dynamic Deformation of Layered Materials.

The temporal nature of static and dynamic deformation of fibre metal laminates is discussed here. The aim of the study is to verify the proposed innovate model using layered composites. The modified relaxation model is based on the earlier formulated plasticity relaxation model for homogeneous materials. The proposed relaxation model makes it possible to describe the deformation of the layered composites from elastic to irreversible deformation, finalised by the failure moment. The developed approach allows us to consider the effects of the transition from static to dynamic loading. This means that the model-calculated dynamic limiting characteristics of the metal and the strength of brittle materials will have a determining character, depending on the loading history. The verification of the model using a glass fibre reinforced aluminium composite, glass fibre reinforced titanium composite, carbon fibre reinforced aluminium composite, and Kevlar fibre reinforced aluminium composite with different thickness ratios between metal and polymer layers is given. It is shown that the theoretical deformation curves of the metal composites at the various strain rates, finalised by brittle fracture of the polymer layers or continued irreversible deformation of remaining unbroken metal layers with destroyed polymer (fibre/epoxy) layers, are predicted. Based on the same structural−temporal parameters for five (Ti/GFRP (0/90)/Ti/GFRP(90/0)/Ti) and three (Ti/GFRP(0/90/90/0)/Ti) layers glass fibre reinforced titanium composites and the polymer layers, one-stage and two-stage stress drops during the irreversible deformation of the composite under static and dynamic loading are simulated. The change of the multi-stage fracture of the composite from static to dynamic loading and the fracture characteristic times of the polymer (100 s and 15,400 s) and the metal (8.4 ms) are correlated. Continued plastic deformation of the composite after fracture of the polymer layers is related with different values of the characteristic relaxation times of the polymer (fibre/epoxy) and the metal layers.

Graphene-TiC hybrid reinforced titanium matrix composites with 3D network architecture: Fabrication, microstructure and mechanical properties

Graphene (GR) was selected as a reinforcing phase to strengthen Ti6Al4V (TC4) alloy with incorporation of TiC nanoparticles at the interface of GR/Ti to reduce the interfacial reaction. The GR/TiC-TC4 composites with 3D-network architecture were fabricated by 3D dynamic mixing and spark plasma sintering (SPS) techniques. Experimental results showed that GR can be mostly preserved in the composites due to the inhibiting effect of the added nano-TiC at the GR/TC4 interface. The tensile properties of GR-TC4 and nano-TiC/GR-TC4 composites were improved with the increase of GR content. At the same GR content, the mechanical properties of the nano-TiC/GR-TC4 are higher than that of the GR-TC4 composites. The 0.05 wt% nano-TiC/0.3 wt% GR-TC4 composites showed the best combination of tensile strength and ductility. It was attributed to the synergistic enhancement of the GR/nano-submicron TiC by increasing the energy required for the microcrack propagation and deflection. The addition of nano-TiC can reduce the interface reaction of the GR/Ti and subsequently improve the mechanical properties of the GR reinforced titanium composites.

Mechanical, Wear and Thermal Behaviors of Graphene Reinforced Titanium Composites

In this study, the effects of graphene content (0.15, 0.30, 0.45 and 0.60 wt%) on the mechanical, tribological and thermal properties of titanium matrix composites were investigated. The experimental results showed that the highest ultimate compressive strength (845 MPa), tensile strength (613 MPa), lowest mass loss (0.6 mg for 10 N), and lowest wear rate (WR = 286 × 10−5 mm3/Nm for10 N) were obtained for Ti-0.15GNPs compared with pure titanium (652 MPa, 413 MPa, 1 mg and 5 × 10−5 mm3/Nm, respectively). The wear rate of composites deteriorates with increasing applied load. From the thermal analysis results, the best thermal conductivity (16 W/mK) and diffusivity (7.1 mm2/s) were performed for Ti-0.30GNPs composites at room temperature. The thermal behavior of the composites was decreased with increasing graphene content and temperature. It concluded that graphene is an effective reinforcement to develop the mechanical, wear and thermal behavior of titanium matrix composites.

Mechanical and wear properties of Si3N4 reinforced titanium composites

In the present study, Si3N4 reinforced titanium composites were produced by powder metallurgy method. The effect of various percentages of Si3N4 (0-9 wt.%) on the microstructure, density, hardness and compressive strength of titanium (Ti) composites have been investigated. After sintering at 1100oC for 120 min., the mechanical properties were significantly developed up to 3 wt.% Si3N4. The highest hardness and the greatest compressive strength were obtained for 3 wt.% Si3N4 reinforced composites (698.5 HV and 1093 MPa) when compared to pure titanium (414.2 HV and 826 MPa). Si3N4 addition developed the wear properties of composites when compared pure titanium. The lowest wear rate (1.36x10-5, 2.75x10-5 and 5.15x10-5 mm3/Nm for 10 N, 20 N and 30 N) were obtained for 3 wt.% Si3N4 reinforced titanium composite. The scanning electron image, elemental mapping and line analyses confirm the uniform distribution of Si3N4 powder in Ti matrix. Above this ratio, the properties of composites were deteriorated due to agglomeration tendency of Si3N4 powder. There were no in-situ formed second phases of composite structure from the X-ray diffraction analyses.

Face centered cubic titanium in high pressure torsion processed carbon nanotubes reinforced titanium composites

Carbon nanotube reinforced titanium (CNT/Ti) composites with high tensile strength (872 ± 5 MPa) were synthesized by the high pressure torsion process (HPT). Cs-corrected high resolution transmission electron microscopy (TEM) revealed face centered cubic titanium (FCC–Ti) distributed in the grains and at the grain boundaries of a hexagonal close packed titanium (HCP–Ti) matrix, with an orientation relationship of [0002]HCP//[111¯]FCC and {21¯1¯0}HCP//{011}FCC between FCC-Ti and HCP-Ti. The phase transformation from a HCP-Ti structure to a FCC-Ti structure in the CNT/Ti composites during the HPT process made a significant impact on the mechanical properties. Combining experimental results with density functional theory calculations, the stability of FCC-Ti and HCP-Ti under external pressure were analyzed. Moreover, the nucleation and growth mechanisms of FCC-Ti phase in HCP-Ti matrix were identified. The results showed that the stress-induced phase transformation from HCP-Ti to FCC-Ti in the CNT/Ti composites during the HPT process is associated with the source of Shockley partial dislocations. This work helps to the better understanding of the phase transformation mechanism from a HCP-Ti structure to a FCC-Ti structure in CNT/Ti composites.

Grafen-Titanyum (<30μm) Kompozitlerin Toz Metalurjisi Yöntemiyle Üretilmesi: Mikroyapi ve Mekanik Özellikler

Titanium has the most useful properties of the metal are corrosion resistance strength-to-density ratio, the highest of any metallic element. In its unalloyed condition, titanium is as strong as some steels but less dense. Due to its good features titanium can be used in the composite as a matrix material. Titanium matrix composites (TiMCs) can be used in various industries such as automotive, airplanes and especially biomaterials. Today, as carbon reinforcing material carbon nanotube (CNT), graphite and graphene are used as reinforcing materials. The graphene has the most remarkable properties in this reinforced material due to its extraordinary mechanical features, low friction and high abrasion resistance. Composite materials produced by using titanium and graphene may have remarkable mechanical and microstructural properties. This is conspicuous subject in recent years. In the present study, graphene (Gr) reinforced titanium composites were produced by powder metallurgy method. The effect of various percentages of graphene (0-0,15-0,30-0,45-0,60 wt.%) on the microstructure, density, hardness and compressive strength of Ti composites have been investigated. From the mechanical tests after sintering at 1100oC for 120min. The highest hardness and the greatest compressive strength were obtained for 0,30 wt.% Gr reinforced composites (520.2 HV and 1137 MPa) when compared to pure titanium (419.8 HV and 780 MPa). The crystal phase and microstructure of the composites were detected by scanning electron microscopy (SEM) and X-ray diffractometer (XRD). Better mechanical properties were observed for Ti-Gr composite materials when compared pure Ti. These kinds of composites promise the future for using especially the field of biomaterials.

Effect of process parameters on hardness and microstructure of graphene reinforced titanium composites

In this study, the effect of the sintering time, temperature and graphene amount on titanium properties was examined for the first time in detail. From the results, the highly dense (4.39 g/cm3), most hard (from 390 HV to 566 HV) and improved microstructure for 0.15 wt% graphene addition were performed at 1100℃ for 120 min. The titanium composite properties have been reduced with increasing graphene due to damaged graphene and titanium carbide formation above 0.30 wt% graphene. To summarise, when pure titanium is compared with graphene reinforced titanium composites, the properties enhanced due to dislocation and fine grain strengthening mechanisms.

Ti/B<sub>4</sub>C Composites Prepared by <i>In Situ</i> Reaction Using Inductive Hot Pressing

In the present work, in situ reinforced titanium composites (TMCs) synthesized using inductive hot pressing (iHP) are studied. The effects of B4C phases and applied processing conditions, on the microstructure and properties of TMCs, are investigated. With the addition of B4C particles, the microstructure of TMCs is refined and the strength is improved.Products of reactions which occur during the manufacturing process are analysed in detail. Microstructure observation illustrates, that B4C survives - depending on the processing conditions. The reinforcing phases are homogeneously distributed in Ti matrix. Moreover, results of densification, mechanical properties and hardness measurements help to identify the most suitable processing conditions to produce this kind of TMCs.

Influence of Sintering Temperature on the Microstructure and Mechanical Properties of In Situ Reinforced Titanium Composites by Inductive Hot Pressing.

This research is focused on the influence of processing temperature on titanium matrix composites reinforced through Ti, Al, and B4C reactions. In order to investigate the effect of Ti-Al based intermetallic compounds on the properties of the composites, aluminum powder was incorporated into the starting materials. In this way, in situ TixAly were expected to form as well as TiB and TiC. The specimens were fabricated by the powder metallurgy technique known as inductive hot pressing (iHP), using a temperature range between 900 °C and 1400 °C, at 40 MPa for 5 min. Raising the inductive hot pressing temperature may affect the microstructure and properties of the composites. Consequently, the variations of the reinforcing phases were investigated. X-ray diffraction, microstructural analysis, and mechanical properties (Young’s modulus and hardness) of the specimens were carried out to evaluate and determine the significant influence of the processing temperature on the behavior of the composites.

Titanium-niobium pentoxide composites for biomedical applications

The strength of titanium scaffolds with the introduction of high porosity decreases dramatically and may become inadequate for load bearing in biomedical applications. To simultaneously meet the requirements of biocompatibility, low elastic modulus and appropriate strength for orthopedic implant materials, it is highly desirable to develop new biocompatible titanium based materials with enhanced strength. In this study, we developed a niobium pentoxide (Nb2O5) reinforced titanium composite via powder metallurgy for biomedical applications. The strength of the Nb2O5 reinforced titanium composites (Ti-Nb2O5) is significantly higher than that of pure titanium. Cell culture results revealed that the Ti-Nb2O5 composite exhibits excellent biocompatibility and cell adhesion. Human osteoblast-like cells grew and spread healthily on the surface of the Ti-Nb2O5 composite. Our study demonstrated that Nb2O5 reinforced titanium composite is a promising implant material by virtue of its high mechanical strength and excellent biocompatibility.

624 放電プラズマ焼結法で作製した炭化物強化チタンの機械的特性の評価

624 放電プラズマ焼結法で作製した炭化物強化チタンの機械的特性の評価

Effect of Ti content and sintering temperature on the microstructures and mechanical properties of TiB reinforced titanium composites synthesized by SPS process

Titanium matrix composites reinforced with TiB whiskers have been synthesized using the spark plasma sintering method at temperatures between 950–1250°C. The influences of the Ti content of the initial mixtures and sintering temperature on the microstructure and mechanical properties of the TiB–Ti composites are investigated. The results indicate that the average size of the TiB whiskers increases significantly with an increase in Ti content of the initial mixtures. However, the TiB whiskers in the composites synthesized from the mixtures containing low content of Ti powders have a high tendency to agglomerate. Both bending strength and fracture toughness of the TiB–Ti composites increases with increasing Ti content of the initial mixtures. But bending strength increases slightly with increasing sintering temperature because of the simultaneous increase in the relative density of the composite and the average grain size of the TiB reinforcement. The results also suggest that hybrid-fracture characteristics appear in the fracture surface of the TiB–Ti composites synthesized in situ, which includes pull-out of the TiB reinforcement and the quasi-cleavage of the Ti matrix. Quasi-cleavage of the Ti matrix are the dominant fracture modes in the composites, and the volume fractions of pull-out of the TiB whiskers are relatively low.

Titanium processing: Current research and practical approaches

Over the past two years the titanium metal industry has been a focus for dynamic change and rapid growth. Driven by the large number of defense and commercial aerospace programs brought on by global economic growth and an aging fl eet, titanium supply was tight and prices high. The supply situation improved and prices declined as mill utilization ramped up and new titanium sponge production capacity came on-line. At the same time, delays in the introduction of major airframe projects and a slowing global economy eased supply concerns by stretching out delivery schedules. The aerospace industry continues to consume roughly half of all titanium and titanium alloy products currently produced, and order books continue to grow. This has been buoyed by the increased use of composite materials in new airframes, which demands an increased overall content of titanium in the structure. As much as the industry focuses on pricing and supply issues, a key to the development of more applications for titanium is processing. Low-cost titanium synthesis approaches are being developed and have been the subject of more than one TMS Titanium Committee-sponsored symposium. But even with the widespread availability of such material, processes that minimize waste, tooling, and energy consumption must be employed to extract the value in this amazing metal. This issue of JOM takes a look at current research and practical approaches in diverse application areas of titanium products. The following four articles span the size scale from tonnes of industrial mill products to grams of medical implants. We look at ways to reclaim and use lower-quality aerospace alloy material, and a novel process for making composite alloys that could fi nd application in the transportation industry. The fi rst paper, by R.D. Goin, focuses on industrial applications for titanium. Titanium or zirconium is often the material of choice for demanding corrosion conditions such as seawater desalination, power generation, or chemical processing. Cost issues can sometimes preclude their use, however, in favor of less corrosion-resistant alloys. Fusion welding of titanium to lower-cost stainless steels to create linings is not practical. Solid-state joining processes such as extrusion bonding and inertia welding can be used to fabricate bimetallic components, such as pipe and tubing, that provide a corrosion-resistant process interface with a lower-cost structural material to maximize value. The next paper, by M. Garcia de Cortazar et al., outlines research for making discontinuously reinforced titanium composites using master compounds produced by the self-propagating hightemperature synthesis approach. These compounds would enable the manufacture of chemically homogeneous titanium composite components using low-cost near-net-shape processes such as investment casting. This route avoids the isotropic property conditions sometimes seen with fi ber-wound continuously reinforced titanium-matrix composites. A range of compositions based on the addition of titanium diboride are shown, along with properties of trial castings. The paper by H. Guo et al. examines a powder sintering and forging approach on the microstructure and properties of Ti-10V-2Fe-3Al alloy. Often used as a structural alloy in aerospace applications, ingots of Ti-10-2-3 can be subject to a condition known as “beta fl eck” from chemical segregation of alloy elements that stabilize the beta phase. This condition can be cause for rejection of an ingot or component on quality grounds. This paper explores a route for processing Ti-10-2-3 with beta fl eck by employing the hydridedehydride process to break the bulk material down into a powder form. The powder is then blended and processed by a variety of standard powder metallurgy (PM) techniques and isothermal forging to full density. Mechanical properties are compared with values from the literature. Finally, we take a trip inside the human body to explore new designs and production of customized Ti-6Al-4V dental implants with the paper by G. Chahine et al. This is a fascinating approach whereby researchers are creating replicas of a patient’s actual tooth, root and all, in titanium from a computer-assisted design fi le using a net-shape electron beam fabrication technique. This, along with the ability to customize the structure of the implant for optimal anchoring and bone in-growth, points to an improved approach to dental implants that speeds healing, improves comfort, and can provide longer service life of the prosthesis. Productivity can be maximized at low overall cost by taking advantage of the capability to fabricate a large number of custom implants simultaneously.

Networking amorphous phase reinforced titanium composites which show tensile plasticity

Titanium matrix composites reinforced by an in situ formed networking amorphous phase have been prepared directly in the form of as-cast ingots. The composites show significant compressive and tensile plasticity. In contrast to the highly localized plasticity for most monolithic amorphous alloys, the tensile deformation of the current composites distributes uniformly over the entire specimen as a consequence of substantial work (strain) hardening. The formation mechanism of the networking structure, as a result of well-separated two-step solidification of the current alloy melts, have possible implications for composite synthesis in other alloy systems.

Development of New Low Cost Discontinuously Reinforced Titanium Composites for Commercial Applications

A new cost effective process to produce discontinuously reinforced (TiB) TMCs has been developed. The article presents general features of the composites, microstructural characteristics and mechanical properties. The production and characterization of two potential commercial applications are also discussed.

Titanium Carbide Particulate Reinforced Titanium Based Composite by In Situ Process

Titanium carbide particle reinforced titanium composites were prepared by in-situ synthesis reaction between titanium and carbon liquid alloys. The phases constitute and microstructures of titanium composite have been investigated by OM, XRD, SEM, EPMA and TEM. Although it was possible to synthesize titanium carbide particle reinforced titanium composites, the morphology of in-situ titanium carbide grows into typically dendritic shape due to the compositional supercooling theory. The observation of TEM also show that interfaces between the reinforcements and the titanium matrix alloy are very clean.

Fabrication and High Temperature Creep Behavior of In Situ Synthesized (TiB+TiC)/Ti Composites

In-situ 5 vol% TiB whiskers and TiC particulates reinforced titanium composites were fabricated by blending Ti powder and B 4 C particulates followed by reactive hot-pressing. The microstructure of the composites was investigated by using X-ray diffractometer (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). Two kinds of reinforcements with different shapes were formed during hot-pressing: TiB whisker and equiaxed TiC particle. The interfacial bonding between the reinforcements and titanium matrix is perfect. No interfacial reaction between reinforcements and Ti matrix was found. It can be seen from the tests of creep deformation that the creep rate of the composite is one order of magnitude lower than that of the pure Ti at 500'C.The activation energy of the unreinforced Ti and the composites are 228kJ/mol and 286kJ/mol, respectively.

Mechanical and Microstructural Properties of Titanium Matrix Composites Reinforced by TiN Particles

Particulate reinforced titanium composites were produced by PM route. Different volumetric percentages of TiN reinforcements were used, 5,10,15 vol%. Samples were uniaxially pressed and vacuum sintered at different temperatures between 1200-1300°C. Density, porosity, shrinkage, mechanical properties and microstructure were studied. Elastic properties and strength resistance were analysed by flexural strength and tension tests, and after the test, fractured samples were analysed as well to obtain the correlation between the fracture, interparticular or intraparticular, and the level of reinforcement addition. Hardness and microhardness test were done to obtain a better understanding of its mechanical properties. In order to study wear resistance pinon- disc tests were conducted. In addition, the influence of temperature, the reactivity between matrix and reinforcement on microstructural development were observed by optical and electron microscopy.