TiB2 Research Articles

A Review on the Analysis of Thermal and Thermodynamic Aspects of Grain Refinement of Aluminum-Silicon-Based Alloys.

The present analysis addresses the solidification and thermodynamic parameters involved during the solidification of aluminum (Al)-based alloys as presented in the literature using different systems viz., binary aluminum-boron (Al-B) and aluminum-titanium (Al-Ti) systems, ternary aluminum-titanium-boron (Al-Ti-B) and aluminum-titanium-carbon (Al-Ti-C) systems, as well as taking into consideration the silicon-titanium-aluminide (Si-TiAl3) interaction in Al-based alloys containing Si. The analysis is supported by recent metallographic evidence obtained by the authors on A356.2 alloys. The sections on thermodynamic aspects cover the different models proposed concerning nucleation and growth on a newly formed Al grain. The value of the recalescence parameter reduces gradually with the increase in the Ti added. At a level of 0.20 wt%, this parameter becomes zero. If the concentration of grain refiner exceeds a certain amount, the grain size becomes minimal. Another parameter to be considered is the interaction between the grain refiner and traces of other metals in the base alloy. For example, Al-4%B can react with traces of Ti that may exist in the base alloy, leading to the reaction between boron and titanium to form titanium diboride (TiB2). Grain refinement is achieved primarily with TiB2 rather than aluminum diboride (AlB2), or both, depending on the Ti content in the given alloy.

Micro End Mill Capability Improvement Due to Processing by Fast Argon Atoms and Deposition of Wear-Resistant Coating

Micro-milling is widely used to make micro-channels in various fields. In this study, micro-milling of rectangular bronze microchannels was carried out with carbide end mills with a diameter of 1 mm, processed with fast argon atoms, and coated with anti-friction wear-resistant titanium diboride. It was shown that the removal of a 3 µm thick surface layer from a micro end mill with fast argon atoms makes it possible to reduce the cutting edge radius of the tool to 1.2 µm, which is three times lower than the minimum value of 4 µm achievable in mechanical manufacturing. The subsequent deposition of a 3 μm thick anti-friction coating results in a wear-resistant micro end mill with original geometric parameters but improved performance. The surface roughness of the machined bronze microchannel significantly decreased, and the burrs above the groove practically disappeared after micro-milling.

Protective Coatings Based on Titanium Diboride and Carbon Fillers

Protective Coatings Based on Titanium Diboride and Carbon Fillers

Influence of cow dung ash and TiB2 on the physicomechanical and tribological performance of Al6061-based hybrid composites

In order to fabricate a hybrid green metal-matrix composite, the present study investigated the effects of reinforcing a farm waste, cow dung ash (CDA), with hard ceramic titanium diboride (TiB2) of varying weight percentage ratios (0, 7.5:2.5, 5:5, 2.5:7.5 ratio). The physicomechanical and tribological performance were examined and noted that the tensile strength, hardness, and impact energy of the hybrid composites were enhanced with the incorporation of CDA and TiB2 reinforcements. Increasing CDA in hybrid composite reduced the density up to 4.12% and maximum increment in hardness and tensile strength was up to 28% and 24% respectively. The tribology test was conducted on a pin-on-disc tribometer at room temperature with varying loads (10 N–50 N), sliding velocities (0.52 m/s to 2.62 m/s), and sliding distances (500 m–1700 m). The wear loss and friction property of Al6061 has improved with reinforcement's addition and was found to be minimum at 2.5:7.5 (CDA: TiB2) weight percentages. The hybrid composites microstructure and worn surface profile are also associated with the observed tribological outcomes. The obtained results indicated that the S3 hybrid composite showed the best physicomechanical and tribological properties.

Effect of the addition of TiB2 with waste glass powder on microstructure, mechanical and physical behavior of PET-based polymer composite material

In present study, titanium diboride (TiB2) and glass powder waste utilized as reinforcement particles with Polyethylene terephthalate (PET) matrix material in development of a polymer-based composite. The % reinforcement of TiB2and glass powder waste varied from 2.5% to 20%. Micrographs of PET/8.75% TiB2/8.75% glass wastecomposite revealed uniform distribution of TiB2and glass powder in PET-based MMC. Proper wettability between matrix and reinforcement particles were observed for PET/8.75% TiB2/8.75% glass wastecomposite. Results showed that by adding 8.75% of TiB2and 8.75% of glass powder, mechanical properties of PET were improved.

Effects of soft and hard fillers on electromechanical properties and performance of polydimethylsiloxane elastomer for actuator applications

AbstractDesired ratio of relative permittivity and elastic modulus limits the application of silicone rubbers as flexible electromechanical actuators. The relative permittivity can be improved by incorporating varieties of high‐k (high dielectric constant) particles and polymer reagents as plasticizers and crosslinkers into elastomer matrix. The present work investigates the effect of polyethylene glycol (PEG) flakes, as a soft filler, and titanium diborides (TB) particles, as a hard filler, on electromechanical actuation performance of polydimethylsiloxane elastomer for soft actuator. Elastomer composites with various concentrations of fillers are prepared to compare the influences on optical, dielectric, and mechanical properties. Uniform dispersion of fillers is confirmed by field emission scanning electron microscopy, energy dispersive x‐ray spectrometer, and Fourier transform‐infrared spectroscopy analysis. Results show that the elastic modulus and relative permittivity are significantly influenced by filler contents. The elastic modulus increases with lower concentrations of PEG fillers, and at 8 wt%, it becomes comparable to the base material. Soft fillers aid in maintaining low elastic modulus, whereas hard fillers increase electrical breakdown strength as well as dielectric loss with almost equal changes in relative permittivity for both composites. The maximum actuation strain of 30.8% and 26.2% is attained for an in‐house fabricated linear actuator with 8 wt% of PEG and TB particles, respectively.

COLD UNIAXIAL PRESSING OF COMOSITE MATERIALS BASED ON PTFE WITH FUNCTIONAL ADDITIVES TIC AND TIB2

In the current work a solid-phase technology of composite materials based on polytetrafluoroethylene (PTFE) with functional additives is investigated. The mentioned additives are titanium carbides and diborides was obtained by self-propagating high-temperature synthesis (SHS). The process of pressing bulk density composite powders into compact blanks in a special mold by loading in a constant speed mode has been studied. Rheological strainstress curves were obtained. The time when a progressive increasing of stress inside the sample was determined. The results of these studies were compared with data for samples without additives (pure PTFE), as well as for compositions with basalt fiber. It is shown that at stresses 171-177 MPa it is possible to achieve a density corresponding to the calculated compact density of 2.24-2.25 g/cm3. The dependence of density variation over the volume of compact specimens has been studied, and a comparative analysis of the compressibility moduli G under uniaxial cold pressing has been carried out.

Significantly improved interfacial mechanical properties in boron nitride nanosheet/Ti composite via nano-configuration: A molecular dynamics study

Boron nitride nanosheets (BNNSs) reinforced titanium (Ti) matrix composites possess a combination of high strength and ductility due to the in-situ synthesized nano-configurations consisting of BNNSs, titanium boride (TiB) and titanium diboride (TiB2). The mechanisms for the outstanding properties, however, are yet fully unraveled. In this study, BNNSs/Ti composites with various nano-configurations are investigated by molecular dynamics (MD) simulation. Results show that the tensile strength and ductility of the composites increase with the number and length of titanium borides (TiBx). The excellent ductility is attributed to the crack-blocking and internal stress redistribution effects of the well-bonded TiBx nanophases. The strength enhancement mainly arises from the improved dislocation strengthening and load-transfer efficiency brought by the nano-interlocking structure. This work can benefit the optimization of BNNSs/Ti composites for fulfilling the strengthening and toughening potential of BNNS.

Simultaneously improved strength and ductility of low-cost Ti-Al-V-Fe alloy with TiB2 addition and thermomechanical processing

To obtain the low-cost titanium alloys with simultaneously improved strength and ductility by thermomechanical processing, 0.1 wt% of boron was added to the Ti-4Al-2.5V-1.5Fe alloy using titanium diboride (TiB2) as a boron source. The deformation mechanisms and microstructure evolution were systematically studied by comparative investigation of Ti-4Al-2.5V-1.5Fe alloys with and without boron. The results indicated that the addition of boride had a significant effect on the material parameters. Furthermore, TiB greatly improved the spheroidization and recrystallization of the alloy, and it can effectively limit grain growth during thermal exposure. Consequently, both high-temperature forging and further thermal deformation facilitated the generation and retention of the fine grain structure, dramatically improving the processibility of Ti alloys. For bare alloys, severe plastic deformation often leads to inhomogeneous microstructures and flow instability, which is harmful to mechanical integrity. In contrast, the addition of borides can significantly mitigate flow localization. In this study, boron-modified titanium alloys exhibited improved processibility and beneficial mechanical properties attributed to beneficial effects due to the addition of borides, which may enable new strategies for manufacturing high-strength titanium alloys in a more cost-effective way.

Electrochemical synthesis of Ti–B compounds from ionic-organic melts

The electrochemical synthesis of titanium borides from ionic-organic melts, based on carbamide, acetamide or imidazole, has been investigated by voltammetry and electrolysis. For better solubility of titanium and boron salts, we used salts containing ammonium as a cation: (NH4)2TiF6 and NH4BF4. Titanium boride coatings have been obtained on nickel and stainless steel by electrolysis from an ionic-organic melt at 120–135 °C. The X-ray phase analysis of samples after the electrolysis of the ionic-organic melt did not allow us to determine the composition of the coating because it was very fine-crystalline. In order to coarsen the crystal structure of the coating, the samples were annealed in a furnace at 600 °C in Ar stream. On the basis of XRD analyses, it may be assumed that the stoichiometry of the compound deposited from ionic-organic melts is TiB.

A facile route for the synthesis of high‐entropy transition carbides/borides at low temperatures

AbstractAs the main candidates in the field of ultra‐high temperature ceramics, high entropy carbides/borides (HECs/HEBs) have good oxidation resistance properties, high hardness, as well as excellent thermal and electrical conductivities, which are the focused points of research nowadays. In the current study, (Hf,Ta,Zr,Nb,Mo,Ti)C powders were successfully synthesized by a three‐step process, including the mixing process of raw oxides and carbon black with spaying Fe(NO3)3 solution, carbothermal reduction and subsequent calcium posttreatment. For the preparation of (Hf,Ta,Zr,Nb,Mo,Ti)B2 powders, during the calcium posttreatment process, equal stoichiometric ratio of B4C was added for the purpose of boriding reaction. The relevant X‐ray diffraction and SEM characterizations indicate the successful preparations of face‐centered cubic HECs and hexagonal HEBs. However, slight Mo local segregation was found in the prepared (Hf,Ta,Zr,Nb,Mo,Ti)B2 powders. The iron generated from Fe(NO3)3 promotes the solid solution process between monocarbides during the carbothermal reduction process via the dissolution‐diffusion‐precipitation mechanism. In the calcium posttreatment process, the liquid calcium ensures the boriding reaction take place at a low temperature. In addition, the residual carbon could be combined with calcium to generate CaC2 which is easy to be removed by acid leaching, and meanwhile, the added Fe could also be finally eliminated to produce pure HEC/HEB powders. The current method does not require the long‐time high energy ball milling of raw materials, but only simple and mild mixing is enough. Therefore, such a facile route has a great potential application prospect for industrially preparing high entropy phase powders in a large scale.

Near-Infrared Light-Responsive Multifunctional Photothermal/Photodynamic Titanium Diboride Nanocomposites for the Treatment of Antibiotic-Resistant Bacterial Infections.

Diseases caused by bacterial infection have resulted in serious harm to human health. It is crucial to develop a multifunctional antibiotic-independent antibacterial platform for combating drug-resistant bacteria. Herein, titanium diboride (TiB2) nanosheets integrated with quaternized chitosan (QCS) and indocyanine green (ICG) were successfully prepared as a synergetic photothermal/photodynamic antibacterial nanoplatform (TiB2-QCS-ICG). The TiB2-QCS-ICG nanocomposites exhibit effective photothermal conversion efficiency (24.92%) and excellent singlet oxygen (1O2) production capacity simultaneously under 808 nm near-infrared irradiation. QCS improved TiB2 stability and dispersion, while also enhancing adhesion to bacteria and further accelerating the destruction of bacteria by heat and 1O2. In vitro experiments indicated that TiB2-QCS-ICG had excellent antibacterial properties with an inhibition rate of 99.99% against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA), respectively. More importantly, in vivo studies revealed that the nanoplatform can effectively inhibit bacterial infection and accelerate wound healing. The effective wound healing rate in the TiB2-QCS-ICG treatment group was 99.6% which was much higher than control groups. Taken together, the as-developed TiB2-QCS-ICG nanocomposite provides more possibilities to develop metal borides for antibacterial infection applications.

Synergistic Effect of FSP and TiB2 on Mechanical and Tribological Behavior of AA2024 Surface Composites

Abstract In this research, AA2024 aluminum alloy-based surface composites were fabricated using ex situ titanium boride particles (TiB2) as reinforcement using the friction stir processing technique. Microstructural and mechanical variation with respect to the addition of TiB2 onto the AA2024 surface was studied and evaluated. Results proposed an increase in mechanical strength and hardness with respect to TiB2 addition when compared with the substrate metal. Dry sliding wear characteristics of aluminum surface composites at varying sliding distances (500 m, 1000 m, 1500 m, and 2000 m) were analyzed using pin on disc apparatus. Wear resistance of developed surface composites improved comparatively with respect to substrate metal due to the combined effect of particle inclusion and friction stir processing. Characterization of worn-out surface composites proposed that the wear mechanism happens due to the combination of abrasive and adhesive wear, while the major material removal happens due to abrasive wear.

Thermophysical properties of a Cu–Ti–C–B SHS composite

The paper studies the thermophysical properties of a Cu-Ti-C-B composite produced by self-propagating high-temperature synthesis (SHS) of an initial mixture of copper, titanium, boron carbide (B4C), and carbon powders. The matrix of the composite is a supersaturated solid solution of titanium in a copper lattice with Cu4Ti nanosized particles homogeneously precipitated under cooling. The matrix microhardness is 450 HV 0.1. Particles of titanium carbide (TiC) and titanium diboride (TiB2) resulting from SHS are randomly distributed in the bulk of the composite. The microhardness of the regions with the predominance of TiC particles is 640 HV 0.1, and the microhardness of the regions with the predominance of TiB2 particles is 900 HV 0.1. The average hardness of the composite is 60 HRC. Differential scanning calorimetry demonstrates a unified wide exothermic effect at temperatures ranging from 750 to 1000 °С, with an enthalpy of 148.6 J/g, associated with the exothermic reaction between residual titanium and boron carbide (B4C), which did not react during SHS. The temperature dependences of density, thermal diffusivity, heat capacity, thermal conductivity, and the coefficient of linear thermal expansion are experimentally determined. The particles of the strengthening phases are found to reduce slightly the thermal properties of the composite compared to pure copper. It is shown that annealing at temperatures of 800 and 860°C decreases the level of residual stresses in the composite matrix.

Mechanical and dielectric properties of Cissus Quadrangularis fiber-reinforced epoxy/TiB2 hybrid composites

Abstract This study focus on fabricating a Cissus Quadrangularis Fiber (CQF) reinforced epoxy hybrid composite with the addition of titanium diboride (TiB2) as filler. A compression molding technique was employed to fabricate the composite samples. The volume of the CQF was maintained at 30 wt%, and TiB2 was added with various weight proportions ranging from 0 % to 10 %. The mechanical, thermal, viscoelastic, and dielectric properties of the hybrid composite samples were evaluated. Scanning electron microscopy (SEM) was used to examine the impact of filler addition on the matrix-fiber bonding of the tensile fractured test specimens. The results revealed that the composite with 8 wt% filler produced high mechanical properties and comparable dielectric properties. Based on these findings, the fabricated composites are recommended for suitable applications in the automotive, electrical, and construction industries.

Mechanical, thermal, electrical, and corrosion properties of microwave-sintered Ti-0.8Ni-0.3Mo/TiB composites

In this study, Titanium boride (TiB) reinforced Ti-0.8Ni-0.3Mo/XTiB (X = 5, 10, 15, and 20 wt%) composites were successfully fabricated by microwave sintering assisted powder metallurgy process. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) and x-ray diffraction (XRD) analyses were used to evaluate the elemental powders individually. The distribution of TiB particles in the sintered Ti-0.8Ni-0.3Mo composites was observed using optical microscopy (OM) and SEM. The Microhardness of the microwave-sintered samples was evaluated through Micro Vicker’s hardness testing machine. Thermal characteristics were estimated for temperatures ranging from 50 to 250 °C. The electrical conductivity of Ti-0.8Ni-0.3Mo/TiB composites was calculated from the measured resistance values using the four-point probe method at room temperature. The immersion method was performed to estimate the corrosion properties by suspending the sintered samples in 3.5% NaCl solution for 60 h. The morphology of the corroded surfaces was examined using SEM. The results revealed that Ti-0.8Ni-0.3Mo/15TiB possessed optimum hardness values from 220 to 260 HV, mechanical properties such as True yield strength from 728 to 814 MPa, ultimate compression strength from 1335 to 1680 MPa, fracture strain of 6.12 to 13.81%. It also revealed less weight loss in a corrosion medium of 0.6 g. The Ti-0.8Ni-0.3Mo/TiB composites had good properties in densification aspects, which is suitable for applications such as marine and airfare components.

Coexistence of Electronic and Phononic Dirac Points in TiB2 Monolayer with Inverse Sandwich Motif

Although many Dirac semimetals (DSMs) have been theoretically proposed, the ideal Dirac fermions coexisting with Dirac phonons in a DSM are rare. In this work, we proposed a general strategy to assemble two-dimensional (2D) ideal DSMs using the cluster of transition metal boride with an inverse sandwich configuration. We illustrated this strategy using first-principles calculations, resulting in the creation of a 2D titanium diboride named 2c-TiB2 with a space group of P21/c. This monolayer was found to be thermodynamically, dynamically, and thermally stable. Additionally, it was revealed to be a DSM with an ideal Dirac cone at the Fermi level, and its topology arises from the band inversion between the pz orbitals of B atoms and dx2–y2 orbitals of Ti atoms. Furthermore, the monolayer exhibits intersecting Dirac phonons along high-symmetry path Γ–X. The quantized Berry phase, inversed eigenvalues, and apparent electronic and phononic topological edge states all served as further evidence of the topological protection originating from C2x symmetry. The theoretical investigation into inverse sandwich structured boride monolayer not only predicts the coexistence of Dirac fermions and Dirac phonons in 2D TiB2, but also provides a novel approach to design topological states in 2D nanomaterials.

Titanium boride fibers prepared by chloride-assisted carbothermic method for high-performance electromagnetic wave absorption

The TiB2 fibers were prepared by a chloride-assisted carbothermic method accompanied with the vapor-liquid-solid (VLS) mechanism. The influences of TiO2, B2O3, C12H22O11, and calcination temperature on the yield of TiB2 fibers were investigated. In addition, the effects of TiB2 fibers content on the electromagnetic (EM) parameters and microwave absorption (MA) properties of TiB2 fibers/paraffin composite was studied in detail. The TiB2 fibers/paraffin composite showed excellent microwave absorption performance, with an optimized reflection loss (RL) of −46.63 dB at 14 GHz and a thickness of 1.5 mm. Moreover, it exhibited a broad effective absorption bandwidth (EAB) (RL < −10 dB) of 3.9 GHz, ranging from 12 to 15.9 GHz. TiB2 fibers exhibit promising potential as materials for high-temperature applications in the field of MA.

Microstructure and mechanical properties of heat-treated cold spray additively manufactured titanium metal matrix composites

Cold spray additive manufacturing (CSAM) can produce particle-reinforced metal matrix composites (MMCs) by accelerating metal/metal or metal/ceramic particle combinations towards a substrate surface. The harder reinforcement particles become embedded into the softer metallic matrix. The secondary material may also help reduce the deposit's porosity depending on the particles' relative hardness and density. In this research, four material combinations were investigated by adding one of the following secondary materials at 10 wt% to commercial-purity (CP - Grade 2) titanium powder; (i) yttria-stabilised zirconia - (Y2O3)0.08(ZrO2)0.92, (ii) titanium carbide – TiC, (iii) titanium diboride – TiB2, and (iv) tungsten – W. The mechanical properties of samples following vacuum heat treatment are compared and related to the microstructural interactions between the two materials during annealing. These results show that cold spraying a hard secondary material at 10 wt% with titanium has a reinforcing effect, increasing the material's tensile strength; however, its ductility decreases slightly. The strengthening and ductility loss effect was particularly notable for the Ti blends with W and TiC.

Microstructure and mechanical properties of (Zr,Ti)B2–SiC composites obtained by pressureless sintering of ZrB2–SiC–TiO2 powder mixtures

Multiphase ceramics have been highlighted due to the combination of different properties. This work proposes to obtain the multiphase composite of (Zr,Ti)B2–SiC based on the mixture of ZrB2, SiC, and TiO2 sintered without pressure. The effect of TiO2 addition on solid solution formation with ZrB2, densification, microstructure, and mechanical properties was investigated. For this, 2.0 wt% TiO2 was added to ZrB2–SiC composites with 10–30 vol% SiC and processed by reactive pressureless sintering at 2050 °C with a 2 h holding time. Sinterability, crystalline phases, microstructure, Vickers hardness, and indentation fracture toughness of these composites were analyzed and compared to the non-doped ZrB2–SiC samples. The XRD analysis and EDS elemental map images indicated the incorporation of Ti atoms into the ZrB2 crystalline structure with solid solution generation of (Zr,Ti)B2. The addition of TiO2 resulted in matrix grain size refinement and a predominant intergranular fracture mode. The relative densities were not significantly modified with the TiO2 addition, though a higher weight loss was detected after the sample sintering process. The composites doped with TiO2 showed an increase in fracture toughness but exhibited a slightly lower Vickers hardness compared to composites without TiO2 addition.