TiC Composites Research Articles

Modeling of wear process parameters of in-situ RZ5-10wt%TiC Composite using artificial neural network

In this paper modeling of wear process parameters of in-situ RZ5-10wt%TiC metal matrix composite investigated. The RZ5-10wt%TiC composite has fabricated by argon assisted self-propagating high-temperature method. It is used in automotive, aerospace application to protect parts against wear. The pin on disc machine has used for the wear test. It has performed by varying input as the applied load and sliding distance. The coefficient of friction and weight loss considered as the output of the test. The results showed improvement in wear resistance of the RZ5-10 wt% TiC composite compares to the unreinforced alloy. Further, modelling of wear resistance of RZ5-10 wt% TiC composites were done using the back propagation neural network with Broyden–Fletcher–Goldfarb–Shanno(BFGS)algorithm. The ANN model trained using experimental data. After the completion of training process test data were used to check the system accuracy. It found success in the prediction of wear process parameters of RZ5-10wt%TiC composite. The results have shown that the values of wear process parameters obtained from ANN are very close to the experimental values. Also, it is useful compare to time-consuming experimental processes.

Influence of TiC addition on the surface roughness during turning of AA 7075 alloy processed through stir-casting

This research work had focused on manufacturing AA 7075/(0, 2.5, 5 and 7.5 wt%) TiC metal matrix composites through stir casting route. The manufactured composites had effectively characterized using the optical microscope. It had observed from the optical microstructures that the uniform distribution of TiC ceramic particles and its embedding over the ductile AA 7075 matrix had successfully obtained which exhibited excellent mechanical (218 HRC for 7.5 wt% TiC composite) and machining behavior with the function of TiC particles when compared to monolithic AA 7075 alloy. There had a grain refinement in the composites due to TiC particles addition. The machinability of experiments had conducted by varying the cutting speed, the feed rate, the depth of cut and the tool nose radius. The surface roughness had measured and the results had indicated that AA 7075–7.5 wt% TiC ex-situ composites had exhibited a lower value of surface roughness which had expected to high-strength in the matrix that produced immediate shearing action when compared to other samples. Further, the tool nose radius had played a major role in the surface roughness in which higher value of tool nose radius (0.8 mm) sample had shown improved surface finish.

The Influence of a TiN Film on the Electronic Contribution to the Thermal Conductivity of a TiC Film in a TiN-TiC Layer System

TiC and TiN films were deposited by reactive magnetron sputtering on Si substrates. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterization of the microstructure and interface structure have been carried out and the stoichiometric composition of TiC is determined. Thermal conductivity and interface thermal conductance between different layers in the films are evaluated by the transient thermo reflectance (TTR) and three-omega (3-ω) methods. The results showed that the thermal conductivity of the TiC films increased with temperature. The thermal conductivity of TiC in the absence of TiN is dominated by phonon contribution. The electronic contribution to the thermal conductivity of TiC in the presence of TiN is found to be more significant. The interface thermal conductance of the TiC/TiN interface is much larger than that of interfaces at Au/TiC, TiC/Si, or TiN/Si. The interface thermal conductance between TiC and TiN is reduced by the layer formed as a result of interdiffusion.

Dependency of annealing behaviour on grain size in Al–TiC composite produced by accumulative roll bonding

This work investigates the effect of grain size on annealing behaviour in both coarse-grained and ultrafine-grained Al–TiC composite processed by accumulative roll bonding (ARB). Microstructural analysis indicates that annealing behaviour of the specimens are essentially determined by the level of strain accumulation or number of ARB cycles, i.e., recrystallization phenomenon are accelerated by increasing the level of strain accumulation or number of ARB cycles. Microstructure analysis illustrates that annealing treatment at 200 or \(250{^{\circ }}\hbox {C}\) for the 1-cycle ARB-processed Al–TiC composite having coarse grains does not lead to the recrystallization phenomenon, indicating that only recovery appears. In contrast, partial recrystallization occurred after annealing at \(250{^{\circ }}\hbox {C}\) in the 7-cycle ARB-processed Al–TiC composite having ultrafine grains. Furthermore, annealing treatment significantly enhanced elongation for both ultrafine as well as coarse-grained Al–TiC composites in spite of the fact that yield and ultimate strength decreased during annealing treatment. The results proved that yield strength and tensile strengths for both 1-cycle and 7-cycle ARB-processed Al–TiC composites gradually decreased by annealing treatments between 200 and \(300{^{\circ }}\hbox {C}\). In contrast, ultimate elongation drastically improved by about 100% after annealing at the aforementioned conditions.

Combustion Synthesis of UHTC Composites from Ti–B4C Solid State Reaction with Addition of VIb Transition Metals

UHTC composites were prepared by self-propagating high-temperature synthesis (SHS) from the Ti–B4C reaction system with addition of Cr, Mo, and W. The starting sample composition was formulated as (3−x)Ti + B4C + xMe with x = 0.1–1.0 and Me = Cr, Mo, or W. For all samples conducted in this study, self-sustaining combustion was well established and propagated with a distinct reaction front. With no addition of Cr, Mo, or W, solid state combustion of the 3Ti + B4C sample featuring a combustion front temperature (Tc) of 1766 °C and a combustion wave velocity (Vf) of 16.5 mm/s was highly exothermic and produced an in situ composite of 2TiB2 + TiC. When Cr, Mo, or W was adopted to replace a portion of Ti, the reaction exothermicity was lowered, and hence, a significant decrease in Tc (from 1720 to 1390 °C) and Vf (from 16.1 to 3.9 mm/s) was observed. With addition of Cr, Mo, and W, the final products were CrB-, MoB-, and WB-added TiB2–TiC composites. The absence of CrB2, MoB2, and WB2 was attributed partly to the loss of boron from thermal decomposition of B4C and partly to lack of sufficient reaction time inherent to the SHS process.

PRODUCTION OF COMPOSITE CERAMIC MATERIAL FOR THERMAL SPRAYING

A composite ceramic material has been developed for thermal spraying that permits to increase wear resistance due to introduction of high-chromium steel and molybdenum in its structure, to obtain optimum porosity in the starting charge material while synthesizing FeCrMo – MoS 2 /CaF 2 /С – TiC compositions, to improve technological parameters of powders and thereby increase coefficient of powder usage in spraying, to reduce cost of wear-resistant coating technology. The paper presents characteristics and parameters of the developed material and coating which is based on it. Methodology is based on complex metallographical, X-ray diffraction and electron microscopy investigations of structural elements of composite plasma coatings. Main components of composite particles are solid solutions based on iron, titanium carbides, solid lubricant inclusions in the form of molybdenum disulfide, calcium fluoride, carbon. Presence of such powder particles predetermines obtaining wear-resistant coatings which are rather efficient in case of molecular and mechanical and abrasive wear-out under disadvantageous friction conditions (boundary lubrication or absence of lubrication material, elevated temperature actions). The contemplated powders are characterized by complex geometric shape and developed surface relief of particles. There has been observed a stable distribution of hard carbide phase in volumes of deposited materials and absence of superficial zone with deficit of TiC inclusions that positively influence on working capacity of the investigated wear-resistant coatings. Plasma coatings which have been deposited with the help of FeCrMo – MoS 2 – TiC powders in accordance with the technology developed by authors have better wear resistance in case of dry friction in a steel 45 (coating wear-out is less by 1.2-fold; scoring load is higher by 1.2-fold) than a coating which has been obtained with the help of Ni80Cr20 – 12 % MoS 2 – 50 % TiC powder. In such a case coating adhesive strength is increased by 1.23-fold and and powder cost lower is decreased by 1.5-fold. Thus plasma wear-resistant coatings obtained while using FeCrMo – MoS 2 /CaF 2 /carbon – TiC composite powders are considered as prospective for restoration and hardening of steel parts which are operating under disadvantageous friction conditions.

Formation of TiC x during reactive spark plasma sintering of mechanically milled Ti/carbon nanotube mixtures

Abstract In this study, powder mixtures of Ti with 5 and 10 wt% carbon nanotubes (CNT) were ball milled and subjected to spark plasma sintering (SPS) with an aim to prepare Ti-25 wt% TiC and Ti-50 wt% TiC composites. Changes in the powder particle size and the phase evolution were studied as a function of milling time. The effect of SPS temperature (800 °C, 1000 °C and 1200 °C) on the microstructure, phase evolution and the properties are presented. Reaction between Ti and CNT lead to formation of non-stoichiometric TiC x (x x was observed at 1200 °C temperature for the Ti-CNT mixtures. CHN measurements were carried out on the powder and the compact to study the source of additional carbon in the samples. Microstructural studies indicated that completely dense TiC x was produced at 1200 °C from Ti-CNT powders, while the milled Ti powders resulted in fully dense Ti-TiC x composite. The effect of C/Ti ratio on the lattice parameter of TiC x was studied. Mechanical properties were measured using Vickers microhardness and Nanoindentation.

Effect of addition of micron-sized TiC particles on mechanical properties of Si3N4 matrix composites

Abstract The effect of micron-sized TiC particles on mechanical properties of Si 3 N 4 matrix composites was investigated. Si 3 N 4 TiC composites were fabricated by using powder metallurgy and gas pressure sintering (GPS) methods. In order to achieve high mechanical properties, the experimental data were carried out with five different Si 3 N 4 TiC contents. Hardness, fracture toughness and relative density of Si 3 N 4 TiC composites were characterized. The result indicated that the highest relative density (98.0%) and fracture toughness (K IC = 8.4 MPa m 1/2 ) were measured for monolithic silicon nitride and 5 wt% TiC, respectively. Qualitative and quantitative phase compositions were analyzed by X-ray diffraction (XRD). The experimental analyses indicated that the TiC phase reacted with Si 3 N 4 during the liquid phase sintering, resulting in formation of TiC 0.3 N 0.7 . The phase transition, crystal growth, microstructure and mechanical properties of composites were investigated by scanning electron microscopy (SEM). Due to the inhibition of the grain growth, the aspect ratio exhibited a higher value from SNT0 (aspect ratio = 4.54) to SNT5 (aspect ratio = 5.60). The toughening mechanism of Si 3 N 4 TiC composites was attributed to crack deflection and crack impedance by periodic compressive stress in the Si 3 N 4 matrix. However, the increase of the TiC content easily led to excessive connection microcrack, which would not be beneficial for the strength.

Microstructure and mechanical behaviour of in situ fabricated AA6061–TiC metal matrix composites

AA6061–TiC composites were developed by in situ reaction of molten AA6061 alloy with potassium hexafluorotitanate salt and pure graphite at a temperature of 900°C. The in situ composites were subjected to hot forging at 500°C and uniform strain rate of 0.0115mms−1 with degree of deformation of 65%. Both cast and forged in situ composites were subjected to grain size analysis and scanning electron microscopy studies to study the dispersion of TiC particles. Mechanical properties like Brinell hardness and tensile properties were evaluated to measure the effect of TiC particles on the AA6061 matrix. Microstructure of forged composites revealed uniform dispersion of TiC particles without forming any lumps at any particular regions. Brinell hardness and tensile strength of cast and forged in situ composites increased with increasing TiC particle content. The improved mechanical properties were attributed to good dispersion of TiC particles, grain refinement of the matrix and dislocation strengthening. Every fracture developed in cast ones was due to inter-dendritic cracking while in the case of forged ones it had mixed mode of fracture with dominating ductile nature.

Reinforcements stimulated dynamic recrystallization behavior and tensile properties of extruded (TiB + TiC + La2O3)/Ti6Al4V composites

TiB, TiC and La2O3 multiple-reinforced Ti6Al4V matrix composites were successfully fabricated by common casting based on the in situ reaction of Ti, B4C, LaB6, and oxygen in the raw materials and forged subsequently. Hot extrusion was carried out on the as-forged composites to investigate its effect on microstructure and tensile properties of Ti6Al4V composites reinforced by low volume fraction of reinforcements. The microstructure showed that the TiBw and TiCp distributed homogeneously and the clustered reinforcements disappeared after hot extrusion. Besides, TiBw exhibited favorable alignment, rotating parallel to the extrusion direction and TiCp also distributed along the same direction. Moreover, the microstructure of as-extruded composites tended to formed two kind of microstructure zones: finer basket-weave zones containing few reinforcements, and equiaxial zones embedded with abundant reinforcements, which indicated that reinforcements stimulated dynamic recrystallization during hot extrusion. The tensile test results revealed that the hot extrusion can significantly improve the ductility of (TiB + TiC + La2O3)/Ti6Al4V composites accompanied by slight decrease of tensile strength, among which the 1.5 vol% (TiB + TiC + La2O3)/Ti6Al4V increased by nearly four times from 2.71% to 13.2% with ultimate strength decreasing by 8.5% from 954 MPa to 903 MPa, compared with that of the as-forged composites.

Optimisation of WEDM process parameters during machining of Cu-Ni-Si/TiC FGM using Taguchi's method

Functionally graded Cu11Ni4Si/10wt%TiC composite is fabricated using centrifugal casting and machined using wire-electrical discharge machine. The research objective is to find the optimal process parameter during machining and to study its influence on material removal rate (MRR) and surface roughness (Ra). The experiments were conducted on L9 orthogonal array by varying process parameters such as pulse on time (TON-115,120,125 µs), peak current (IP-100, 150, 200A) and wire feed rate (WF-2, 3, 4 mm/min). The trend of TON for MRR increased initially and then decreased, whereas for Ra, the trend is increasing. The relationship of IP and MRR initially decreased and then increased, whereas for Ra decreased steadily. The trend for WF was found to be linearly increasing for both MRR and Ra. Analysis of variance and S/N ratio revealed that the WF(98.19%) was the most significant parameter influencing MRR followed by TON and IP. TON(74.63%) was the most significant parameter influencing Ra followed by IP and WF.

相界面析出現象と最近の実用鉄鋼材料への応用

The interface-precipitation has been observed as row carbide arrange since 1960’s. Whereas the interface-precipitated carbides in steels were NbC, TiC, VC and Cr23C6 in the early stage, composite TiC containing Mo and W has been also become to observe recently. Several kinds of the mechanism of the interface-precipitation have been suggested and ledge mechanism and bowing mechanism which combined interface barging and carbide precipitation are widely accepted since the mechanisms successfully explained a large amount of the experimental results. Fine interface-precipitates in low carbon steel realize high strength steel sheets, plates, bars and rods which are non-quenched and tempered. Especially, in sheet products, in which fine carbides can be easily generated, ferritic steel of 1180 MPa in tensile strength is successfully obtained by dispersing fine carbides with the diameter of several nano-meters.

Rapid sintering and microstructure evolution of composite TiC cermet

Ti, Ni, activated carbon, and Mo powders were used as raw materials to prepare a composite TiC cermet in this study. The powders were mixed and prepared through high-energy ball milling and then sintered in a spark plasma sintering (SPS) system. Results revealed that ball milling time affected the raw materials. After ball milling was performed for 10 h, Ti and C particles reacted and generated TiC, meanwhile, the solid Mo solutionized in TiC and formed (Ti,Mo)C lumps. XRD results showed that the product of (Ti,Mo)C cermet with high hardness can be prepared at a low sintering temperature of 1150 °C. The microstructure of composite TiC cermet was different from the traditional core-ring structure. In particular, the developed microstructure comprises a (Ti,Mo)C-Ni dark-gray phase at the center surrounded by (Ti,Mo)C light-gray phase and dispersed Mo white phase.

Developing high toughness and strength Al/TiC composites using ice-templating and pressure infiltration

We prepared Al/TiC composites with different ceramic volume fractions (15, 25 and 35vol%) using ice-templating and pressure infiltration. The thickness of the lamellar layer and the porosity in the ceramic layer of the TiC scaffolds were controlled by varying the slurry concentration. The Al/15vol%TiC composite had a thick metal layer and a low-density ceramic layer, which effectively dissipated the stress at the crack tip and fractured in a multiple-crack-propagation mode, giving bending strength of 355±3MPa and fracture toughness of 81±2MPam1/2. However, the Al/25vol%TiC and Al/35vol%TiC composites had much higher bending strength (417−500MPa) but lower fracture toughness (46−33MPam1/2) as compared to the Al/15vol%TiC composite, and they fractured in a single-crack-propagation mode. In addition, an increase in the brittle TiAl3 phase with increasing ceramic volume at the fracture surface greatly deteriorated the toughness of the Al/TiC composites. Finally, the relationship between cracking mode and structure features in the laminated composites was discussed to account for the toughening mechanism.

Effect of heat treatment on the mechanical and microstructural characterization of Mg-AZ91E/TiC composites

Mg-AZ91E/TiCp composite was fabricated using a spontaneous infiltration technique at 950 °C under an argon atmosphere. The composites produced have 37 vol.% of metal matrix and 63 vol.% of TiC-like reinforcement. The obtained composites were subsequently solution heat-treated at 413 °C during 24 h, cold water quenched, and subsequently artificially aged at 168 and 216 °C during 16 h in an argon atmosphere. Effect of heat treatment on the microstructure and mechanical properties was evaluated. Microstructural characterization was analyzed using different techniques such as X-ray diffraction (XRD) and scanning electron microscopy (SEM). Interface between matrix and reinforcement was examined using transmission electron microscopy (TEM), and mechanical properties were evaluated by measuring the elastic modulus and hardness. Mg, TiC, Al, and Mg17Al12 phases through XRD were detected. Meanwhile, using TEM analysis in heat-treated composites MgAl2O4, MgO, and Al2O3 were identified. The as-fabricated composite have elastic modulus and hardness of 162 GPa and 316 Hv, respectively. After solution heat treatment and aging at 168 °C during 12 h, the composites reaches values of 178 GPa and 362 Hv for the elastic modulus and hardness, respectively. Time of aging was correlated with measures of elastic modulus and hardness.

Ultra high-pressure spark plasma sintered ZrC-Mo and ZrC-TiC composites

Ultra-high-pressure spark plasma sintering was applied to ZrC-20wt%Mo and ZrC-20wt%TiC composites with a pressure up to 7.8GPa and temperatures of 1550°C and 1950°C. Mechanical performance of the composites was benchmarked against a plain ZrC produced by the same method. Both composites outperformed the pure ZrC with superior hardness and indentation fracture toughness of 2239HV1 and 5.4MPam1/2, and 1896HV1 and 5.9MPam1/2, respectively, for ZrC-Mo and ZrC-TiC composites. It was shown that ultra-high compaction pressure affected the ZrC-20 wt%TiC miscibility gap by lowering the temperature threshold from the usually applied 1800°C down to 1550°C resulting in formation of the solid state solution of (Zr,Ti)C. In contrast, the high pressure does not inhibit the carburisation of Mo with ZrC to form MoC, even when experiments were performed in a graphite free environment. The equiaxed morphology of ZrC grains along with a right-shift in XRD peaks for ZrC indicates dissolution of Mo in ZrC resulting in formation of the solid solution of (Zr,Mo)C. High-temperature X-ray diffraction analysis under oxidation conditions was performed on the samples showing degradation of ZrC-20wt%Mo due to the oxidation of Mo at high-temperature leading to MoO3 vaporisation. Conversely, the oxidation of ZrC-20wt%TiC composites was characterised by formation of ZrO2 and TiO2 remaining stable up to 1500°C.

Effect of excess silicon content on the formation of nano-layered Ti3SiC2 ceramic via infiltration of TiC preforms

The aim of this work was to investigate the effect of silicon content on the formation and morphology of Ti3SiC2 based composite via infiltration of porous TiC preforms. The gelcasting process was used for fabrication of preforms. It was found that the infiltrated sample at 1500°C for 90min from a mixture of 3TiC/1.5Si containing 92wt.% Ti3SiC2. With the increasing of TiC and SiC impurity phases, Vickers hardness was increased to the maximum value of 12.9GPa in Ti3SiC2–39wt.%TiC composite. Microscopic observations showed that the Ti3SiC2 matrix was composed of columnar, platelike and equiaxial grains with respect to silicon content.

Refining effect of TiC on primary M7C3 in hypereutectic Fe[sbnd]Cr[sbnd]C harden-surface welding coating: Experimental research and first-principles calculation

Hypereutectic FeCrC coatings with and without Ti additive were developed by harden-surface welding. The equilibrium phase diagrams of the coatings were calculated by Thermal-calc software. The phase structures were determined by X-ray diffractometer (XRD). The microstructures were observed by optical microscopy (OM). The micro-morphologies of M7C3 and TiC were observed by field emission scanning electron microscopy (FESEM). The compositions of M7C3 and TiC were determined by energy dispersive spectrum (EDS). The crystal structure of primary M7C3 was determined by transmission electron microscopy (TEM). The phase diagrams indicate that TiC precipitates firstly in the coating with Ti additive. The subsequent phase transformation is the same as that in the coating without Ti additive, namely primary M7C3 precipitates and then eutectic reaction occurs. The XRD patterns are corresponding to the phase diagrams, which show that there exists TiC in the coating with Ti additive. By comparing their metallographic images, the primary M7C3 are obviously refined in the coating with Ti additive. From the micro-morphologies of M7C3 and TiC, it is found that TiC exists inside primary M7C3 and they are tightly combined. Therefore, TiC may be the heterogeneous nucleus of primary M7C3. On the basis of experimental research, the refining effect of TiC on primary M7C3 was investigated by first-principles calculation. The calculation results shows the work of adhesion of Fe3Cr4C3(0001)/TiC(111) interface is 3.48 J/m2 and the interfacial energy ranges from 0.921 J/m2 to 2.782 J/m2. The Fe3Cr4C3(0001)/TiC(111) interface is theoretically stable. The Fe3Cr4C3(0001)/TiC(111) interface is well jointed by TiC polar covalent/ionic bond and CrTi metallic bond. Therefore, the preferentially precipitated TiC in FeCrCTi alloy is the heterogeneous nucleus of primary M7C3 and thereby refines the primary M7C3.

A MIM Route for Producing Ti6Al4V-TiC Composites

Discontinuous reinforced titanium matrix composites have generated significant interest due to their compelling properties such as their specific strength and wear resistance at room and elevated temperatures. For these reasons, these materials have been considered in various applications such as automotive (valve components), aerospace (engine components) and medical devices (implants). Metal injection molding (MIM) has proven to be an efficient near net-shape technology suitable for high volume manufacturing of parts having complex geometries. The MIM technology is particularly attractive for producing composites as the metallic matrix does not go through the liquid state. This helps minimizing the segregation of the hard particles. MIM also reduces the needs for machining. However, the production of titanium components with the MIM process has its own challenges and limitations, such as presence of porosities and coarser microstructures compared to wrought products. The present work introduces the results obtained during the development of a MIM route for producing Ti6Al4V-5wt%TiC composites. The feedstock developed is wax-based and incorporates a pre-alloyed metal powder. The microstructure, mechanical properties at room and elevated temperatures, the wear resistance and the thermal diffusivity of the composites have been characterised. Properties are compared with those of a Ti6Al4V MIM material produced with the same feedstock and process but without TiC as well as with those of wrought Ti6Al4V reported in the literature. The presence of a small amount of TiC promotes densification and grain size refinement and affects the surface finish of the sintered components. Tensile properties of the composites are comparable or better than those of wrought Ti6Al4V (ASTM F1472). Improved mechanical properties compared to unreinforced material are associated to the higher density, finer grain size as well as solution strengthening of the titanium matrix.

In Situ Synthesis of Fe–TiC Nanocomposite Coating on CK45 Steel From Ilmenite Concentrate by Plasma-Spray Method

These days wear-resistant coatings including Fe–TiC composites because of their properties such as high melting point, hardness, and wear resistance are used in different fields such as aerospace, transport, cutting, and abrasive. In situ synthesis of Fe–TiC nanocomposite as a wear-resistant coating by the plasma-spray process is the purpose of this study. Ilmenite concentrate and carbon black were used as raw materials. Three kinds of powders with different conditions were prepared and sprayed on CK45 steel substrates in constant conditions. Microstructure, phase identification, wear resistance, and hardness of coated samples were determined. The results showed that activated sample was synthesized during the plasma spray, but in situ synthesize did not happen for inactive sample which was sprayed by plasma spray. Also, wear resistance and hardness tests showed by synthesis of Fe–TiC composite in coated samples, wear resistance, and hardness were increased.