Ti TiC Research Articles

Synthesis of TiC–Ti Composites via Mechanical Alloying/Spark Plasma Sintering Using Ti and C Powders

Synthesis of TiC–Ti Composites via Mechanical Alloying/Spark Plasma Sintering Using Ti and C Powders

Enhancing the Thermal Conductivity of Laser Powder Bed Fusion AlSi20 by Introducing a Novel TiC–Ti Coated Diamond Powder

Enhancing the Thermal Conductivity of Laser Powder Bed Fusion AlSi20 by Introducing a Novel TiC–Ti Coated Diamond Powder

Study on microstructure and properties of laser-clad Fe-based (Ti, V)C composite coatings

An in-situ autogenous ceramic phase reinforced laser cladding containing vanadium (V) and titanium (Ti) has been developed for improving the surface properties of rolls in the field of iron and steel metallurgy. In this study, the effect of the V and Ti content on the microstructure, hardness, shear property, and wear behavior in high temperatures of the laser cladding was evaluated. The results showed that with the increase of the V and Ti content, TiC and VC precipitated with a growing volume in the grain and grain boundaries, and their shapes gradually changed from circle to polygon. In addition, the grain size was smaller and smaller while the microhardness was higher and higher. The precipitation of TiC and VC ceramic phase has a bad effect on the shear properties of the cladding layer due to the weak bonding strength between large-size carbide and matrix. The cladding layer with 5 % content of V and Ti showed better wear-resisting properties which are >21 times and twice higher than that without V and Ti at room temperature and 600 °C, respectively. Indicating that the size of the ceramic phase has the most important effect on the wear property because the ceramic particles with larger sizes were easy to dislodge and cause scratches to the specimen.

Effect of Ti and TiC additions on the microstructure and wear resistance of high chromium white irons produced by laser directed energy deposition

Laser directed energy deposition (L-DED) is an additive technology that offers a rapid solution for repairing mining components made of High Chromium White Iron (HCWI) on site. However, the refined carbide morphology from the rapid cooling in L-DED is detrimental to the wear resistance of the repairs. In this study, two types of powder (Ti powder and TiC powder) were added to improve the wear resistance of L-DED HCWI. The Ti powder addition promoted the formation of in-situ TiC while the TiC powder addition resulted in coarse ex-situ TiC and fine in-situ TiC in the as-deposited microstructure. The addition of both powders destabilised the austenitic matrix (γ-Fe). The wear resistance was investigated by a high stress abrasion test using silica sand (softer than M7C3) and a pin-on-disk wear test using a ruby pin (significantly harder than M7C3). The best wear results were achieved with 6.55 wt% Ti powder addition. This destabilised γ-Fe in the as-deposited microstructure which underwent strain-induced martensite formation during the high stress abrasion wear testing, improving the wear resistance of the alloy. The addition of TiC powder improved the wear resistance in the high stress abrasion test due to the increase in the fraction of carbide. In the pin-on-disk wear test, the alloys with TiC powder addition performed better than the cast sample because a greater amount of γ-Fe matrix in the microstructure provided a better combination of hardness and ductility.

Effect of HF etching on titanium carbide (Ti3C2Tx) microstructure and its capacitive properties

Two-dimensional multi-layered microstructure generated by hydrofluoric acid etching is essential for the high capacitance MXenes. However, the mechanisms dictating the formation, evolution and properties of MXenes during etching remain elusive due to the lack of direct observation. Herein, using ex-situ scanning electron microscopy combined with high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy, we have revealed the fine variation of microstructure and properties of multi-layered titanium carbide Ti3C2Tx etched for different time. The results show that the laminar cracks always formed from the first initial laminar crack at the edge site of the outermost side of the Ti3AlC2 particle, which induces continuous nucleation of other laminar cracks in the nearby area. The early laminar cracks undergo growth accompanying with increased macro-layer density of Ti3C2Tx and the Al(F,O,C)3 precipitation in subsequent etching process. The formation of laminar cracks is revealed to be correlated with the release of local internal stress in Ti3AlC2. In addition, it is found that there are significant changes of Ti valence state, CC and Ti-C bonding as well as Ti-F, CO and Al-O surface groups during etching. Maximum specific capacitance coincides with maximum lattice parameter c of Ti3C2Tx and maximum number of macro-layers, while over-etching produces in-plane microcracks, Ti dissolution, and reduced specific capacitance. The results provide important insight to facilitate optimal synthesis of this material.

Influence of the High-Voltage Discharge Treatment of Powders on the Properties of Metal Matrix Composites of the Ti–TiC System

Influence of the High-Voltage Discharge Treatment of Powders on the Properties of Metal Matrix Composites of the Ti–TiC System

Dry Sliding Friction and Wear Properties of Ti–TiC Composite Foams Prepared by Spark Plasma Sintering and Dissolution Process

Dry Sliding Friction and Wear Properties of Ti–TiC Composite Foams Prepared by Spark Plasma Sintering and Dissolution Process

Laser surface alloying of copper with Cr/Ti/CNT for enhancing surface properties

In this study, laser surface alloying of commercially pure copper (cp Cu) with Cr/Ti and Cr/Ti/CNT was conducted using a high-power diode laser. Cu–Ti intermetallic phases were detected in the Cu/Cr matrix of the laser-alloyed specimens without CNT. While TiC was found in the Cu/Cr matrix of the laser-alloyed layers with CNT. Compared to cp Cu (60 ± 10 HV0.2), the laser-alloyed specimens without and with CNT could achieve hardness up to 423 ± 12 HV0.2 and 860 ± 24 HV0.2 respectively. Sliding wear tests were also carried out at 60 km/h in dry condition with a pin-on-disc tribometer. Compared with cp Cu, the wear resistances of all laser-alloyed specimens were significantly improved due to solid solution alloying, existence of harder phases including Cr, Cu–Ti intermetallics and TiC. The wear resistance of the laser-alloyed specimens was increased up to a factor of 1220 times as compared with cp Cu. For the polarization study, the corrosion current densities of all laser-alloyed specimens (0.164–0.275 μA/cm2) in 3.5% NaCl solution at 25 °C were found to be lower than that of copper (3.362 μA/cm2) due to presence of passive Cr and Ti.

Optimizing phase interface of titanium carbide-reinforced copper matrix composites fabricated by electropulsing-assisted flash sintering

Full density TiC reinforced Cu matrix composites are fabricated by electropulsing-assisted flash sintering within 40 s. The addition of TiC significantly increases the hardness of the sintered sample. However, liquid Cu does not wet stoichiometric TiC, leading to a poor interface bonding strength between TiC and Cu, thus the tensile strength of the sintered sample is destroyed. By adding a small amount of Ti, the bonding strength of the interface between TiC and Cu can be effectively optimized, thereby the mechanical strength of the samples is improved, showing an increased hardness and tensile strength. Skillfully use the relationship between hardness and tensile strength curve to intuitively show the bonding strength of the micro interface from the macro characteristics. The reaction between dissolved Ti and stoichiometric TiC and the decomposition of stoichiometric TiC cause the formation of near-surface non-stoichiometric TiCx (x < 1) with a marked metal-like electronic structure, which is the fundamental reason for the optimization of the interface bonding between TiC particles and Cu matrix. In the process of powder metallurgy, it is a promising strategy to enhance the composite materials by adjusting the stoichiometry of ceramic to form metal-like electronic structure and alter the bonding strength of ceramic/metal interface.

Compaction of Composites, Dispersion- Strengthened by Nanoparticles, Based on Ti–TiC System with the Method of Spark Plasma Sintering

Compaction of Composites, Dispersion- Strengthened by Nanoparticles, Based on Ti–TiC System with the Method of Spark Plasma Sintering

Ti–TiC Composites by Thermal Explosion in Mechanically Activated Ti–xC Powder Blends (x = 1.0–6.3 wt %)

Ti–TiC Composites by Thermal Explosion in Mechanically Activated Ti–xC Powder Blends (x = 1.0–6.3 wt %)

High temperature sliding wear behavior and mechanisms of cold-sprayed Ti and Ti–TiC composite coatings

Ti and Ti-based alloys are used in many aerospace and automotive components due to their high strength-to-weight ratio and corrosion resistance. However, room and elevated temperature wear resistance remain an issue, thus requiring some form of secondary hard phase, e.g., refractory carbides, as well as solid lubrication to mitigate wear. In this study, cold spray Ti-xTiC (x = 14, 24 and 35 vol%) composite coatings were deposited on mild steel substrates with comparisons made to a baseline cold-sprayed Ti coating. The dry sliding friction and wear behavior were studied from 25 °C to 575 °C and during thermal cycling in this temperature range. While the room temperature friction coefficient of all the coatings remained relatively constant at ~0.5, the wear rate continually decreased from ~1 × 10−3 to ~2 × 10−5 mm3/N·m with increasing TiC loading. Raman spectroscopy measurements determined that the same TiO2 tribochemical phases (rutile and anatase) were present on the room temperature sliding wear surfaces, thus responsible for similar friction coefficients. With increasing sliding temperatures to 575 °C, the Ti–35%TiC composite coating exhibited the best overall tribological behavior, i.e., the friction coefficient decreased to ~0.3 along with a negative wear rate of −6.6 × 10−5 mm3/N·m (material gain on the wear track was recorded due to oxidation and transfer from the counterface). These friction and wear reductions were determined to be due to the formation of stable, low interfacial shear strength oxide glaze layers on the wear surfaces, composed of TiO2, WO3, and CoWO4 (transfer from WC-Co counterface). In addition, self-adaptive friction behavior was observed during thermal cycling as a result of the microstructural and tribochemical differences in the tribolayers.

Effect of the Method of Formation of Composite Ti–TiC Coatings on Their Composition, Microstructure, and Strength Properties

In the present work, the results of study of the composition, microstructure, and strength properties of composite coatings based on titanium and titanium carbide obtained using two different surface treatment methods—electric arc method in an electrolyte and laser method—are presented. It is shown that the coating parameters affecting the strength properties of samples, such as the morphology and size of carbide grains in the coating composition along with the coating thickness, are significantly easier to adjust using the laser cladding method.

Pulsed Discharge Preparation of a Modifier of Ti–TiC System and its Influence on the Structure and Properties of the Metal

It is shown that the addition of 0.01 wt.% of Ti–TiC modifier synthesized by the method of high-voltage electric discharge treatment of Ti powders in kerosene and briquetted with the help of spark plasma sintering makes it possible to reduce the grain size from 1–2 mm to 0.2–0.6 mm in all modified specimens of SM88U heat-resistant alloy. In this case, the tensile strength of modified specimens at a temperature of 900°С is 65–69 MPa and their long-term strength increases, on the average, by 20%.

Instability of in situ TiC particles in an Al-12Si alloy

This paper studied the evolution of in situ TiC particles in an Al-12Si alloy and the effect of Si on their stability. The samples were observed with scanning electron microscopy, and the phase analysis was performed by energy dispersive spectroscopy, X-ray diffraction, and transmission electron microscopy. The results demonstrated that Si can directly promote the evolution of TiC. After holding the TiC/Al-12Si alloy (TiC content of 2.75 wt.%) at 800 °C for 5 min, a large amount of TiC reacted with Al to form an Al4C3 phase and the Ti in TiC reacted with Al and Si to form a TiAlSi phase. When the holding time was increased to 20 min, the TiC almost completely disappeared. The morphology of TiC gradually changed from a regular tetra-decahedron to a sphere when Si was not added, and the average size gradually decreased from 1 μm and eventually disappeared completely. Si can diffuse into the TiC lattice to destroy its structure, thus forming a Si-rich disordered layer at the edge of the TiC particles. The values of diffusion resistance of Ti and C atoms in TiC, decrease owing to the destruction of the TiC lattice structure, which accelerates the TiC transformation reaction.

CNT‐induced TiC toughened Al2O3/Ti composites: Mechanical, electrical, and room‐temperature crack‐healing behaviors

AbstractThis study addressed novel multiphase composite of Al2O3/Ti/TiC that exhibited enhanced fracture toughness and room‐temperature crack‐healing function. Al2O3/Ti/TiC composites were fabricated through hot‐press sintering of CNT, TiH2, and Al2O3 mixed powders, where the TiC was in‐situ formed by reaction of CNT and Ti. The effects of CNT (TiC) content on mechanical and electrical properties were studied. Electrochemical anodization process at room temperature was attempted to these composites to heal cracks introduced in the surface of composites. Results indicated that added CNT was invisible while metal Ti and reaction product TiC coexisted in all samples. The reaction between CNT and Ti[O] representing dissolved active oxygen into Ti was considered as the main formation route of TiC. The toughening mechanism was demonstrated as crack deflection and bridging due to the presence of TiC. In spite of the increase in electrical resistivity because of the higher resistivity of TiC than Ti, the present Al2O3/Ti/TiC composites still remain high enough electrical conductivity (8.0 × 10−3 Ωcm ~1.8 × 10−2 Ωcm for 0‐2 vol% CNT addition) which could be regarded as conductors; it allowed to heal cracks in the composites by electrochemical anodization that formed titanium dioxide phase at room temperature. It was found that crack‐healing ability in 1 vol% CNT added composite exhibited higher strength recovery ratio of 95.6% to the crack‐free sample than that of Al2O3/Ti composite (the recovery ratio of 89.6%). After crack‐healing process, mechanical strength of samples increased by 52.3% compared to cracked composites. It was concluded that the formed TiC could contribute to the appropriate electrical conduction as well as interface strengthening in the Al2O3/Ti composites. Furthermore, it was firstly speculated that the TiC could be electrochemically anodized to form an oxide like Ti metal. These characteristics enable Al2O3/Ti/TiC composites as the crack‐healing materials at room temperature.

New method of obtaining heat-resistant biomorphic composites with carbide reinforcement

In this work, an original method of obtaining biomorphic composites of the Me – MeCx type, consisting of several stages, has been proposed. One of the steps is the Infiltration through Nonreactive Solvent (INS) method, which consists in converting biomorphic carbon preforms into porous microchannel MeCx ceramics by transferring a carbide-forming element to carbon through a solvent that does not react with carbon. The interaction of biomorphic alder-based carbon templates with melts of Cu – Ti and Sn – Ti systems has been investigated. It has been shown that as a result of the interaction of biocarbon templates with Cu-10Ti and Cu-20Ti alloys, carbon walls turn into TiC grains of micron and nanometer sizes, which partially repeat the template microstructure. The mechanism of formation of such a structure has been proposed. It has been demonstrated that, upon the interaction with Sn – Ti system, TiC and Ti2SnC layers are formed on the surface of the microchannels with good preservation of the initial template structure.

Ti and TiC co-toughened Al2O3 composites by in-situ synthesis from reaction of Ti and MWCNT

This study aims to toughen brittle Al2O3 ceramics by preparing Al2O3–Ti–TiC multi-phase composites from Al2O3, TiH2 and multi-walled carbon nanotube (MWCNT) mixed powders. Co-toughened effects of soft Ti phase and hard TiC phase which was in-situ formed by reaction of Ti and MWCNT were studied. For this purpose, Ti and MWCNT with different content were added into Al2O3 matrix to fabricate multi-phase composites of Al2O3–Ti–TiC and their microstructure, mechanical and electrical properties were investigated. Energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis indicated the successful synthesis of Al2O3–Ti–TiC multi-phase composites and the compositions were calculated by Rietveld method based on X-ray diffraction patterns. Due to the absence of MWCNT phase, the addition of MWCNT didn't improve electrical properties and these Al2O3–Ti–TiC multi-phase composites exhibited quite high electrical resistivity of ̴ 1011 Ωcm. On the other hand, the combination of Ti and TiC phases showed greater toughening effects than any single one. Fracture toughness of 0.5 vol% CNT added (Al2O3-2.4 vlo% Ti-7.9 vol% TiC) composite reached to the maximum which increased by 37% compared to monolithic Al2O3. The toughening mechanism was demonstrated as crack deflection and bridging by both Ti and TiC particles. In addition, it was found that when TiC which was in-situ formed from reactive Ti and MWCNT was employed to toughen Al2O3, owning to refined microstructure with nanosized matrix grains, formed Al2O3–TiC composite exhibited higher fracture toughness than that using direct TiC phase.

Microstructural evolution and abrasive resistance of WC7Co ceramic particle-reinforced Ti6Al4V composite coating prepared by pulse laser cladding

WC7Co/Ti6Al4V composite coatings are deposited on the pure Ti substrate by pulse laser cladding (LC). During the laser melting process, the decomposition of WC7Co particles will lead to the evolution of microstructure and phases, which is directly related to the wear resistance and mechanism of composite coating. The microstructural evolution, phase compositions and interface reaction of WC7Co/Ti6Al4V composite coating were examined by scanning electron microscopy, energy-dispersive spectrum and X-ray diffraction (XRD). The hardness of different structures and abrasive resistance of composite coating were measured. The results show that the typical microstructure of LC WC7Co/Ti6Al4V composite coating can be classified into dissolved WC7Co composite structure and un-dissolved WC7Co structure. According to XRD results, there are Ti solid solution, W, TiC, VC, Co3W3C and secondary W2C in composite coating. The eutectic structure formed by the dissolved WC7Co particles consisted of W, W2C, TiC and β-Ti solid solution. The mean hardness of different structures exhibits a significant gradient distribution in composite coating. A reaction layer composed of TiC, W and W2C is also generated onto the interface between un-dissolved WC7Co particles and Ti6Al4V alloy matrix. The abrasive mechanisms of WC7Co/Ti6Al4V composite coating are mainly adhesive wear and oxidation wear during the dry sliding process.

Effects of Doping of Composite Ti–TiC Coatings with Transition and Valve Metals on Their Structure and Mechanical Properties

This study presents the results of an examination of the mechanical properties and structure of wear-resistant composite Ti–TiC-based coatings, which were formed on commercially pure titanium by electric-arc processing in an aqueous electrolyte, with transition and valve metals (Al, Ni, Cr, and Si) introduced into their composition. This study demonstrated that the change in mechanical properties can be attributed to the formation of the martensitic phase at the titanium–TiC interface, which is induced by hardening phenomena associated with electric-arc processing.