Properties Of Titanium Matrix Composites Research Articles

Unique grain refinement mechanism of graphene oxide reinforced high-temperature titanium alloy matrix composite

Grain refinement is an effective way to improve the comprehensive mechanical properties of titanium matrix composites. In this work, the strong grain refinement effect of GO on 600 ℃ high-temperature titanium alloy prepared by hot isostatic pressing was found. The refinement mechanism was studied by experimental analysis, first-principles calculation and cellular automaton simulation. The α grain size of the composite with 0.50wt.% GO decreased by 53.2% compared with the matrix alloy. The direct effect of GO on grain refinement was weak. GO introduced C and O as α-stable elements to increase α phase content, resulting in the solid solubility of Si decreasing and fine (TiZr)6Si3 particles precipitating. (TiZr)6Si3 particles prevented dislocation from moving to accelerate continuous dynamic recrystallization nucleation and pinned grain boundary to inhibit grain growth. The results of cellular automaton simulation show that the inhibitory efficiency of (TiZr)6Si3 on grain growth was 4.7 times that of GO. The unique mechanism that GO promoted silicide particles precipitation and indirectly refined grain provided a design route for novel titanium matrix composites synergistically strengthened by two-dimensional nanosheets, in-situ nanoparticles and grain refinement.

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.

Effect of sintering temperature on the properties of titanium matrix composites reinforced with Al0·5CoCrFeNi high-entropy alloy particles

In this study, the organization and mechanical properties of the composites were analyzed at different sintering temperatures, and it was found that the local high-temperature phenomenon of discharge plasma sintering led to rapid melting and element diffusion at the junction of the high-entropy alloy particles and the Ti matrix, resulting in the formation of the interfacial layer. The increase in sintering temperature promoted close bonding between particles and element diffusion, caused lattice distortion and new phase formation, and increased the thickness of the interface layer and precipitated phase at the grain boundary. Most of the high-entropy alloy particles were dissolved when the sintering temperature reached 1050 °C. The composites were characterized by a high sintering temperature. The comprehensive mechanical properties of the composites first increased and then decreased when the sintering temperature increased, and they were optimized at 850 °C. The nanoindentation results show that the increase in sintering temperature leads to a decrease in the hardness of the high-entropy alloy particles, an increase in the hardness of the titanium matrix, and a higher hardness of the interfacial layer than that of the high-entropy alloy particles and the titanium matrix.

Microstructural evolution and mechanical properties of titanium matrix composites with second-phase dendritic TiC improved through B4C additions

Titanium matrix composites with high TiC content have multiple excellent properties. However, their dendritic TiC morphology poses challenges to their room-temperature plasticity. In this study, (TiC + TiB)-reinforced titanium matrix composites were developed by incorporating B4C into dendritic TiC composites. The impact of B4C additions on the microstructure evolution and mechanical properties of dendritic TiC in the composites was systematically investigated. The results revealed that the in-situ synthesis of TiC and TiB significantly refines the matrix grains of the composites with the addition of B4C. Notably, TiB serves as a nucleation substrate for dendritic TiC, forming an intergrowth microstructure of TiC and TiB during solidification–precipitation. This effectively reduces the number of dendritic TiC. The interfacial orientation relationships between TiC and TiB were studied through high-resolution transmission electron microscopy, revealing [110]TiC//[311]TiB and (111)TiC//(210)TiB, with a two-dimensional lattice mismatch of 6.43% between (111)TiC and (210)TiB. At room temperature, the ultimate tensile strength and fracture strain of the composite with 1 wt% B4C were 1059.52 MPa and 5.58%, respectively. Compared with the original composite, the tensile strength increased by 39.4%, and the corresponding elongation was remarkably increased. This enhancement is attributed to the synergistic strengthening effect and fine grain strengthening effect of the intergrowth structure of TiC and TiB in the composite. The microstructure refinement mechanism and strengthening mechanism are discussed in detail, providing new ideas and methods for the design and preparation of composites.

Enhanced properties of titanium matrix composites via in-situ synthesized TiCx and Ti5Si3 with network structure

In-situ network-structured (TiCx + Ti5Si3)/TC4 composites were fabricated via a low-energy ball mill and hot-pressing sintering based on the reaction between Ti3SiC2 and Ti. The microstructure evolution, mechanical properties, and tribological behavior of the composites with different amounts of Ti3SiC2 were studied. The experimental results show that the microstructure of the matrix transforms into the equiaxed structure with the addition of Ti3SiC2. The in-situ TiCx particles are mainly distributed around the matrix and form a network structure, as the Ti3SiC2 content is 5 vol%. Compared with neat TC4, the hardness, tensile strength, and wear resistance of the composites can be significantly enhanced. Moreover, the composite with 5 vol% Ti3SiC2 displays excellent comprehensive properties. The tensile strength of the composite is 1165 MPa, increased by 34.7 % over the neat TC4 and its elongation reaches 8.5 %. Meanwhile, the wear rate of the composite decreases to 24.5 × 10−5 mm3/(N·m), which is reduced by 16.7 % compared with the neat TC4. It is worth noting that the aggregation of particles can seriously reduce the mechanical properties of the composites.

Effects of carbon nanomaterials on interfacial structure and mechanical properties of high temperature Ti matrix composites

TiC is widely used as an ideal reinforcement to strengthen titanium matrix composites (TMCs). The morphology, size and distribution of TiC and the interfacial structure of TiC-Ti are crucial to obtain good mechanical properties of titanium matrix composites. These are keys to achieve superior strength and good ductility in titanium matrix composites. Hence, we investigated the effects of TiC generated in situ from different carbon sources (i.e., amorphous carbon nanoparticles, reduced graphene oxide and graphene nanoparticles) on the interfacial structure and mechanical properties of Ti60 alloy. Amorphous carbon nanoparticles (ACNS), reduced graphene oxide (rGO) and graphene nanoparticles (GNPs) reinforced Ti60 composites were prepared using spark plasma sintering (SPS). Among the three carbon nanomaterials, ACNs and rGO reacted with Ti60 matrix to form TiC, facilitating interfacial bonding. GNPs were not completely reacted with Ti60 matrix and residual on the interface owing to its poor dispersion effect, resulting in interfacial structure defects. The mechanical properties of the ACNs/Ti60 and rGO/Ti60 composites are high than GNPs/Ti60 composites. The ultimate tensile strengths of ACNs/Ti60 composites were 1173.49 MPa, 702.96 MPa and 653.13 MPa at room temperature, 600 °C and 650 °C, respectively, improving by 17.63%, 14.13% and 16.21% over Ti60, respectively. The superior mechanical properties are attributed to the fact that ACNs and rGO are more easily dispersed in the Ti60 matrix. The reaction activity of ACNs and rGO are higher than GNPs, and more TiC phase content was formed after sintering. TiC formed a semi-coherent interface with the Ti60 matrix, promoting the interfacial bonding strength. It also played a role in grain refinement and load transfer effect. This work helps to further elucidate the reinforcement effect of TiC formed by different carbon nanomaterials on TMC.

Spark plasma forging and network size effect on strength-ductility trade-off in graphene reinforced Ti6Al4V matrix nanocomposites

Architecting tightly bonded interface microstructure is the principal guarantee for increased mechanical properties of titanium matrix composites (TMCs). Adopting an effective technique to modulate interface structure is desirable to break through the trade-off of strength-ductility. Herein, a strategy is applied to establish interlocking interface in multilayer graphene (MLG) reinforced Ti6Al4V (TC4) matrix TMCs by spark plasma sintering (SPS) with subsequent spark plasma forging (SPF). By this technique, 3D network-structured composites of 0.35 wt% MLG/TC4 with tailored network size are fabricated via varied TC4 particle sizes (2–15 μm, 15–53 μm, 63–97 μm, 120–150 μm), then their microstructure and mechanical properties are explored systematically. Results depict that enhanced interface bonding and oriented configuration of reinforcements are generated in inhomogeneous network architecture with diminished internal defects by minimizing agglomerations after deformation, simultaneously enhancing the strength and ductility. Among the different network sizes, SPFed composite with 15–53 μm TC4 powder displays the better maintained tensile ductility (ε, 10.2%) with remarkably higher yield strength (YS, σ0.2) of 1089 MPa (27.52% higher than TC4), resulting in excellent strength–ductility synergy. Strengthening mechanisms and corresponding contributions are further discussed systematically. The work provides a valuable and facile pathway to prepare high-performance TMCs with outstanding interface microstructure.

Rapid in-situ synthesis, microstructure and mechanical properties of titanium matrix composites with micro/nano-sized TiB/TiC hybrid structures

Titanium matrix composites incorporating micro/nano-sized TiB/TiC hybrid structures were prepared utilizing the in-situ reaction of graphene/boron/titanium mixture powders by spark plasma sintering at 1100 °C for 5 min. Microstructural observation showed that the TiC micro/nano-scale particles homogeneously dispersed in the Ti matrix. Further observation revealed the TiC was polycrystal nanoparticles in the as-sintered bulk compacts. The uniform in-situ TiB whiskers formed by the boron/titanium reaction also exhibited the micro/nano-scale structure. The high hardness and compressive strengths, which increased by the more TiB fraction, were investigated through mechanical properties testing. The yield and ultimate compressive strengths of the composite (9.0 vol% reinforcements, TiB:TiC = 2:1) reached 1.86 and 2.18 GPa, respectively. This work represents an avenue to design and develop the homogeneous micro/nano-sized TiB/TiC hybrid structures, which were beneficial to mechanical response. The relevant strengthening mechanisms were discussed.

Microstructure, mechanical and thermal properties of titanium matrix composites with different reinforcements

In this study, three titanium matrix composites (TMCs) reinforced with graphite, graphene, and boron carbide (B4C) were fabricated through powder metallurgical techniques. The morphologies of grains and secondary phases of these TMCs were observed through Optical Micrograph (OM) and Scanning Electron Microscopy (SEM). The results of the mechanical properties of the TMCs showed that B4C was the most effective in increasing the strength and hardness, while the strengthening effect was comparable between graphite and graphene. The plasticity of the graphene reinforced TMC decreased sharply because of the formation of strip-like agglomerations. The small size, large volume fraction, and uniform distribution of the secondary phases contributed to the enhancement of strength and hardness in boron carbide reinforced TMC. Although the thermal properties of the TMCs were lower than pure titanium in the temperature range of 25 ∼ 300 °C, the thermal conductivities of the TMCs were all above 15.6W m−1·K.

Microstructure and Properties of Titanium Matrix Composites Synergistically Reinforced by Graphene Oxide and Alloying Elements

In this work, the microstructure and mechanical properties of titanium matrix composites were tuned by introducing graphene and alloying elements. The titanium matrix composites reinforced by graphene oxide (GO) and cobalt elements (GO@ Co/TA1) are synthesized by the spark plasma sintering (SPS) technique. Results show that the precipitated Ti2Co phase is almost reticulate distributed in the tissue, while the in situ TiC particles are discontinuously distributed at the grain boundaries. The ultimate tensile strength and yield strength of GO@ Co/TA1 composites are 160% and 126% higher than those of pure TA1, respectively. In addition, composites show excellent ductility where the elongation of GO@Co/TA1 is around 10.95%. Therefore, such enhanced mechanical properties can be attributed to the synergistic strengthening effect of interfacial‐distributed TiC particles and intragranular‐distributed intermetallic compounds (Ti2Co), which would provide a new idea for the design of metal matrix composite.

Room‐/High‐Temperature Mechanical Properties of Titanium Matrix Composites Reinforced with Discontinuous Carbon Fibers

The reinforcing effect of short carbon fibers (CFs) in Ti−6Al−4V (TC4) matrix composites fabricated by powder metallurgy is investigated by mechanical testing at room/high temperatures. Different mass fractions of CFs (0−3%) are dispersed into TC4 matrix by high‐energy ball milling. CFs/TC4 powder mixtures are then consolidated by hot isostatic pressing to obtain CFs/TC4 composites. Microscopic morphology, phase composition, and interfacial microstructure of CFs/TC4 composites are thoroughly characterized by various electron microscopies and Raman spectra. It is found that all composites fail before yielding at room‐temperature tensile tests, which is due to the unpleasant bonding condition between CFs and TC4. However, the 1% CFs/TC4 composite fractures in a ductile mode at elevated temperatures. The reinforcing effect of CFs becomes more prominent with the increase in testing temperature. At 700 °C, the 1% CFs/TC4 composite registers 74% improvement in the yield strength compared with the TC4 matrix, which suggests the excellent reinforcing effect of CFs among available reinforcements in the literature. The results suggest that short CFs might be a suitable reinforcement candidate for high‐temperature applications of titanium matrix composites.

The tribological behavior of different carbon nanomaterials-reinforced the titanium (TC21) matrix composite

This study examined the effects of different carbon nanomaterials on the mechanical and tribological properties of titanium matrix composites. Carbon nanotubes (CNTs), graphene nanoplates (GNPs) and graphene oxide nanoplates (GOs) reinforced Ti–6Al–2Sn–2Zr–3Mo–1Cr–2Nb–Si (TC21) titanium matrix composites were prepared by spark plasma sintering. In the three carbon nanomaterials, CNTs react with the TC21 matrix to form TiC, while GNPs and GOs react with the TC21 matrix to form a TiC coated GNPs/GOs sandwich structure, and the formation of TiC phase promotes the interfacial bonding of the composite. GOs/TC21 composites exhibit better strength and wear resistance than the other two composites. GOs/TC21 composite exhibits excellent mechanical properties, i.e., yield strength of 1043 MPa, the ultimate tensile strength of 1183 MPa and an elongation about of 8%. The wear loss of GOs/TC21 composite decreased by 24.2% compared to that of the TC21 alloy. The superior mechanical and tribological performances of GOs/TC21 composites are attributed to the TC21 matrix strengthening brought by the TiC particles/TiC coated GNPs/GOs sandwich structure and the lubricating properties of the residual GOs, which demonstrates that GOs is an ideal filler for TC21 alloy.

Micromechanical and tribological behavior of titanium matrix composites reinforced with graphene oxide

The micromechanical and tribological properties of titanium matrix composites reinforced with graphene oxide (GO) were investigated by nanoindentation and nanoscratch methods. The effect of sintering temperature on the nanohardness and elastic modulus of the composite was also evaluated. The results indicate that as the GO content and sintering temperature of the composite were increased, the nanohardness and elastic modulus significantly increased, attributing to the high mechanical property of GO and TiC formation. The composite reinforced with 5 wt% GO exhibited the maximum nanohardness (4.79 GPa) and elastic modulus (163.7 GPa) at 1473 K. At high temperatures, the composite achieved high elastic recovery. The nanoscratch behavior of the composites revealed that increased GO content and sintering temperature led to enhanced elastic recovery and reduced coefficient of friction.

Effects of heat treatment on interfacial characteristics and mechanical properties of titanium matrix composites reinforced with discontinuous carbon fibers

Weak interfacial bonding was a significant problem in titanium matrix composites (TMCs) reinforced with carbon fibers (CFs). In this study, heat treatment (HT) up to 1000 °C was applied on powder metallurgy Ti-6Al-4V matrix composites reinforced with discontinuous CFs to obtain different interfacial structures. Mechanical tests at both room-temperature and 500 °C showed that the best mechanical properties were attained at HT temperature of 900 °C. To understand the underlying mechanism, the phase structure, grain morphology and interfacial microstructure were examined. It was found that as HT temperature was increased, the interface thickness increases continuously and obvious grain growth happens at 1000 °C. Suitable interfacial reaction and fine grain size are identified as critical structural parameters to obtain high-performance CFs/TMCs. This study may provide new insight into the role of interfacial structure played in the strengthening effect of CFs/TMCs.

Tribology Properties of Titanium‐Based Metals Reinforced by BN Nanosheets

Herein, the tribology properties of titanium matrix composites (TMCs) are studied, which are formed by simply blending of aspherical Ti particles and BN nanosheets (BNNSs) using low‐energy ball milling and then spark plasma sintering. The mechanical properties of TMCs are characterized by nanoindentation tests, and their friction and wear properties are determined by ball‐on‐disc tests. The results show that the TMC with 0.1 vol% BNNSs (0.1‐TMC) content has the highest hardness and the ratio of hardness to elastic modulus (H/E). In addition, the lowest coefficient of friction (COF) and wear loss of 0.1‐TMC indicate the best tribological performance. Analysis of the worn morphology reveals that the pure Ti with the lowest H/E value presents several microcracks on the surface, implying the microcutting dominates wear process. The addition of BNNSs effectively inhibits the formation of microcracks, thus improves the tribological properties. However, as the content increase, the adhesion of BNNSs and Ti powder becomes worse, increasing the wear debris, leading to abrasive wear and adhesive wear and causing the even more severe wear. As a result, the COF and wear loss of 0.8‐TMC are the largest.

Precipitation behavior of silicide and synergetic strengthening mechanisms in TiB-reinforced high-temperature titanium matrix composites during multi-directional forging

To investigate the precipitation behavior of silicide and evaluate the contribution of the reinforcement phase to the properties of titanium matrix composites, a TiB-reinforced high-temperature titanium matrix composite was prepared by vacuum induction melting and multi-directional forging. The microstructure of the resultant composite after multi-directional forging was composed of a spheroidized α-phase, uniformly-distributed TiB and dual-scale silicides. The precipitation of silicides was attributed to the acceleration of elemental diffusion due to dislocations during forging. The strength of the composite after multi-directional forging at room temperature increased by about 151.9 MPa due to the fine-grain strengthening of the α-phase and the precipitation strengthening of the silicides, whereas the load-bearing efficiency of the TiB whiskers was reduced with the decrease in the aspect ratio. The strength of the multi-directional-forged titanium matrix composite at 700 °C was reduced by about 28.3 MPa. However, its plasticity was significantly improved, and the elongation reached 116.8%. The main reasons for the decrease in the strength were the easy initiation of cracks the grain boundaries and the weakening of the precipitation strengthening of the silicides.

Monitoring the neural network modelling of wear behaviour of Ti-6Al-4 V reinforced with nano B4C particle

The main objective of the study is to fabricate nano boron carbide (B 4 C) reinforced with titanium metal matrix composite (Ti-6Al-4 V) through powder metallurgy route. Composites preforms of Ti-6Al-4 V- (2–10) wt. % of nano boron carbide were fabricated. The characterization of the fabricated samples was preformed through Scanning electron microscope and X-Ray diffraction. Pin-on-disk wear testing machine was used to describe the lubricating wear behavior of the composites by varying loads and sliding distances. The surface morphology of worn out surfaces was also examined. Investigations over basic and functional properties of developed MMC revealed that the addition of nano B 4 C decrease the specific wear rate (SWR) and coefficient of friction (CoF). To predict the tribological properties of titanium matrix composites, Artificial Neural Network (ANN) technique was adopted to arrive at optimal values of the input parameters based on the experimental data. The results illustrated that the mathematical models of tribological properties of Ti-6Al-4 V-B 4 C are reliable with a less error and high level of accuracy.

Microstructure evolution mechanisms and strength improvement of (6.5 vol% TiC + 3.3 vol% Ti5Si3)/Ti6Al4V composites via heat treatments

To further improve the mechanical properties of titanium matrix composite containing relatively high fraction of TiC and Ti 5 Si 3 particles, (6.5 vol% TiC + 3.3 vol% Ti 5 Si 3 )/Ti6Al4V composites were prepared at different sintering temperatures, and then were carried out heat treatments. The microstructure evolution and corresponding mechanical behavior of composites were investigated. It found that the aggregation of particles in composite was reduced with the sintering temperature increasing, while the size of particles was increased. During the quenching process, the Ti5Si3 particles dissolved into matrix and TiC particle played the role of preventing the growth of matrix. TEM and EBSD analyses revealed that the size of Ti5Si3 particles increased (from 50 nm to 300 nm) with the aging temperature increasing (from 700 °C to 900 °C), and growth mechanism of matrix transformed from boundary migration to grain coalescence, leading to the abnormal growth of matrix. 1200 °C sintered composite had the compressive yield strength of 1780 MPa and compressive strain of 21%. After 1200 °C solution treating followed by 800 °C aging treating, the yield strength increased to 1900 MPa without obvious decline of ductility. The improvement was attributed to the strengthening effect of particles.

Microstructure and tribological properties of titanium matrix composites reinforced with in situ synthesized TiC particles

In this work, we prepared titanium matrix composites (TMCs) reinforced with in-situ polycarbosilane (PCS)-derived TiC particles. The effects of PCS addition on the microstructure, interface, hardness, and tribological properties were studied. The pyrolysis of PCS leads to the formation of in-situ TiC particles and Si solid-solution at a low PCS content (≤3 wt%). The TiC particles with a particle size of 4.8 μm are uniformly distributed in TMCs and have a well-bonded interface with the Ti matrix. The average grain size of α-Ti decreases from 100.5 μm in pure Ti to 16.1 μm in the Ti-3 wt% PCS composite. The presence of in situ synthesized TiC particles contributes to the excellent wear resistance of the Ti/PCS composites, which is ascribed to the increased hardness, superior load transfer capability, and oxidation wear resistance. The Ti-3 wt% PCS composite possesses the hardness of 4.72 GPa, elastic modulus of 169.23 GPa, and a low specific wear rate of 0.84 × 10−12 m3/(N·m) under constant conditions (3 N, 0.03 m/s). These values are all superior to those of Ti-6Al-4V alloy. This work sheds light on the design of high wear-resistant TMCs for industrial applications.

Thermal and mechanical properties of titanium matrix composites synthesized through solid state technique

Manufacture of Titanium Matrix Composites (TMCs) is highly concentrated in this research article. The pure titanium is included with graphite and boron carbide. The TMCs matrix of 90% of titanium powder, 7.5% boron Carbide Powder and 2.5% of graphite preferred in which titanium is matrix material. The composite produced via solid state powder metallurgy route. The synthesized specimens of titanium and TMCs (incorporated with boron carbide and graphite) produced via the processes of ball milling, compacting and sintering. The specimens included for microscopy examinations, hardness and compression investigations. The results presented and discussed in detail. The optical microstructure study confirms the homogeneous dissemination of reinforced particles in the matrix material. Thermal distribution and the thermal flux of the titanium alloy and the prepared composites were analyzed through ANSYS software. Manufactured composites are highly resistant on the temperature distribution compared to the base alloy.