Reinforced Titanium Matrix Composites Research Articles

Microstructural Characteristics of Ti‐Based Composites with Various Ceramic Reinforcements Manufactured via Hydrogen‐Assisted Blended Elemental Powder Metallurgy

Highly dense in situ reinforced titanium matrix composites are fabricated with hydrogen assisted two-stage press-and-sintering method as described in the article, number 2101689 by Yuchao Song, Tuo Cheng, Orest Ivasishin and co-workers. Type and size of starting ceramic additives have substantial impact on the microstructure formation, residual porosity, and hardness of the pre-sintered composites. Sintering of hydrogenated pre-alloyed powders at second processing stage ensures desirable microstructure, improved density and uniformity of composites.

Microstructure evolution and underlying thermal behavior of high-content TiC reinforced titanium matrix composites fabricated by laser directed energy deposition

Titanium matrix composites (TMCs) with high-content TiC have a wide prospect in the aerospace industry due to their high strength, hardness, and wear resistance. The comprehensive properties of TMCs are mainly determined by the morphology and distribution of TiC reinforcements. Hence, the effects of laser directed energy deposition (LDED) process parameters on the TiC morphology and the properties of TMCs were discussed in detail by simulations and experiments in this study. A finite element model was established by ANSYS APDL to explain the complicated phenomena during LDED of high-content TiC (60 wt%) reinforced Ti6Al4V composites. The effects of process parameters on the temperature field and grain solidification behavior were studied. As the scan speed increased, the maximum temperature gradient (G)·solidification rate (R) value increased from 6.2 × 103 to 1.4 × 104 °C/s, which caused the size of TiC to decrease gradually. The maximum G/R value decreased from 1285.5 to 491.9 °C·s/mm2, resulting in the morphology of TiC changing from dendritic to granular grains. 60 wt% TiC/Ti6Al4V composites free of pores and cracks were successfully fabricated by LDED. It was found that the TMCs were nearly dense (99.48%) with uniform dispersed TiC. Irregular-shape TiC particles were melted and then precipitated in the form of submicron lamellar and granular phases, which was consistent with simulations. At the optimized parameter, TMCs with an average hardness of 549.0 HV0.5 were obtained, and the wear resistance of this sample was improved by 53% compared to LDED-processed Ti6Al4V.

Formation mechanism of interdiffusion layer and mechanical properties of Al0.6CoCrFeNi high-entropy alloy/Ti composites

The 10 vol% Al0.6CoCrFeNi high entropy alloy (HEA) particles reinforced titanium matrix composites were fabricated successfully by hot pressing sintering under vacuum. The formation mechanism of interdiffusion layer and mechanical properties of the composites were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), back scattered electron (BSE), electron backscatter diffraction (EBSD) and compressive test. The results show that the interdiffusion layers composed of AlNi2Ti (BCC) and Ni-Ti mixed phases (FCC) are formed between the HEA particles and the matrix. The recrystallization mechanism of the composites is continuous dynamic recrystallization and second phase particle induced recrystallization. The concentration gradient and mixing enthalpy were the main driving force for the formation of phase in interdiffusion layer. The formation sequence of Ni-Ti mixed phases is NiTi2, NiTi and Ni3Ti. The compressive strength (1642 MPa) of the composites with the same strain (21.7%) is 86.1% higher than that of the pure titanium samples (882.5 MPa). During the compression process, cracking occurs at the Ni-Ti mixed phases interdiffusion layer.

Thermal conductivity and microstructure of graphite flakes reinforced titanium matrix composites fabricated by spark plasma sintering

In this study, pure titanium (Ti) and Ti-6Al-4 V (TC4) matrix composites reinforced with 50 vol% graphite flake (GF) were fabricated by spark plasma sintering (SPS) respectively. The effects of different matrix and sintering temperatures on the microstructure and thermal conductivity (λ) of the composites were systematically investigated. The results showed that the interfacial reaction between the GF and pure Ti or TC4 produced an intermediate layer of titanium carbide (TiC). The thickness of TiC layer in both composites increased with the sintering temperature. At the same sintering temperature, the thickness of interface reaction layer TiC in GF/TC4 composite was much lower than that in GF/Ti composite, which also made the λ of the former significantly higher than that of the latter. The best sintering temperature of the two composites was 1150 °C. Under this condition, the λ of 50 vol% GF/TC4 composite reached 185.03 W m−1 K−1, which is more than 25 times of the λ of the matrix. It is expected to solve the problem of low λ of Ti materials used in plate heat exchangers.

Spark plasma sintering of discontinuously reinforced titanium matrix composites: densification, microstructure and mechanical properties — a review

Spark plasma sintering of discontinuously reinforced titanium matrix composites: densification, microstructure and mechanical properties — a review

A low-cost and high-performance casted titanium matrix composite with Cr3C2 additions

A low-cost, high performance TiC reinforced titanium matrix composite was successfully fabricated using an in situ reaction casting method. The results showed that the morphology and distribution of TiC in the microstructure were the more important factors affecting the properties of composites. And due to the second phase strengthening of the TiC and the Cr element solid solution strengthening for titanium matrix, it provides exceptionally high strength and toughness (1034.5 MPa ultimate tensile strength and 9.0 % elongation) for titanium structural components and increases extremely high hardness (50.4HRC) for titanium wear-resistant components. This study provides additional options for the application of low-cost titanium components.

Fabrication and Wear Properties of TiB2 and TiC Hybrid Reinforced Titanium Matrix Composites Produced Through Powder Metallurgy

Fabrication and Wear Properties of TiB2 and TiC Hybrid Reinforced Titanium Matrix Composites Produced Through Powder Metallurgy

Preparation and Damage Study of CoCrFeNiMo0.2 High Entropy Alloy Reinforced Titanium Matrix Composites

Preparation and Damage Study of CoCrFeNiMo0.2 High Entropy Alloy Reinforced Titanium Matrix Composites

Microstructural Characteristics of Ti‐Based Composites with Various Ceramic Reinforcements Manufactured via Hydrogen‐Assisted Blended Elemental Powder Metallurgy

The manufacturing of in situ reinforced titanium matrix composites by the sintering of titanium hydride and ceramic powder blends is an attractive and cost‐efficient process. Herein, a novel two‐stage (double‐compaction/double‐sintering) hydrogen‐assisted powder approach is suggested to produce uniform highly dense Ti‐based composites reinforced with TiB, TiC, and dual TiC + TiB phase particles. In this approach, the hydrogenation and milling of presintered products enable the initial porous materials to transform into hydrogenated prealloyed (PA) powders of controlled sizes, and a second press‐and‐sinter process further converts the PA powders into nearly dense composite microstructures with evenly distributed fine reinforcements. The adverse effect of the raw reinforcing powder size on microstructure uniformity, porosity, and mechanical characteristics of the presintered in situ composites becomes negligible in final sintering stage. The reduction of the porosity and enhancement of the hardness indicate that the hydrogen‐assisted double‐compaction and double‐sintering blended elemental powder metallurgy (BEPM) + PA approach enables the low‐cost fabrication of Ti‐based composites with suitable mechanical characteristics.

Corrosion behavior of in situ-synthesized (TiC+TiB)/Ti composites by laser powder-bed fusion: Role of scan strategy

The in-situ TiC and TiB reinforced titanium matrix composites were fabricated by laser powder fusion (LPBF) of B4C/Ti powder mixture, and the influence of scan strategy on the microstructure morphologies and corrosion resistance in NaCl solution were also investigated. The experimental results reveal that anodic dissolution of titanium matrix is accelerated and thus facilitates the formation of the TiO2 passive layer on the surface of the LPBF-produced (TiC+TiB)/Ti composites owing to the in-situ TiC and TiB reinforcements acting as micro-cathode in NaCl aqueous solution. The island scan strategy tends to result in a net-shaped distribution of TiC and TiB reinforcements and pore defects, which causes the inhomogeneity of galvanic couples and resultant TiO2 passive layer. Fortunately, the scan strategies of XY+ 30° and XY+ 67° can alleviate the thermal accumulation and leads to the transformation of refinements distribution to radial-shaped arrangement, which favors for the homogeneity of galvanic couples and resultant TiO2 passive layer. Moreover, the scan strategy of XY+ 90° generates a refinement and increased volume fraction of reinforcements and micro-galvanic couples, which significantly facilitates the formation of a thicker and less-defective TiO2 passive layer, thus leading to better corrosion resistance with a larger value of Rf. Furthermore, the corrosion mechanism of LPBF-produced (TiC+TiB)/Ti composites has also been discussed in detail based on the Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy results.

Effect of heat treatment on the microstructure and properties of CoCrFeNiMo0.2 particles reinforced titanium matrix composites

In this paper, the influence of heat treatment process on the microstructure and properties of CoCrFeNiMo0.2/Ti composites was studied by heat treatment of the composites. The structure and composition of CoCrFeNiMo0.2/Ti composites were characterized by X-ray diffraction and optical microscope. The distribution of elements of the interface layer was explored by electron probe. The mechanical properties of the composites were analyzed by nano indentation experiment and hardness tester. The relationship between irregular particles and the thickness of the interface layer was studied. The results are as follows: when the heat treatment temperature is 770 °C, the morphology of the high entropy alloy does not change significantly. As the temperature rises to 830 °C, the shape of the particles deforms and the thickness of the diffusion layer increases significantly. With the increase of the heat treatment temperature, the Young’s modulus and hardness of the interface layer have increased. When the heat treatment temperature rises to 890 °C, the particles completely diffuse into the matrix. Overall, the distance of the particles from the inscribed circle and the thickness of the interface layer are positively correlated.

Effect of C addition on microstructure and mechanical properties of laser micro-alloying Ti–Al–V–C titanium matrix composites

Most research activities involving the in-situ synthesis of TiC reinforced titanium matrix composites (TMCs) using laser additive manufacturing (LAM) focus on Ti and C interactions; however, interactions between other elements within the same context remain unexplored. This work details the design of a novel laser processing experiment called the laser micro-alloying (LMA) for depositing the Ti–Al–V-xC (0 ≤ x ≤ 1.0, wt.%) alloys, which was then used to elucidate the solid solution relationships between C, Al, and V in various matrices and the effect of C on the TiC in-situ precipitation behavior. The effect of C addition on the matrix microstructure was also elucidated to determine the alloying mechanism. It was confirmed that the solid solubility of C in the matrix decreases as Al and V contents increase. The TiC precipitation increases with increasing C content in the Ti alloy matrix, while the TiC morphologies in the samples evolved from feathery to clavate, then dendritic. It was noted that 0.12 wt.% C addition in Ti–4Al–3V resulted in a significant decrease in prior β grain size and α laths’ width, while further increasing C content had a negligible effect. Also, solid solution strengthening of C and continuous precipitation of TiC increased the indentation hardness, elastic modulus, and yield strength, with the increase being most significant when the C content is 0.12 wt.%. The work will lay a foundation for designing optimized TMCs used for LAM and other laser processing techniques.

Achieving high performance in (NiTi2 + TiC)/Ti composites with network architecture via reaction interface design

For the development of discontinuously reinforced titanium matrix composites (DRTMCs), tailoring the reinforcement network distribution has demonstrated significant advantages in alleviating the conflict between strength and ductility. In the present work, network structured titanium matrix composites reinforced with feathery NiTi2 and TiC nanoparticles were successfully prepared via an in-situ processing strategy. The introduction of C and Ni into the Ti matrix was achieved by electroless nickel plating of graphene nanosheets (GNFs) and a short-time ball milling process. The investigations of microstructure revealed that the 3D network architecture gradually formed with the increase of the reinforcement content, and the in-situ generated feathery NiTi2 was tightly connected to the TiC nanoparticles and grown into the Ti matrix. However, when the nickel content is too high, the 3D network architecture was replaced by a large number of amorphous areas, thereby deteriorating the performance of the composites. The tensile tests showed that the as-rolled composites can reach a tensile strength of 994 MPa while maintaining an acceptable ductility (~10.5%). The findings highlight the importance of interfacial microstructure design, which is helpful for the development of high-performance titanium matrix composites.

Simultaneously improving the strength and ductility of the as-sintered (TiB+La2O3)/Ti composites by in-situ planting ultra-fine networks into the composite powder

This study creatively proposed a technique to effectively overcome the strength-ductility mismatch of the as-sintered titanium matrix composites by in-situ planting TiB nano-fibers and La2O3 nano-particles as ultra-fine networks into the composite powder. (TiB+La2O3)/Ti composites with excellent strength-ductility synergy were fabricated by hot pressing. The ultra-fine network eliminated the Widmanstatten microstructure and exerted a significantly fine-grain effect. Thus, the elongation of the as-sintered 1.2 vol.% (TiB+La2O3)/Ti composite was significantly improved from 2.2 to 10.8% compared with the matrix alloy, and the ultimate tensile strength was simultaneously enhanced to 1098.6 MPa. Meanwhile, the tensile strength of 2.4 vol.% (TiB+La2O3)/Ti reached 774.8 MPa at 600 °C, even superior to many wrought composites. The strength-ductility synergy effects were mainly attributed to the significant fine-grain effect and the synergistic effect between nano-reinforcements and soft matrix. This work opened up a new route for directly sintering nanoparticles reinforced titanium matrix composites components with promising comprehensive properties.

Effect of TiC content on the microstructure and mechanical properties of Ti-30Mo-xTiC composites

TiC reinforced titanium matrix composites are promising for advanced applications. In this study, the Ti-30Mo-xTiC composites with the TiC content of 0, 0.5, 2.5 and 5 wt% were prepared using a powder metallurgy method. The results showed that TiC in Ti-30Mo exhibited a stoichiometric ratio of Ti to C over 1:1, along with demonstrating a semi-coherent lattice relationship with the β-Ti matrix lattice. Further, the excess C element diffused from the TiC particles to the matrix at the interface with large solid solubility, thus, promoting the sintering densification. Compared with Ti-30Mo, the composites with TiC addition revealed much higher relative density. Increasing the TiC content could increase the matrix microhardness and elastic modulus, however, the ultimate tensile strength and elongation were decreased. The mechanical properties were improved owing to the cooperative effect of densification, TiC particle reinforcement, solid solution of Mo and C elements and semi-coherent interface. As a result, the Ti-30Mo-0.5TiC composite presented an excellent combination of properties: matrix microhardness of 294 HV0.3, ultimate tensile strength of 820 MPa, elongation of 6.5% and elastic modulus of 112 GPa.

Microstructure and properties of high entropy alloy reinforced titanium matrix composites

In this paper, CoCrFeNiMo 0.2 high entropy alloy (HEA) particles reinforced titanium matrix composites were prepared by hot pressing sintering in the vacuum. The microstructure and composition of the composites at 700 °C ~ 900 °C were studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). Also, the mechanical properties of the composites were studied by microhardness tester, nano-indentation and uniaxial compression experiment. The results show that the interface layer of different thicknesses is formed between the particles and the matrix in the composites under different sintering temperatures. At 700 °C ~ 850 °C, the mechanical properties of the composites increase with the increase of temperature, which is related to the diffusion of HEA particles and the formation of the interface layer. When the sintering temperature is 850 °C, the hardness is 402.6 HV, the yield strength is 928.2 MPa, and the compressive strength is 2032.6 MPa. However, the high entropy alloy particles have a greater degree of dissolution and diffusion at 900 °C, the strengthening effect of the particles is weakened, so the mechanical properties of the composites are correspondingly reduced. • High entropy alloy reinforced titanium matrix composites were prepared. • The composites has high compressive strength (2032.6 MPa), due to the strength and toughness of the HEA and good interfacial bonding. • Young's modulus of the interface layer is a transition between the matrix and the particles, and the interface layer has the greatest hardness. • Macro-micro mechanical properties of composites are compared through a hybrid computational model, in which is much close to the Reuss model.

Configuration of new fiber-like structure driven high matching of strength-ductility in TiB reinforced titanium matrix composites

To fulfill the combination of high strength and ductility, configuration of novel fiber-like structural TiB reinforced titanium matrix composites was designed and successfully fabricated through series of powder metallurgy and hot working process. The influence of the fiber-like structure and microstructures on the mechanical response is investigated to clarify their strengthening and plasticizing mechanisms. Smaller equiaxed α-Ti grains generated in both the composites region and Ti region of the TiB/Ti composites. The new configuration improved the tensile strength from 573.5 MPa to 659.1 MPa while the ductility (24.4%) was comparable with that of pure Ti (23.5%). Besides, prismatic <a> slips with Schmid factors above 0.4 had higher distribution in both the composites region and Ti region of the TiB/Ti composites than pure Ti along the loading direction, suggesting the higher deformation ability of the TiB/Ti composites. Moreover, the loading-unloading-reloading (LUR) true stress-strain curves showed much higher back stress in fiber-like structural TiB/Ti composites compared with unreinforced Ti during deformation. The existence of the back stress increased the strain hardening rate when the true strain was above 0.05 and strengthened the Ti region, which was caused by deformation incompatible between the composites region and Ti region during tensile loading in the TiB/Ti composites. The higher mechanical response of the TiB/Ti composites is attributed to the introduction of TiB reinforcements with the new fiber-like structure, and the coupling effect of consequent grain refinement, load transferring effect, dislocation pinning effect of the fine TiB particles, back stress strengthening and the higher Schmid factors of prismatic<a> slips. • Novel fiber-like structure was designed to match the high strength and ductility in TMCs. • Configuration design of high strength composites without losing ductility by tailoring the spatial distribution of reinforcements. • The ductility of the composites was maintained for the higher Schmid factor values of prismatic<a> system and back stress. • Grain refinement, load transferring effect and back stress strengthening result to the strength improvement.

Three dimensional shape model of TiBw mesh reinforced titanium matrix composites in rotary ultrasonic grinding

TiBw mesh reinforced titanium matrix composites have excellent mechanical properties and high temperature properties, which have a wide application prospect in aerospace and other fields. However, the material processing has the characteristics of poor surface quality and unstable processing. In order to solve these problems, Rotary ultrasonic grinding was carried out on machining titanium matrix composites in this paper. A surface topography model for rotary ultrasonic face grinding of titanium matrix composites was analyzed, in which the effects of the shape of the cut section of the abrasive grain, the plastic deformation of the material, and whiskers were considered to analyze the formation mechanism of the surface of titanium matrix composites machined by rotary ultrasonic machining. The reliability of the model is verified by comparing the simulated topography with the actual topography through grinding experiments.

Preparation and Damage Study of High Entropy Alloy Reinforced Titanium Matrix Composites

Preparation and Damage Study of High Entropy Alloy Reinforced Titanium Matrix Composites

Graphene-Tib Hybrid Reinforced Titanium Matrix Composites with 3d Network Architecture: Fabrication, Microstructure and Mechanical Properties

Graphene-Tib Hybrid Reinforced Titanium Matrix Composites with 3d Network Architecture: Fabrication, Microstructure and Mechanical Properties