TiC Reinforcement Research Articles

Deformation and fracture mechanisms of in situ synthesized TiC reinforced TC4 matrix composites produced by selective laser melting

In this study, TiC/TC4 composites were fabricated using selective laser melting (SLM), and the deformation mechanism and fracture characteristics of the composites with nano-sized TiC particles formed in situ were studied. The experimental results showed that the rapid melting and solidification characteristics of SLM and the Marangoni effect of the liquid pool promoted a considerably homogeneous dispersion of the in situ-formed nanoscale-TiC reinforcement in the TiC/TC4 composites. In particular, an enhanced compressive strength of 1490.2 MPa and a considerable fracture elongation of 21.5% were simultaneously achieved for the TiC/TC4 composites, which could be attributed to the load transfer effect and the formation of denser and more uniformly distributed dimples. Combined with the finite element (FE) analysis, the uneven stress distribution in the shear band of the TiC/TC4 composites led to the fracture. Further, the fracture surface analysis showed that the in situ nanoscale TiC reinforcement promoted the fracture of microbubbles from the α/β interface with the concentrated distribution of the V element to the interface between TiC and the Ti matrix because of the load transfer, which promoted the uniform distribution of the V element in the dimple.

Microstructure and mechanical properties of in situ TiC/Ti composites with a laminated structure synthesized by spark plasma sintering

A series of novel in situ TiC/Ti composites with laminated microstructure have been fabricated via electrophoretic deposition followed by spark plasma sintering (SPS), in which the electrophoretic deposition has been used to deposit graphene oxides (GOs) on commercially pure Ti foils and the SPS has been used to induce in situ reaction between Ti and GOs to form TiC and simultaneously achieve densification. With increasing deposition duration, the volume fraction of TiC reinforcement increases and the grain size of Ti matrix decreases in the as-sintered composites, resulting in continuous strength increment. Attributed to the introduction of TiC reinforcement and laminated structure, a strength increment of 93.9% can be reached with a considerable elongation of 6.1%. Moreover, different strengthening mechanisms are discussed and quantitatively evaluated based on microscopy analysis. • Laminated TiC/Ti composites were synthesized by spark plasma sintering. • The composites exhibited better strength-ductility combination. • The strengthening mechanisms are discussed and quantitatively evaluated.

Microstructural evolution, mechanical and tribological properties of TiC/Ti6Al4V composites with unique microstructure prepared by SLM

Based on the advantage of rapidly fabricating parts with complex geometric shapes, selective laser melting (SLM), an additive manufacturing technology, is utilized to process 3 wt.% TiC/Ti6Al4V composites. A TiC-reinforced Ti6Al4V composite with directionally grown unique microstructures is prepared by SLM. The effect of the laser power and scanning speed on the relative density, constitutional phases, and microstructure features is investigated systematically. The microstructure evolution mechanism is clarified. Moreover, the influence of the unique microstructure on the mechanical and tribological properties is investigated. The results indicate that the relative density of the SLM-processed TiC/Ti6Al4V composite can reach 98.7%. Because of the special processing technology used in SLM, unique nanoscale lamellar and needle-like eutectic TiC reinforcement phases, which have never been observed in TiC/Ti6Al4V composites prepared by other flexible laser additive manufacturing technologies, are formed. Furthermore, the composites are dominated by extremely small grains. The nanoscale eutectic TiC and refined grains significantly enhance the hardness and tensile strength of the composites. The microhardness and ultimate tensile strength reach 487 HV and 1565 MPa, respectively. More importantly, the nanoscale reinforcement promotes the migration of C and the formation of a dense solid lubricant film during friction, leading to excellent tribological properties at different applied loads. As the applied load increases from 5 N to 15 N, due to the enhancement of the effect of the nanoscale reinforcement, the tribological properties of the SLM-processed TiC/Ti6Al4V composites are further improved. At an applied load of 15 N, the friction coefficient and wear rate reach 0.303 and 1.221 mm 3 /m∙N, respectively. • TiC/Ti6Al4V composites with unique nanoscale eutectic TiC reinforcement are prepared by SLM for the first time. • The microstructure formation condition and corresponding evolution mechanism under different parameters are clarified. • The SLM-processed Ti6Al4V/TiC composite shows excellent mechanical and tribological properties. • Mechanical and tribological properties reinforcement mechanism of the SLM-processed Ti6Al4V/TiC composite is established.

Microstructural evolution, mechanical properties and wear behavior of in-situ TiC-reinforced Ti matrix composite coating by induction cladding

Abstract In this work, the in-situ fabrication of TiC/Ti composite coatings is realized by melting a mixture of Ti and graphite powders on Ti6Al4V substrate by a high-frequency induction heating coil under Ar atmosphere. The microstructural evolution, phase changes, micro/nano mechanical properties, and tribological behavior of the TiC/Ti composite coatings are systematically investigated. The in-situ growth mechanism of TiC and wear resistance mechanism of the TiC/Ti composite coatings are also discussed from the viewpoints of Ti C binary phase diagram, composition of raw powders, crystal structure of TiC and solidification conditions. The results indicate that the dissolution-precipitation mechanism dictates the in-situ growth of TiC reinforcements. Moreover, the morphology, dimensions and distribution of TiC phase in the TiC/Ti composite coating are strongly influenced by the composition of raw powders, crystal structure of TiC and induction cladding process. The high induction power and optimal coil scanning speed generate less heat input for the coating formation and fast solidification speed, resulting in fine TiC reinforcements, a narrow interface transition region and a heat-affected zone. Furthermore, the in-situ formation of reinforcements endows high hardness, good elasticity and excellent tribological properties to the TiC/Ti composite coatings.

Columnar to equiaxed grain transition of laser deposited Ti6Al4V using nano-sized B4C particles

A new laser melting deposition (LMD) method was employed for Ti6Al4V to stimulate the columnar to equiaxed transition (CET) via adding 1 wt% ~ 5 wt% nano-sized B4C particles. Results indicate that the grains were signifcantly refined from 600 μm to 11 μm with the increasing content of B4C; When the B4C content was 3 wt%, the B4C/Ti6Al4V composite achieved CET; TiB and TiC reinforcements were produced by in-situ reaction between the Ti6Al4V and B4C, which not only precipitated at the grain boundaries to restrict the grain growth, but also acted as nucleation sites to accelerate the non-spontaneous nucleation of β grains to achieve fine grain strengthening. Tensile tests show that adding 3 wt% B4C particles results in a signifcantly increased yield strength (1235 MPa) and tensile strength (1310 MPa) and maintains a certain amount of ductility (2.4% elongation). And the epitaxial growth of β grains in the underlying deposited layer and the CET mechanism with successive layer-upon-layer deposition were analyzed.

Manufacturing Fe–TiC Composite Powder via Inert Gas Atomization by Forming Reinforcement Phase In Situ

Fe–TiC metal matrix composite powder is manufactured applying vacuum inert gas atomization technique. The TiC reinforcement phase forms in situ within spraying of the Fe‐based molten metal preliminary alloyed with 1 wt% [C] and 4 wt% [Ti]. Alloying strategy, homogenization time, and spraying temperature are varied for three conducted atomization experiments in this study. Medium particle size (d50) lies in a range of 41–55 μm for obtained spherical powders. Scanning electron microscopy (SEM) analysis and Energy‐dispersive X‐ray spectroscopy (EDX) mapping of powder cross‐section samples reveal well‐dispersed submicron TiC precipitates of two different morphologies—primary‐blocky and eutectic‐plate‐shape carbides. The amount of precipitates and their morphology depend on the particle size. Namely, coarser powder particles tend to have more primary carbides that are presumably formed already in liquid droplets. Meanwhile, TiC precipitation in finer particles up to ≈25 μm is completely suppressed due to an extremely high cooling rate. Difficulties of the Fe–Ti–C melt atomization (e.g., formation of a semiliquid slag layer, loss of TiC forming elements, the presence of large precipitates in a powder) are discussed considering the thermodynamic analysis of this system and Fe–TiC remelting experiments conducted on a hot stage microscope.

In-situ development of Fe3C and TiC reinforcements during the mechanosynthesis of Cu–10Sn–15Ti/diamonds composite powders by high energy ball milling: Microstructural, thermal, and mechanical characterization

The development of iron and titanium carbides nanoparticles reinforcements during the mechanosynthesis Cu–10Sn–15Ti/diamonds composite powders from a mixture of blended Cu/Sn/Ti powders and synthetic diamonds (10 wt.%) was studied in this work. The analysis of the microstructure evolution showed that mechanical alloying performed at high-energy ball milling (600 rpm) allows developing different metastable phases depending on the SA content and milling time. For 3 wt.% of SA, XRD patterns revealed a metastable Cu(Sn) solid solution is produced after 5 h of MA while Fe2.939O4, FeTiO3 and TiH0.66 nanophases were formed for milling times higher than 15 h as a result of degradation of the SA in form of gaseous products (CO, CO2, H2, and lighter hydrocarbons (HC's)). XRD confirm that the release of these gases, along the SA degradation, and high carbon content carbon favors the carbothermic reduction of Fe2.939O4 for producing amorphous Fe3C nanoparticles at low-temperature thanks to the high-energy transferred in each impact during the MA process. For 1 wt.% of SA, XRD patterns showed the formation of Cu (Ti, Sn), from the very beginning of the process (5 h), is accompanied by the release of carboxyl groups (COOH) and crystallization of long heptadecane chains, CH3(CH2)15CH3. The high boiling point of this heptadecane chains and the low Fe released during milling, produces a lower content of amorphous Fe3C nanoparticles. DSC and SAED patterns performed in the mixture of both alloyed powders after heating up to 1000 °C showed the carbothermic reduction of FeTiO3 for producing TiC nanoparticles takes place preferably when a 3 wt.% of SA is used. In both cases, the resulting alloyed powders are composed by a mixture of crystalline Cu13.7Sn + Fe + Fe3C + C + TiC phases with an Fe, and Fe3C and TiC content lower in the case of the powders processed with 1 wt.% SA. The development of this dissimilar Fe3C and TiC content produces the mixture with 3 wt.% of SA shows a higher stiffness.

End mill studies on Al6061 hybrid composite prepared by ultrasonic-assisted stir casting

To produce the lightweight material for the high payload with excellent strength in particular for defense applications, reinforcements were introduced into the aluminum to form a hybrid composite. SiO2 was extracted through suitable techniques from rice husk ash particles. Through the ultrasonic probe sonication stir-casting process, the standard composition of 3% SiO2 was added along with varying weight percentages (3, 6, 9, and 12) of TiC particles as reinforcement in Al 6061 matrix. The machinability of the fabricated hybrid composite was evaluated through end face milling with varied machining parameters such as spindle speed, feed rate, and depth of cut. The output performance measurable characteristics were temperature and Ra. Thermal energy generated during the machining conditions was studied through the thermal image FLIR camera. From the machining conditions, machining level with SS of 1000, FR of 100, and DOC of 0.2 lead to having the highest temperature of 119 °C. The working temperature for the N2 sample was recorded to be 17% higher with an increase of 3% of TiC. The impact of wt% of reinforcements and governing parameters on tool wear was analyzed by SEM images. The addition of RHA and TiC reinforcements leads to raising cutting zone temperature, tool wear, and Ra. The thermal distortion effect on tool wear, chip morphology, and the surface profile of the samples were discussed and reported.

Selective laser melting of Hastelloy X nanocomposite: Effects of TiC reinforcement on crack elimination and strength improvement

The Hastelloy X (HX) nickel-based superalloy is increasingly applied in the aerospace industry because of its exceptional combination of oxidation resistance and high-temperature strength. The addition of nanoscale ceramic reinforcements to the HX alloy is expected to further improve its mechanical and thermophysical performance. The research challenge is to manufacture HX nanocomposites using additive manufacturing (AM) technologies, particularly selective laser melting (SLM), which has been used successfully to produce other nanocomposites. This paper systematically studies the microstructure and tensile performance of HX-3 wt.% TiC nanocomposite fabricated via SLM and explores the effects of TiC nanoparticles on hot-cracking elimination and strength enhancement. The findings reveal that the addition of 3 wt% TiC nanoparticles resulted in (1) an extra 73 J/mm3 laser-energy density needed to manufacture nearly full-density nanocomposite samples and (2) intergranular microcrack elimination due to the significant increase in grain boundaries induced by the grain refinement. The results showed a 17% increase in yield strength, while the elongation to failure was not significantly reduced. The results from the microstructure examination suggest that the strengthening mechanisms of load bearing and enhanced-dislocation density were the most pronounced mechanisms in the SLM-fabricated nanocomposite. These findings offer a promising pathway to strengthen mechanical performance by addressing the hot-cracking issue in the AM of nickel-based superalloys that suffer from cracking susceptibility. The results can also help to accelerate the uptake of AM in high-performance and defect-free superalloys for various applications.

Carbon Nanotubes Enabled Laser 3D Printing of High-Performance Titanium with Highly Concentrated Reinforcement.

SummaryZero- to two-dimensional nanomaterials have been incorporated into metal-matrices to improve the strength of metals, but challengingly, high-volume-fraction nanomaterials are difficult to disperse uniformly in metal matrices, severely degrading the ductility of conventionally processed metals. Here, a considerably dense uniform dispersion of in situ formed nanoscale lamellar TiC reinforcement (16.1 wt %) in Ti matrix is achieved through laser-tailored 3D printing and complete reaction of Ti powder with a small amount (1.0 wt %) of carbon nanotubes (CNTs). An enhanced tensile strength of 912 MPa and an outstanding fracture elongation of 16% are simultaneously achieved for laser-printed components, showing a maximum 350% improvement in “product of strength and elongation” compared with conventional Ti. In situ nanoscale TiC reinforcement favors the formation of ultrafine equiaxed Ti grains and metallurgically coherent interface with minimal lattice misfit between TiC lamellae and Ti matrix. Our approach hopefully provides a feasible way to broaden structural applications of CNTs in load-bearing Ti-based engineering components via laser-tailored reorganization with Ti.

Towards additively manufacturing excavating tools for future robotic space exploration

AbstractMultiple metal alloys, that is, Ti‐6Al‐4 V, 316 L stainless steel, MS1 maraging steel, A2 tool steel, Inconel 625 with TiC and TiB2 reinforcement, and AMZ4 bulk metallic glass, were additively manufactured through laser powder bed fusion and tested as potential excavating tools for future robotic spacecraft landing on icy planetary bodies. Mechanical specific energy as a function of blade hardness was measured for each excavating tool as it trenched through soft and hard salt, where the salt is a regolith simulant for extraterrestrial ice. A2 tool steel, MS1 maraging steel, and bulk metallic glass cutting tools were shown to perform well in the experiments. A method for using the cutting tool as a sensor was also demonstrated.

Achieving the excellent self-lubricity and low wear of TiAl intermetallics through the addition of copper coated graphite

The present work achieves excellent lubricity and low wear of TiAl intermetallics by the addition of low-cost copper-coated graphite. 50% reduction of friction and more than one magnitude lower wear rate were obtained. This superior tribological property is attributed to the formation of a soft tribo-film and a synergetic effect of in-situ formed harder TiC reinforcement. This tribo-film contains some graphite nanoplatelets, shell-like carbon, TiC particles and the mixture of some oxides. This work is helpful not only for the development of new solid self-lubricating composites but also promotes a scientific understanding of the tribo-film of solid lubricants.

Agglomeration-free nanoscale TiC reinforced titanium matrix composites achieved by in-situ laser additive manufacturing

A novel laser additive manufacturing method is proposed to manufacture the agglomeration-free nanoscale TiC-reinforced titanium-matrix composites by in-situ compounding the reinforcement via gas–liquid reaction. The clean interface and strong interfacial bonding between the in-situ nanoscale TiC reinforcement and the matrix alloy can significantly improve grain boundary behavior and grain boundary strength, besides, the mechanisms of achieving simultaneously high strength and high plasticity in the TiC/Ti6Al4V composites were studied. The proposed in-situ additive manufacturing method using pyrolysis-reaction would open a new route for manufacturing of the homogeneous and agglomeration-free nanocomposites parts with high-complexed structures and excellent mechanical properties.

Synthesis and mechanical characterization of Fe–BN–TiC nanocomposites

This Work summarizes the effect of BN and TiC reinforcement on Fe based nanocomposites prepared using powder metallurgy process. The microstructure, mechanical properties and wear resistance of the BN, TiC reinforced Fe based nanocomposites were investigated. The composite materials were characterized using Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM) and XRD. The results revealed that the addition of BN, TiC nanoparticles enhanced the microhardness and compressive strength of the composite materials compared to that of pure Fe, whereas the density of the composite materials has decreased considerably. The wear resistance of the Fe based nanocomposites showed betterment with addition of BN-TiC reinforcements compared to that of bare Fe.

Single step heat treatment for the development of beta titanium composites with in-situ TiB and TiC reinforcement

Titanium matrix composites have been attracting great interest from aerospace industry due to favorable properties like thermal stability, high specific strength, corrosion, and wear resistance. Optimal relation between mechanical properties demands complex processing routes and, in this context, the effects of a single-step processing route on microstructure and mechanical properties of β titanium matrix composites was placed on focus in this study. The commercial TIMETAL Beta 21S alloy and its modification with the addition of B4C were developed, allowing in-situ formation of TiB and TiC particles in a β matrix. The composites presented highest values of mechanical strength and hardness, and the addition of 3% of B4C provided a significant reduction in grain size, and compressive yield strength and ultimate compressive strength values of 1205 MPa and 1636 MPa, respectively, with a maximum deformation of 20.5%. An orientation relationship investigation provided information about some unconventional relation between the present phases.

Effect of network size on mechanical properties and wear resistance of titanium/nanodiamonds nanocomposites with network architecture

The Ti/nanodiamonds (NDs) composites with various network size were fabricated by spark plasma sintering (SPS) technique. The microstructure, mechanical properties and wear resistance of the nanocomposites were investigated. Experimental results showed that all the Ti/NDs nanocomposites exhibited pure α-Ti with in-situ formed nano-TiC and residual NDs phases. Hardness and compressive yield strength for the nanocomposites showed great enhancement compared to that of pure Ti while without much variation among different network size. Higher tensile yield strength and acceptable ductility were achieved for the composites; however, the ductility presented an increasing trend (from 8% to 33%) with decrease of the network size. The friction coefficient and wear weight loss of the nanocomposite were lower than that of the pure Ti and the wear resistance was improved with decreasing network size. The excellent integrated properties for the Ti/NDs nanocomposites with smaller network size (matrix particle size of 15–-53 μm) are resulted from a combination of quasi-continuous network microstructure, TiC and residual ND reinforcements strengthening and network interface strengthening. • Ductility of Ti/NDs nanocomposites was improved with decreasing network size. • Wear resistance of nanocomposites was enhanced with decreasing network size. • The nanocomposite with smaller network size possessed better integrated properties.

Microstructure and mechanical properties of lightweight TiC-steel composite prepared by liquid pressing infiltration process

A TiC reinforced steel composite was fabricated by a liquid pressing infiltration (LPI) process. The TiC reinforced steel composites with density <6.0 g/cm3 were fabricated with a high volume fraction of TiC reinforcement. The results showed that the core-rim structure in the composite was formed by partial dissolution of the reinforcement during the LPI process. The effect of dissolution of TiC particles on the microstructure and mechanical properties of the composites was investigated. Enhanced mechanical properties are attributed to the effective load transfer from the matrix to the TiC because of the strong interfacial bonding. This interfacial stability results from chemical bonding from the partial dissolution and the precipitation of the TiC during the process. In order to establish the correlation between the core-rim structure and properties of the composite, the hardness (H) and Young's modulus (E) were examined by nano-indentation.

Electrodeposited Ni–W–TiC Composite Coatings: Effect of TiC Reinforcement on Microstructural and Tribological Properties

Ni–W–TiC composite coatings were prepared via electrodeposition technique by dispersing the different amount of TiC particles into the plating bath. The Ni–W and Ni–W–TiC composite coatings containing different concentrations of TiC particles were characterized by using the scanning electron microscope, X-ray diffraction technique, Vickers microhardness test, surface roughness test, and tribology test. The results show that the Ni–W coatings containing reinforced TiC particles have shown a typical FCC Ni–W crystal structure with significantly higher Vickers microhardness. The amount of dispersed TiC particles into the plating bath considerably affected codeposition weight percent of TiC into the Ni–W matrix, as revealed by the EDS analysis. Ni–W–TiC samples demonstrated the decreased abrasive wear as compared to Ni–W coating and no characteristic features observed for the adhesive wear. Similarly, an improvement in coefficient of friction was observed in Ni–W–TiC composite coating as compared to Ni–W coating.

Study on tribological properties of Al-TiC composites by Taguchi method

The tribological behaviour of Aluminium metal matrix composite studied by adding TiC particles. Centrifugal casting method was used for the preparation of composite specimens. The samples were prepared with varying the weight percentage of TiC particles such as 2.5%, 5% and 7.5%. The Taguchi technique was used for preparation of design of experiments by considering weight percentage, load and sliding distance as control parameters. The specific wear rate and coefficient of friction is determined with the help of Ducom made pin on disc machine. The ANOVA is applied to predict the effect of each factor over specific wear rate and coefficient of friction. The results show that the weight percentage of TiC reinforcement has significant effect on specific wear rate as well as coefficient of friction. The wear resistance of composite material is increased with increase in TiC reinforcement. The mathematical model through regression is predicted for specific wear rate and coefficient of friction.

Two-Body Abrasive Wear Behaviour of In-Situ Al-TiC Particle Composites: Influence of TiC Reinforcement and Content in the Alloy Matrix and Experimental Parameters

This study pertains to observations made on the abrasive wear response of Al-TiC composites under varying applied load and traversal distance conditions. The influence of TiC particle reinforcement and its content in the matrix on the abrasion characteristics of the samples was investigated. The composites were prepared by generating the reinforcement phase (TiC particles) from within the matrix employing a hybrid in-situ technique consisting of a combination of steps involved in powder and liquid metallurgy routes of synthesizing metal matrix composites. The unreinforced matrix alloy (AA2014) was also tested under identical experimental conditions for comparison purposes. Properties characterized were wear rate, frictional heating and friction coefficient. Microstructural features of the samples and characteristics of wear surfaces, subsurface regions and abrasive medium have also been examined.&#x0D; &#x0D; The TiC reinforcement led to improved abrasion resistance (inverse of wear rate), the degree of improvement increasing further with the rising concentration of the TiC particles in the alloy matrix. Increasing applied load led to deterioration in the wear behaviour of the samples while a reverse trend was followed as the traversal distance was raised. The severity of frictional heating was noted to increase with load. On the contrary, friction coefficient tended to decrease with increasing load except for the composite containing the highest concentration of TiC wherein a reverse trend was noticed. Both frictional heating and friction coefficient increased sharply with traversal distance initially. This was followed by a reduction in the rate of temperature increase at longer traversal distances whereas friction coefficient was observed to attain steady state condition after showing a decrease in some cases. The presence of TiC reinforcement in the alloy matrix and its increasing content led to a decrease in the friction coefficient and the severity of frictional heating. The observed wear behaviour has been substantiated through the characteristics of abraded surfaces and subsurface regions of the samples and degradation of the abrasive medium. Operating material removal mechanisms have also been examined.