Content Of TiC Particles Research Articles

Improvement in microstructure and mechanical properties of wire arc additively manufactured 7075 aluminum alloy via adjusting TiC particle addition

7075 aluminum alloys with varying TiC particle additions were fabricated by simultaneously depositing a standard 7075 wire and a TiC treated wire at different wire feed speed ratios. The effects of TiC content on the microstructure and mechanical properties of 7075 alloy were investigated. Results indicated that the addition of TiC particles can effectively refine the grain structure through heterogeneous nucleation, and the grain refinement effect was enhanced with increasing TiC particle content in the range of 0–0.70 wt%. Moreover, TiC particles can restrain the continuous distribution of second phase at grain boundaries. TiC particles tended to cluster at grain boundaries as its content exceeded 0.48 wt%, which adversely affected their beneficial effect on the improvement of mechanical properties. At an optimal TiC content of 0.48 wt%, the tensile strength and elongation in the horizontal direction exhibited remarkable enhancements of 27.2% and 319%, respectively, compared to those without the addition TIC particle.

Interfacial bonding and wear behavior of macroscopic TiC particulates reinforced iron-based composites fabricated by infiltration casting process

In this study, the interfacial bonding, mechanical properties and wear behavior of TiC particulates reinforced iron-based composites fabricated by infiltration casting process were investigated. TiC serves as a carbon source to formed (Fe,Cr)7C3 nearby, which facilitates the formation of metallurgical bonding between TiC and iron matrix. The maximum hardness values of TiCP zone for different specimens are over 3 times higher than iron matrix. The morphological changes of composites in real-time during three-body wear process were presented “shadow effect” and “peak-valley phenomenon”. The volumetric relative wear resistance of TiCP/Fe composites with different content of TiC particles increased by 18.2–66.7 % compared with matrix. This work contributes to the potential of millimeter-level TiC as a reinforcement particle of composites in industrial application.

Microstructure and wear resistance of in-situ TiC reinforced Stellite 6 coating using PTA cladding

To enhance the durability of copper tuyeres in blast furnaces, it is necessary to apply coatings on their surfaces to protect against wear caused by high-temperature coke. In this study, a series of in-situ synthetic TiC-reinforced Stellite 6 alloy coatings containing a Ni60A interlayer were successfully produced on copper substrates using 5–45 wt% TiFe/Cr3C2 precursor powders. The coatings exhibited excellent metallurgical bonding with the Ni60A interlayer, and an elemental transition zone was formed at the interface between the coating and the interlayer. XRD Rietveld refinement analysis revealed that the T45 coating with 45 wt% of precursor powder showed the highest TiC phase content of 12.27 %, with an average hardness of 658.15 HV0.2, which was 31.2 % higher than that of the Stellite 6 alloy. The wear mechanism of the Stellite 6 coating was plastic delamination at 25 °C, and oxidative wear at 500 °C. As the TiC particle content in the coating increased, the dominant wear mechanism tended to shift towards abrasive wear. The specific wear mechanism of the coating was influenced by the content of coating phases and the operating temperature. The best wear resistance was achieved by the T45 coating, which showed an abrasive wear mechanism at both 25 °C and 500 °C, with a wear resistance of 4.47 and 5.94 times higher than that of the Stellite 6 alloy respectively.

Fabrication of high-performance CoCrNi medium entropy alloy by laser powder bed fusion: The effect of grain boundary segregation

A CoCrNi composite material with 3 wt% TiC was successfully fabricated by laser powder bed fusion (LPBF). With increasing content of TiC particles, C gradually segregated along the grain boundaries (GBs). The segregation of C improved the grain coalescence, intensified the attraction of the columnar grains, and increased the consumption of the liquid film. Furthermore, the segregation of C led to the formation of Cr23C6 and core–shell structure (TiO2/TiC) nanoprecipitates along the GBs. These precipitates reduced the mobility of the boundaries and restricted the grain growth along the direction of the maximum thermal gradient. Reinforcing the CoCrNi microstructure with 3 wt% TiC yielded optimal results, as the resultant composite microstructure was free of hot cracks, consisted of small grains, and exhibited a more random texture. The high density of wide stacking faults and Lomer–Cottrell locks hindered cross-slip during further deformation at ambient temperature, and twins dominated at elevated temperatures. These nanoprecipitates hindered dislocation propagation at all temperatures. Therefore, the synergistic strengthening effects from the different types of dislocations and nanoprecipitates endowed the CCN-3M alloy with excellent mechanical properties. Ultimate tensile strengths of approximately 1.34 and 0.88 GPa, yield strengths of approximately 1.02 and 0.75 GPa, and elongations of approximately 15.6% and 25.3% were observed at ambient and elevated temperatures (700 °C), respectively. These results indicate that GB segregation is an effective method for suppressing the evolution of hot cracks, thus expanding the scope of LPBF-fabricated components for industrial applications.

Improvement of mechanical properties and corrosion resistance for wire arc additive manufactured nickel alloy 690 by adding TiC particles

Nickel alloy 690 (Ni690) were fabricated by wire arc additive manufacturing (WAAM) with three kinds of TiC particles adding contents (no TiC addition, 0.5 wt% TiC, 1.0 wt% TiC) based on cold metal transfer (CMT) technology. The effects of TiC particles adding content on the microstructure, mechanical properties and corrosion resistance were investigated. After adding 1.0 wt% TiC particles, the average length of the γ grains decreased from 301 ± 61 µm to 114 ± 15 µm and the structure of grains changed from columnar dendrite into equiaxed dendritic at the top of each layer, which is results of the heterogeneous nucleation and increase of constitutional supercooling caused by TiC particles. The difference between horizontal and vertical mechanical properties of WAAM Ni690 component disappeared because the heterogeneous nucleation caused by TiC particles prevented the epitaxial growth. The ultimate tensile strength of the WAAM 1.0TiC-Ni690 component reached 590 MPa in both directions, which increased 10 % compared with no TiC addition. The improvement of mechanical properties was owing to the grain refinement and the formation of reinforcing TiC/(Ti, Nb)C second-phase particles. The potentiodynamic polarization tests showed that the improved corrosion resistance with the increased content of TiC particles. The electrochemical impedance spectroscopy (EIS) tests results showed that due to the refined γ columnar grains providing more nucleation sites, a denser and thicker passive film was formed, which improved the corrosion resistance. The composition of the passive film was analyzed by X-ray photoelectron spectroscopy (XPS). The results reflected the more content of oxides and hydroxides of Cr in the passive film of WAAM 1.0TiC-Ni690 sample represented the denser passive film and better corrosion resistance.

The Wear Behavior of the Laser Cladded Ti-Al-Si Composite Coatings on Ti-6Al-4V Alloy with Additional TiC.

In this study, the Ti-Al-Si + xTiC (x = 0, 2, 6, 10 wt.%) composite coatings, each with a different content of TiC were fabricated on a Ti-6Al-4V alloy by laser surface cladding. The microstructure of the prepared coatings was analyzed by the scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The microhardness and the wear resistance of these coatings were also evaluated. The results show that α-Ti, Ti3Al, Ti5Si3, TiAl3, TiAl, Ti3AlC2 and TiC particles can be found in the composites. The microstructure can obviously be refined by increasing the content of TiC particles, while the microhardness increases and the coefficient of friction decreases. The Ti-Al-Si-6TiC composite shows the best wear resistance, owing to its relatively fine microstructure and high content of TiC particles. The microhardness of this coating is 5.3 times that of the substrate, while the wear rate is only 0.43 times. However, when the content of TiC was up to 10 wt.%, the original TiC could not be dissolved completely during the laser cladding process, leading to formation of cracks on the coatings.

Effects of TiC nanoparticle additions on microstructure and mechanical properties of FeCrAl alloys prepared by directed energy deposition

• Near fully dense TiC particles strengthened FeCrAl alloys have been fabricated by directed energy deposition. • TiC additions significantly refine the grain sizes and prompt columnar to equiaxed grain transition. • TiC particles strengthened FeCrAl alloys have good mechanical properties both at room temperature and high temperature of 650 ℃. Directed energy deposition (DED) additive manufacturing process has been attractive to the fabrications of FeCrAl alloys due to the advantage of near net shaping of complex shaped components. In order to improve the strength, TiC particles strengthened FeCrAl alloys have been fabricated by DED using blended FeCrAl powder and TiC nanoparticles. The results show that the TiC particles in the DED alloys have submicron sizes, and polygonal or dendritic shapes. Most TiC particles are distributed along the dendritic/grain boundaries. The additions of TiC particles effectively refine the grain sizes, and at the same time prompt a columnar to equiaxed transition of grains. The grain sizes are reduced from 1377 μm to 47 μm, 21 μm and 22 μm when the TiC particle contents in the DED alloys increase from 0 wt% to 0.7 wt%, 2.4 wt% and 3.5 wt%, respectively. The room temperature strength of the FeCrAl alloys increase with the increase of TiC particle content. With 3.5 wt% TiC particle content, the FeCrAl alloy has good mechanical properties with yield strength of 437 MPa, ultimate tensile strength of 688 MPa, and an elongation of 19 %. The 650 ℃ high temperature strength of the FeCrAl alloys first decrease and then increase with the increase of TiC particle content. With 3.5 wt% TiC particle content, the FeCrAl alloy has excellent mechanical properties with yield strength of 208 MPa, ultimate tensile strength of 223 MPa, and an elongation of 53 %. The present study provides an important basis for fabricating high strength particle-strengthened FeCrAl alloys using the DED process.

Friction behavior of Ti-30Fe composites strengthened by TiC particles

Abstract Ti−Fe−xTiC (x=0, 3, 6, 9, wt.%) composites were fabricated through low temperature ball milling of Ti, Fe and TiC powders, followed by spark plasma sintering. The results show that β-Ti, β-Ti−Fe, η-Ti4Fe2O0.4 and TiC particles can be found in the composites. The microstructure can be obviously refined with increasing the content of TiC particles. The coefficient of friction (COF) decreases and the hardness increases with increasing the content of TiC particles. The adhesive wear is the dominant wear mechanism of all the Ti−Fe−xTiC composites. The Ti−Fe−6TiC composite shows the best wear resistance, owing to the small size and high content of TiC particle as well as relatively fine microstructure. The wear rate of the Ti−Fe−6TiC composite is as low as 1.869×10−5 mm3/(N·m) and the COF is only 0.64. Therefore, TiC particle reinforced Ti−Fe based composites may be utilized as potential wear resistant materials.

The effect of high TiC particle content on the tensile cracking and corrosion behavior of Al–5Cu matrix composites

The high-TiC particle volume fraction on the mechanical properties and corrosion behavior of the A–5Cu matrix composites were investigated with porosity, hardness, tensile tests, and polarization measurements. The composites reinforced with 18, 27, and 50 vol% TiC particulates were produced successfully by using hot-pressing technique under Ar atmosphere and characterized by scanning electron microscope, electron dispersive spectroscope, and X-ray diffraction. The corrosion susceptibilities of the composites were compared with potentiodynamic scanning technique. It was found that the hardness of the composites increases while the fracture strength decreases with increasing TiC reinforcement content in the matrix. The corrosion susceptibilities of 18 and 27 vol% TiC-reinforced composites are almost the same; the corrosion rate of 50 vol% TiC-reinforced composite was approximately 10 times higher than the composites reinforced with 18 and 27 vol% TiC particles in the 3.5% NaCl. In addition, some preferential corrosion attacks were detected at TiC/matrix interfaces and in TiC clusters during the corrosion process of the composites. Therefore, the porosity content in the composites was almost the same level.

Microstructure, Corrosion and Mechanical Properties of TiC Particles/Al-5Mg Composite Fillers for Tungsten Arc Welding of 5083 Aluminum Alloy.

A semi-solid stir casting mixed multi-pass rolling process was successfully employed to manufacture TiCp/Al-5Mg composite filler wires with different contents of TiC particles. The 5083-H116 aluminum alloys were joined by tungsten inert gas (TIG) using TiCp/Al-5Mg composite weld wires. The microstructure, mechanical properties, fractography and corrosion behavior of the welds were evaluated. The results revealed that TiC particles were distributed in the welds uniformly and effectively refined the primary α-Al grains. The hardness and tensile strength of the welds were improved by increasing the TiC particle content, which could be attributed to the homogeneous distribution of TiC particles and the microstructure in the weld joints. Potentiodynamic polarization testing revealed that the corrosion resistance of the welds also increased with the addition of TiC particle contents. In addition, the stress corrosion cracking (SCC) susceptibility of the welds decreased as micro-TiC particles were introduced into the welds. The electronic structure of the Al/TiC interface was investigated by first principle calculation. The calculation showed that valence electrons tended to be localized in the region of the TiC-Al interface, corresponding to an addition of the overall work function, which hinders the participation of electrons in the composite in corrosion reactions.

Superior tensile fracture strength of hot isostatically pressed TiC–steel metallic composite fabricated by a novel infiltration

A metallic composite having TiC particle content as high as ~47 vol% in a cold work tool steel matrix was successfully fabricated by a novel infiltration process. The penetration of the liquid steel reached geometrically complex regions, such that no interfacial flaw was observed. The interface between the ferrite matrix and TiC was semicoherent with a faceted morphology consisting of low-index planes of each phase. Owing to these characteristics of the interface, neither interfacial decohesion nor cracking was observed after the tensile fracture. The initial failure occurred in the TiC particle by a {100} cleavage fracture. The cracks formed from each fractured TiC particle interlinked forming a major crack. The hot-isostatically pressed composite exhibited 16% higher strength (919 MPa) than the as-infiltrated composite (791 MPa). The fracture strength of the composite largely depended on the degrees of suppression of the TiC cracking and its propagation. The residual stresses pertaining to the TiC and steel matrix were measured by X-ray diffraction. They were not significant factors responsible for the increased fracture strength of the hot-isostatically pressed composite. The increased strength of the hot-isostatically pressed composite could be explained in terms of the mutually interactive influences of the load transfer mechanism, matrix toughening, reduced TiC contiguity, and M7C3 carbide bridging TiC particles.

Laser rapid forming processing of TiC reinforced nickel-based superalloy composites: Influence of additive TiC particle content

The present investigation concerned the fabrication of TiC (2.5 and 5 wt. %) reinforced nickel-based superalloy (NBS) composites by laser rapid forming (LRF) with a high power diode laser. Furthermore, the evaluation of microstructures and the wear resistance of the laser manufacturing specimens were researched. There were four different species of microstructures in LRF-processed pure NBS parts and 2.5% TiC/NBS composites, including cellular grains, columnar grains, crosslike grains, and columnar dendrites. However, only cellular grains could be observed in the 5% TiC/NBS composite parts. Moreover, when micro-TiC particles were added as reinforcements, relatively coarsening microstructures were obtained by the LRF processing compared with the unreinforced NBS parts. Generally, the LRF-processed 5% TiC/NBS composites showed the best efficiency in improving the tribological property compared with the pure NBS and 2.5% TiC/NBS composite parts. It indicated that the dominant wear mechanism was adhesive wear when unreinforced NBS sliding against GCr15 counterpart ball, while 2.5% TiC/NBS composite underwent adhesive wear and abrasive wear simultaneously. However, the predominant wear mechanism of 5% TiC/NBS composite changed into abrasive wear. The energy dispersive x-ray spectroscopy analyses could be the evidence that oxidative wear also occurred between the sliding pair of TiC/NBS composites and GCr15 during the dry sliding wear test.

Effects of Nano TiC Particles on Recrystallization and Mechanical Properties of Al-Zn-Mg-Cu Alloy

The recrystallization and mechanical properties of 7085 alloy and TiC/7085 composites with different nano TiC content (0.1, 0.3, 0.5, and 1 wt%) were investigated in this work. Results showed that as the TiC content increased from 0.1 to 1 wt%, dynamic recrystallization was promoted in which the composites proceeded by hot deformation; after T6 treatment, static recrystallization was hindered. In addition, the ultimate strength of composites first increased and then decreased with the increase of nano TiC particle content from 0.1 wt% to 1 wt%. When the content of nano TiC particles reached 0.5 wt%, the tensile strength of the nanocomposites was improved to 608 MPa, 12% higher than that of 7085 alloy, via the reinforcing particle strengthening mechanism. Due to the grain coarsening and the TiC particle cluster, the ultimate tensile strength of 1 wt% TiC/7085 composite decreased to 585 MPa.

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

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

Dry sliding wear behavior of Fe3Al and Fe3Al/TiC coatings prepared by HVOF

This investigation aims to reveal the effect of TiC particles on the wear resistance of Fe3Al/TiC composite coatings against alumina counterbody. The coating feedstock, in powder form, was produced by high-energy ball milling of Fe3Al, Ti and graphite powders. The coatings were provided by spraying the feedstock on a steel substrate using the High-Velocity Oxy-Fuel (HVOF) technique. The effect of TiC addition on dry sliding wear rates of the coatings at sliding speeds ranging from 0.04 to 0.8m.s−1 and under a constant load of 5N was studied. Coatings made from pure Fe3Al exhibited a relatively high wear rate. The Vickers hardness and wear resistance of the coatings increased with increasing TiC content in the Fe3Al matrix. The wear mechanism strongly depends on the sliding speed and the content of TiC particles. It was observed that at low sliding speed, the predominant wear mechanism of the coatings with 0, 10 and 30mol.% TiC was fatigue wear, whereas at high sliding speeds, the wear mechanism is oxidation. For Fe3Al–50mol.% TiC and Fe3Al–70mol.% TiC composites, abrasive and oxidation wear are most likely the dominant wear mechanisms.

Microstructures and properties of in-situ TiC particles reinforced Ni-based composite coatings prepared by plasma spray welding

In this investigation, the in-situ TiC particles reinforced Ni-based composite coatings were produced by plasma spray welding with mixed powders (NiCrBSi+Ti+NiCr–Cr3C2). Their microstructures and properties were studied. The experimental results showed that the composite coatings consisted mainly of γ-Ni, Cr23C6, Cr7C3, Ni3Si, Cr5B3, CrB, FeNi3 and TiC phases. TiC particles were in-situ synthesized during plasma spray welding. The content of TiC particles and chromium carbides in the coatings increased with the mass fractions of Ti and NiCr–Cr3C2 powders increasing in the mixed powders, which resulted in enhancing the composite coatings hardness. The composite coating prepared with the mixed powder (70wt%NiCrBSi+30wt% (Ti+NiCr–Cr3C2)) showed a higher hardness 1142HV0.5. The wear resistance of the composite coatings were greatly improved due to the presence of in-situ TiC particles in comparison with the substrate. When the mixed powder (75wt%NiCrBSi+25wt% (Ti+NiCr–Cr3C2)) was used, the composite coating had better wear resistance, and the coating wear volume loss after wear tests was 6mm3, which was only 5% of that for the low carbon steel substrate (125mm3).

High-efficiency control of phase separation in Al-based immiscible alloys by TiC particles

In this work, the sedimentation of In/Bi phase in Al–In/Bi immiscible alloy was overcome by the high-efficiency control of its aggregation. Results showed that the addition of TiC particles resulted in a uniformly dispersive micron-sized phase of immiscible alloy. The mechanism for inhibiting phase separation was attributed to be that the suspending TiC particles prevented In/Bi phase from aggregation and sedimentation within liquid miscibility gap. The size and morphology of Bi phase can be modulated by changing the content of TiC particles, from perfect sphere to defective sphere, and then up to irregular micron-sized phase. Our approach fundamentally alters the aggregation mode of droplet, which may provide a general route for fabricating homogeneous immiscible alloy.

Tribological properties of TiC particles reinforced Ni-based alloy composite coatings

The TiC particles reinforced Ni-based alloy composite coatings were prepared by plasma spray. The microstructure and tribological properties of the composite coatings were investigated. The results show that the composite coatings are mainly composed of γ-Ni, CrB, Cr7C3 and TiC. A transition layer of 9.4 μm in thickness forms at the interface, indicating the metallurgy bond between the composite coating and the substrate. When the content of TiC particles is 30% in volume fraction, both of the friction coefficient and wear rate of the composite coatings reach the lowest values. The friction coefficient is 0.33 which is reduced by 30% compared with the pure Ni-based alloy coating; the wear rate is 0.3×10−3 mm3/m which is about 1/3 that of latter. Under the load of 6-10 N, the composite coatings are in a slight wear stage and their wear mechanisms are mainly adhesive wear. Under the high load of 12 N, the composite coatings suffer from severe wear, and the wear mechanisms change into the desquamation of the hard phases and the delamination of the transferred layer.

Microstructure and Mechanical Properties of TiC<sub>p</sub>/ZA-12 Composites

TiCp/ZA-12 composites have been fabricated by XDTM method and stirring-casting techniques. The behavior of TiC particle in the solidification interface has been studied through conventional and directional solidification techniques. The results demonstrate that under conventional solidification conditions, the particles with lower content mainly distribute in eutectic phases; while when at a larger content of TiC particles, they exist both in eutectic phases and in primary phases. Under directional solidification, due to the repulsion of primary phases of alloy on TiC particles, the particles congregate and form band structure, and extent of the congregation in band structure relates to TiC particles content. With the increasing of TiC particles content, their congregation in band structure decreases, and the band structure disappears when the content of TiC particles exceeds 6%. The tests for mechanical properties reveal that the tensile strength and yield strength increase with increasing fraction of TiC particles. When the fraction of TiC particles increase up to 10%, the tensile strength and yield strength are 390MPa and 340MPa, respectively and they increase by 11% and 17% than that of matrix respectively.

Stainless steel binder for the development of novel TiC-reinforced steel cermets

Steel reinforced TiC composites are an attractive choice for wear resistance and corrosion resistance applications. TiC-reinforced 17-4PH maraging stainless matrix composites were processed by conventional powder metallurgy (P/M). TiC-reinforced maraging stainless steel composites with >97% of theoretical density were fabricated. The microstructure, mechanical and wear properties of the composites were evaluated. The microstructure of these composites consisted of spherical and semi-spherical TiC particles. A few microcracks appeared in the composites, showing the presence of tensile stress in the composites produced during sintering. Typical properties, namely, hardness and bend strength were reported for the sintered composites. After heat treatment and aging, the increase of hardness was observed. The increase of hardness was attributed to the aging reaction in the 17-4PH stainless steel. The precipitates appeared in the microstructure and were responsible for the increase in hardness. The specific wear behavior of the composites was strongly dependent on the content of TiC particles, the interparticle spacing, and the presence of hard precipitates in the binder phase.