TiC Phase Research Articles

Microstructure and Mechanical Properties of In Situ Synthesized Metastable β Titanium Alloy Composite from Low-Cost Elemental Powders

The titanium matrix composite was produced through a hot compaction process at 1250 °C using the mixture of elemental powders with chemical composition of Ti-5Al-5Mo-5V-3Cr and 2 wt.% addition of boron carbide. The phase analysis via X-ray diffraction method was performed to confirm the occurrence of an in situ reaction between boron carbide and titanium. Then, the wide-ranging microstructural analysis was performed using optical microscopy as well as scanning electron microscopy along with energy-dispersive X-ray spectroscopy and electron backscatter diffraction. Based on this investigation, it was possible to describe the diffusion behavior during hot compaction and possible precipitation capabilities of TiC and TiB phases. Tensile and compression tests were conducted to determine the strength properties. The investigated composite has an ultimate tensile strength of about 910 ± 13 MPa with elongation of 10.9 ± 1.9% and compressive strength of 1744 ± 20 MPa with deformation of 10.5 ± 0.2%. Observation of the fracture surface allowed us to determine the dominant failure mechanism, which was crack propagation from the reaction layer surrounding remaining boron carbide particle, through the titanium alloy matrix. The study summarizes the process of producing an in situ titanium matrix composite from elemental powders and B4C additives and emphasizes the importance of element diffusion and reaction layer formation, which contributes to the strength properties of the material.

Predicting crystallite size of Mg-Ti-SiC nanocomposites using an adaptive neuro-fuzzy inference system model modified by termite life cycle optimizer

In this study, Mg-Ti-SiC composite powders with varied micron and nano silicon carbide (SiC) particle sizes were fabricated utilizing the ball milling technology at various milling times. The effect of reinforcement particles sizes and milling time on the morphology and microstructure of the magnesium composite powders was characterized. Then, we developed a machine-learning model based on Adaptive Neuro-fuzzy Inference System (ANFIS) modified with termite life cycle optimizer to predict the crystallite size of the produced composites. The average particles size in all composites including micron SiC (µSiC) and nano SiC (nSiC) always decreased with increasing milling time and SiC content, and the most optimal reduction in particle size was achieved after 16 h of milling for both configurations, which were 5.12 µm and 1.96 µm, respectively. Changing reinforcement particle size from micron to nano caused the peak intensities of Mg and Ti more decreased and phases Ti5Si3 and TiC were observed after milling for 16 h in ND composite powder. With increasing milling time in Mg-25 wt% Ti-5 wt% µSiC, the crystallite size decreased from 31 nm to 13.62 nm after 1 h and 32 h milled, respectively. The most optimum reduction in crystallite size occurred in the composite powders including nSiC, in which crystallite size decreased to 13.35 nm. The developed Machine learning model was able to predict the evolution of the crystallite size of the produce d composites with very good accuracy.

Microstructure and mechanical properties of in-situ B4C reinforced TC4 composites prepared by laser melting deposition

In order to satisfy the increasingly harsh service environments of modern aircrafts, the novel in-situ reinforced xB4C/TC4 (x = 0–1.5 wt%) composites were prepared by laser melting deposition (LMD) and their microstructure, mechanical properties were investigated. The dual reinforcement phases of TiC and TiB were formed after B4C addition. A more favorable microstructure of refined α-Ti grains and uniformly-distributed reinforcement phases was obtained after adding 0.5 wt% B4C. The 0.5B4C/TC4 composite exhibited a moderate anti-abrasion ability owing to its beneficial microstructure and relatively high microhardness. Furthermore, it possessed the highest strength due to the effects of grain strengthening and dispersion strengthening induced by the (TiC + TiB) phases. This work provides theoretical basis and technical guidance for the development of high-performance Ti matrix composites.

Complex TiC-Ni-based composites joined to steel support by thermal explosion under load: synthesis, microstructure and tribological behavior

ABSTRACT The combustion in thermal explosion mode of reactive mixtures of Ti–Ni–graphite(carbides, borides, oxides), under load, was used to produce complex composite materials, densified and joined to a C55 carbon steel support. The ignition of the exothermic reaction, carried out thanks to the rapid high-frequency heating of a green compact up to 1573 K, was followed by an isothermal holding at 1373 K for 360 s. This procedure ensured a perfect mechanical assembly between the composite material and the steel substrate. SEM analysis and concentration profiles carried out at the interface testified to the interdiffusion of iron and titanium atoms between the two materials. The maximum combustion temperature (Tmax.) exceeding 2200 K induced the appearance of a liquid phase that assisted densification and joining, and in which a part of the additions was dissolved before cooling. The starting chemical composition of reactive mixtures largely determined the microstructure, hardness and tribological behavior of the composites after the process. Thereby, the maximum hardness (1235 HV0.15) and the lowest wear rate (1.824 × 10−6 mm3.N−1.m−1) were obtained in the sample containing TiC, Al2O3 and TiB2 hard phases. The manufactured samples exhibit no deterioration of the composite by spalling, regardless of the starting composition.

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.

Carbon and Titanium Effect on Tensile Behavior of Aged A286 Nickel-Iron Based Superalloy

A286 nickel-iron based superalloy used in high temperature applications. Age hardening is done to enhance the creep behavior which is much affected by TiC and eta (ⴄ (Ni3Ti)) phases. Effect of carbon and titanium (0.02C-2.46Ti, 0.04C-2.54Ti, 0.05C-2.58Ti, and 0.06C-2.62Ti) on tensile behavior of aged A286 superalloy is systematically investigated via TiC and ⴄ (Ni3Ti) phases. It has been revealed that carbon and titanium contents are in proportional to nucleation of TiC and eta phases in the austenitic matrix of this alloy. Precipitation of these phases enhanced yield strength from 354MPa to 501MPa and ultimate tensile strength (UTS) 543MPa to 651MPa. However, plasticity decreased nearly 4%. Fracture topography showed that the ductile transgranular fracture in low C-Ti alloys are due to TiC particles, whereas in high C-Ti alloys fracture nature is found brittle intergranular due to eta phases.

Surface Hardening of CP Ti by Laser Hardening and Development of Ti/TiC Surface Composite by Laser Sintering Technique for Wear Resistant Surface

This study deals with the hardening of titanium surface by carburising of CP Ti Gr 2 substrate by using laser sintering process. The objective of this project is to harden the surface to improve surface wear resistance of titanium. In this study graphite powder is used as source of Carbon. Carbon from graphite reacts with titanium and TiC layer of 109 micron was measured on the titanium surface. The microstructure and phase analysis results show that presence of only TiC phase on the surface of the titanium substrate. TiC grains are nearly 5 times finer than titanium substrate grains. Grain refinement of TiC phase all over the surface of the substrate resulted in increase in hardness and development of significant wear resistance surface in titanium substrate. Hardness of TiC layer was found to be 2191Hv which is nearly ten times higher than the substrate titanium. Wear test results of pin and disc type shows negligible wear rate as compared to CP Ti substrate. TiC grains are nearly 5 times finer than titanium substrate grains.

Effect of the C/N ratio modification on the corrosion behavior and performance of carbonitride coatings prepared by cathodic arc deposition

This study focuses on investigating carbonitride coatings, specifically CNTi-(Zr, ZrNb, and ZrSi), as promising candidates for enhancing the durability and efficiency of Ti6Al4V materials used in nuclear fusion technology. X-ray diffraction analysis identified distinct phases, including TiN, ZrN, ZrC, and TiC. The corrosion studies showed complete degradation of the TiN, ZrC, and ZrN phases in the TiZrCN coating after tests, while the TiC phase exhibited relative stability. The surface morphologies and elemental mapping analysis demonstrated the loss of homogeneity in element distribution after corrosion process. The addition of Si and Nb elements into TiZrCN significantly influenced the coatings' corrosion behavior, with breakaway corrosion observed in CNTi- (Zr and ZrSi) coatings and localized corrosion in CNTi-(ZrNb) coatings. Notably, the CNTi-(ZrSi) coating formed an oxide phase in the presence of NaCl, whereas the CNTi-(ZrNb) coating exhibited continuous resistance and a low corrosion rate. Irradiation was carried out for the generation of active isotopes, showing that no radioactive isotopes were formed in any of the investigated samples.

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.

Effect of GO content on microstructure and mechanical properties of Ti6Al4V coating reinforced artificial joint.

In this study, we have innovatively proposed a method of in-situ synthesized TiC hard phase to improve the surface mechanical properties of artificial joint materials (Ti6Al4V). In order to explore the optimum graphene oxide (GO) addition, GO/Ti6Al4V composite powders with different proportions (0, 0.5, 1.0, and 1.5 wt.%) were prepared. The homogeneously dispersed GO/Ti6Al4V composite powder was prepared on Ti6Al4V substrate by laser cladding technology. The microstructure, phase composition, and mechanical behavior of GO/Ti6Al4V composite coatings were studied by scanning electron microscope (SEM), optical microscope (OM), energy dispersive spectrometer (EDS), tribometer, hardness tester, and surface profiler. The results showed that the addition of GO could significantly improve the mechanical properties of TC4 substrate. During the preparation of the coating, the grain size of in-situ TiC phase was nanoscale and was distributed between acicular martensite, which played a critical role in enhancing the mechanical properties of the coating. The TiC phase distributed between acicular martensite refine the grain size of phase and improve the cutting resistance of the coating. Nevertheless, excessive GO decreased the fluidity of the molten pool, and micro holes tended to generate in the coating, which had a negative impact on the mechanical properties of the coating. At the GO content of 0.5 wt.%, the microhardness of the GO/Ti6Al4V coating was 1.325 times that of pure Ti6Al4V. Under the friction environment of simulated body fluid solution, the average friction coefficient was approximately 0.307 and the wear rate decreased to 3.5 × 10-7 mm3/N · m.

TiC morphology and corrosion resistance of CrMnFeCoNi+x(TiC) coatings prepared by laser cladding

The corrosion resistance of CrMnFeCoNi coatings with varying TiC contents and the evolution of TiC within these coatings were comprehensively investigated. These CrMnFeCoNi coatings, with different TiC concentrations, were fabricated using laser cladding technology. The behavior of TiC evolution in CrMnFeCoNi coatings was observed to follow a distinct pattern. At a TiC loading of 2 wt%, TiC exhibited a dispersed distribution. Interestingly, in coatings loaded with 4 wt% TiC, TiC was observed in various shapes, including elongated, square, petaled, and circular forms owing to the melting of TiC particles under the influence of a high-energy laser beam. The convection action of the molten pool combined several unmelted, partially melted, and precipitated TiC particles, resulting in diverse shapes. Furthermore, increasing the TiC content to 10 wt% led to the aggregation and fusion of TiC into clusters. Additionally, the electrochemical corrosion resistance behavior of CrMnFeCoNi coatings with varying TiC content displayed a significant correlation with the TiC concentration. As the TiC content increased, the galvanic corrosion resistance also increased. At lower TiC content levels, a higher number of electrochemical cells formed between the CrMnFeCoNi matrix and the dispersed TiC, leading to an elevated corrosion rate. In contrast, as the TiC content increased, the dispersed TiC phase fused together, reducing the likelihood of electrochemical cell formation. Notably, the electrochemical corrosion resistance of the CrMnFeCoNi coating containing 10 wt% TiC resembled that of the TiC-free coating.

Reactive hot pressing parameters on reaction, densification, and mechanical properties of Ti3AlC2 ceramic

AbstractTi3AlC2 ceramic was produced using a 3Ti–Al–1.8C powder mixture by reactive hot pressing at 2–10 MPa and 1100°C–1300°C for 15–60 min. X‐ray diffraction patterns confirmed the Ti2AlC phase up to 1200°C, and at 1300°C, Ti3AlC2 remained as a primary phase with a tiny peak of TiC. Ti3AlC2 and TiC phases varied from 93 to 96 vol.% and 7 to 4 vol.%, respectively, with different pressure and time at 1300°C. An applied pressure of 10 MPa and 1300°C resulted in a density of 4.18 g/cm3 (98.4% relative density) in the samples. It was observed that lower temperature (1100–1200°C) and low applied pressure (2 MPa) do not attain the required density, whereas soaking time is insignificant to achieve the required density at 1300°C. The microhardness and flexural strength were 6.32 ± .20 GPa and 592 ± 42 MPa, respectively.

Evaluation of reactive wetting kinetics of carbon fibers by molten Al-Ti alloy and its application to the fabrication of Al/carbon fiber composites

Wetting and interfacial reactions between molten Al and carbon fibers (CFs) are crucial for the fabrication of high-thermal conductive Al/CF composites through liquid-state processes including casting. The formation of Al4C3 which has a low thermal conductivity and high reactivity with water needs to be suppressed while improving wettability. The addition of Ti into molten Al forms TiC and contributes to significant improvement in wettability. To control a thin morphology of TiC, the kinetics of reactive wetting need to be clarified. In the present study, the reactive wetting kinetics between molten Al or Al-Ti alloy and pitch-based CF were investigated using the dipping coverage method combined with microstructural observations. The addition of Ti into molten Al drastically accelerated the wetting and reduced the apparent activation barrier for reactive wetting, which was related to the change in the interfacial products from the Al4C3 phase to the TiC phase. The Al4C3 phase grew while eroding the CFs, whereas the TiC phase formed in a thin-layered morphology around CFs and suppressed the diameter reduction of CF. The reduction in the apparent activation barrier and the morphology of carbides indicated a change in the dominant phenomena for reactive wetting from Al4C3 growth to TiC formation (controlled by diffusion in liquid Al). Based on the kinetics evaluations, CF were hybridized with pure Al and Al-Ti alloy through a casting process, and their thermal conductivities were evaluated. The addition of CF into pure Al degraded the thermal conductivity due to the eroded CF and coarsened Al4C3 phase, whereas the addition of CF into Al-Ti alloy enhanced the thermal conductivity. This study provides new insights into reactive wetting phenomena related to the fabrication of high-thermal conductive metal matrix composites.

L12-(Al,Si)3Ti + TiC hybrids reinforced laser welded SiCp/2A14Al joint with extraordinary strength

The interfacial reaction 3SiC + 4Al → Al4C3 + 3Si has bottlenecked the fusion welding of aluminum matrix composites for decades, hindering further improvement of the mechanical properties of high-strength lightweight SiCp/Al joints. Using unweldable SiCp/2xxxAl as an experimental model, we designed a targeted reinforcing phase that can be alloyed in situ with Si and C elements. L12–(Al,Si)3Ti and TiC were generated in situ from Si and C precipitated from SiC particles. In addition, the in situ-formed Al3Ti adhered to the surface of the SiC particles, enhancing the load transfer of the alloy film during the tensile process. The mechanism of titanium on the joint grain nucleation and refinement and the contribution of each strengthening mechanism to mechanical properties were discussed in detail. Quantitative calculations showed that the combined effects of the nanoscale TiC phase (Orowan strengthening) and high density of the geometrically necessary dislocations (dislocation strengthening) increase the yield strength of the joints. The ultimate tensile strength of the joint was 393 MPa (with a strength coefficient of 83%), which was highly comparable to that of SiCp/Al joints prepared by friction stir welding. This work provides fundamental guidance for the welding of high-strength SiCp/2xxxAl alloy.

Fine study of hierarchical interphase constructed by Ti3SiC2 and carbon nanotubes in SiCf/SiC composites

The interphase in silicon carbide fiber-reinforced silicon carbide ceramic matrix composites (SiCf/SiC) assumes a significant role in the mechanical properties exhibited at elevated temperatures. The strength, toughness, and chemical stability of a composite is frequently influenced by the optimization of its interphase. In this work, the MAX phase (Ti3SiC2) and carbon nanotubes (CNTs) were successively deposited on the SiCf using the molten salt method and chemical vapor deposition technique, respectively, to create a hierarchical structure. Transmission electron microscopy was employed to undertake a comprehensive investigation of the interfacial component in SiCf/SiC composites. The detailed study of interphases in SiCf/SiC composites has been conducted through the analysis of crystallization, the bonding natures, and the micromorphology, encompassing geometry and constituent characteristics. A bilayer consisting of TiC–Ti3SiC2/Ti5Si3 and a vertical array of carbon nanotubes (CNTs) with a length of 7 μm is fabricated on the surface of SiCf/Ti3SiC2-CNTs. The SiCf/Ti3SiC2/SiC and SiCf/Ti3SiC2-CNTs/SiC composites exhibit lamellar structures of Ti3SiC2, which indicates a further crystallization of Ti3SiC2 resulting from the formation of SiC matrix by PIP procedure. The interphase of SiCf/Ti3SiC2-CNTs/SiC composite may be categorized into four distinct layers: a TiC phase, a TiSi2 phase, a transition phase of TiSi2/TiC, and a Ti3SiC2 phase. This interphase structure is more intricate compared to the interphase structure observed in the SiCf/Ti3SiC2/SiC composite. This research indicates significant value for the future design and optimization of interfaces.

Solid-state reaction mediated microstructural evolution in a spark plasma sintered in situ Ti–B4C composite

A novel porosity-free in situ Ti–B4C composite was fabricated via spark plasma sintering (SPS). Detailed analysis of the phase evolution, coupling results from XRM, XRD and SEM-EBSD-EDS, indicate that primarily TiB2 precipitates formed due to the in-situ reactions between the boron-carbide and titanium powders. The precipitation of TiB2 resulted in the formation of a graphitic C-rich thin layer circumscribing the partially reacted B4C particles. Further progression of the in-situ reaction leads to the out-diffusion of the excess carbon from the B4C particles, across the graphite and TiB2 phases, forming TiC upon reacting with the titanium matrix. Therefore, the final microstructure primarily consisted of TiB2, TiC, and partially reacted B4C phases, with small amounts of TiB, α-Ti, and graphite. Furthermore, the microstructure in these SPS processed in situ composites appeared to be the product of a solid-state Ti–B4C diffusion couple, substantially different from their fusion-based additively manufactured counterparts. Nano-indentation tests revealed a remarkably high average hardness of ∼25 GPa for this SPS-processed Ti–B4C composite and comparable (with literature) phase-specific hardness and modulus values for the constituent TiB2, TiC, and B4C phases.

Investigation and production of non-cytotoxic TixNbxSn (x = 5,10,15,20) alloys by high-energy mechanical milling with antibacterial activity

In this research, TixNbxSn (x = 5, 10, 15, 20 wt%) alloys were produced by high-energy mechanical alloying, and their potential applications as biomaterial were investigated through the microstructural characterizations (via XRD, SEM, and EDS analyses), mechanical tests (via hardness and elastic modulus tests), and biological studies (via antibacterial and cytotoxic tests). The alloying studies were carried out at room temperature in a high-energy ball milling for 8 h followed by a consolidation using a uniaxial pressing and 2 h pressureless sintering at 1150 °C. The XRD and EDS analyses showed that α-Ti, β-Ti, and TiC phases were present in the microstructure after sintering at high-temperature. Hardness tests revealed a wide range of values between 384 and 723 HV depending on the alloy compositions. That is, the volume fraction of TiC phase formed during processing and the ratio of α-Ti/β-Ti phases appear to control the hardness of the alloys. The elastic modulus was determined ranging from 70 to 103 GPa as a function of compositions with Ti15Nb15Sn alloy having the closest elastic modulus to the bone. The biological investigations revealed that TiNbSn alloys exhibited antibacterial properties against Staphylococcus aureus (S. aureus) and were not cytotoxic to healthy cells, regardless of their compositions. Furthermore, the findings indicated that when the cells were subjected to various dilutions of alloy extracts, there was a noticeable enhancement in both cell proliferation and viability. These findings have the potential to pave the way for novel approaches in the creation of TiNbSn alloys as biomaterials.

Microstructure and properties of TiC–Ti5Si3 reinforced copper matrix composites

In this study, Ti5Si3 single-phase and TiC–Ti5Si3 hybrid phases reinforced copper matrix composites with different volume fractions were prepared by melt reaction. The microstructures and mechanical properties of the composites were analyzed to investigate their wear and tensile mechanisms. The wear resistance of the composite materials exhibits a non-linear behavior with increasing load, initially decreasing and then increasing, reaching its lowest point at 7.35 N. At higher loads, such as 9.8 N, the composites form a more stable and effective wear-resistant layer, exhibiting the positive impact of the reinforcing phase on wear resistance. Furthermore, as the content of the reinforcing phase increases, the brittleness of Ti5Si3 also increases, along with the expansion of the interface between the reinforcing phase and the matrix. This results in a transition of the wear mechanism from delamination wear to abrasive wear and an increased likelihood of spalling under shear forces. Therefore, the composite material achieves optimal wear resistance when the Si content is at 1%. In addition, the TiC and Ti5Si3 phases within the Cu matrix not only effectively bear the load but also impede crack propagation, resulting in a shift in the fracture mode of the composites from ductile fracture to cleavage fracture or quasi-cleavage fracture as the reinforcement content increases. Finally, hot rolling proves to be an effective method for refining the reinforcement and improving its uniformity, leading to significant enhancements in tensile strength and ductility. However, the reinforcement causes a disruption in the continuity of the matrix, resulting in a reduced elongation in the composite material with a Si content of 1% after the hot rolling process.

WEAR-RESISTANT POWDER MATERIALS FOR PLASMA-POWDER SURFACING

Among powder surfacing materials with high hardness and resistance to abrasive wear, powders based on WC-TiC-Co systems, which are the basis of hard alloys, are among the most promising. (Research purpose) The research purpose is investigating wear-resistant powder materials for plasma-powder surfacing by electrodispersing solid alloy waste of the T30K4 brand in kerosene. (Materials and methods) We chose substandard carbide plates of the T30K4 brand as the starting material; lighting kerosene as the working fluid. We solved the tasks set in the work on the study of the composition, structure and properties of the obtained carbide powders using modern equipment and complementary methods of physical materials science. Electrodispersion of solid alloy waste was carried out on the original installation; the shape and morphology of the particle surface were studied on an electron-ion scanning microscope with field emission of electrons QUANTA 600 FEG; particle size composition ‒ on a laser particle size analyzer Analysette 22 NanoTec; X-ray spectral microanalysis of particles was carried out on an energy dispersive X-ray analyzer of EDAX company, integrated into a scanning electron microscope QUANTA 200 3D; phase analysis of particles was performed on an X-ray diffractometer Rigaku Ultima IV. (Results and discussion) A new technology for producing a carbide electroerosive powder suitable for plasma-powder surfacing has been developed and investigated, the effectiveness of which is confirmed by the properties of the proposed powder material: the spherical shape of powder particles; the average size of powder particles is 58.4 micrometers; powder particles with a uniform distribution of alloying elements: C, Co, Ti and W; powder particles include phases of carbides WC and TiC. (Conclusions) The conducted studies have shown that it is possible to obtain a wear-resistant powder alloy with a uniform distribution of alloying elements by the method of electroerosive dispersion of solid alloy waste of the T30K4 brand.

IMPROVING THE EFFICIENCY OF RESTORATION AND HARDENING OF THE WORKING BODIES OF TILLAGE MACHINES BY PLASMA-POWDER SURFACING OF CARBIDE ELECTROEROSIVE MATERIALS

The use of powders obtained from solid alloy waste as a highly solid dispersed component of the composition for plasma-powder surfacing will improve the quality, reliability and durability of plasma coatings of working bodies of tillage machines with a minimum of costs for powder materials. However, the properties of these plasma coatings have not been studied enough, so it is necessary to conduct comprehensive studies. (Research purpose) The research purpose is improving the technology of restoration and hardening of the working bodies of tillage machines by plasma-powder surfacing of powder materials obtained by electroerosive dispersion of solid alloy waste T30K4. (Materials and methods) Carbide powders made by electrodispersing solid alloy waste T30K4 in kerosene were used to obtain plasma coatings. We chose for the renovation object a pointed cultivator paw made of 40XC rolled steel. The obtained plasma coatings were studied using modern equipment and complementary methods of physical materials science. (Results and discussion) We have developed, tested and investigated a new technology for restoring and strengthening the working bodies of tillage machines using the example of a pointed cultivator paw by plasma-powder surfacing of carbide electroerosive powder materials. The effectiveness of the development was confirmed by the properties of plasma coatings: the microstructure of the coating has a fine-grained structure, without inclusions, uniform phase distribution and the absence of pores, cracks and discontinuities; elements W, Ti and Co in the coating are evenly distributed; phases of carbides WC and TiC are present; the grain size of the coatings is about 0.3 micrometers; the microhardness of the coatings is about 14245 megapascals. (Conclusions) The results of field tests showed that the resource of the working bodies of tillage machines, restored and strengthened with carbide electroerosion materials, is 1.25 times higher than the resource of new parts.