Distribution Of TiC Particles Research Articles

Effects of TiC content on microstructure, mechanical properties, and thermal conductivity of W-TiC alloys fabricated by a wet-chemical method

W-(0–0.9)TiC (wt.%) alloys were prepared by a wet-chemical method and spark plasma sintering. The effects of TiC content on the microstructures, mechanical properties, and thermal conducting properties of the prepared W-TiC alloys were investigated. The results revealed that the average grain size of the W-(0–0.9)TiC alloys decreased, and their average TiC particle size increased with the increase of TiC content. The bending fracture strengths of the prepared samples increased significantly with increased TiC content in the range of 0–0.5%, which was attributed to the uniform distribution of TiC particles with a high proportion located in the tungsten grain interiors. The W-0.5TiC alloy exhibited the best mechanical properties with the highest relative density, bending strength, and flexural strain of 97.61%, 1065.72MPa, and 1.23%, respectively. Moreover, the thermal conductivities of the W-(0.1–0.5)TiC alloys were slightly lower than those of pure tungsten at all testing temperatures. However, the mechanical properties and thermal conducting properties of the W-0.7TiC and W-0.9TiC alloys were significantly deteriorated due to the non-uniform aggregation of TiC particles at the tungsten grain boundaries.

Microstructures, Mechanical Properties and Thermal Conductivities of W-0.5 wt.%TiC Alloys Prepared via Ball Milling and Wet Chemical Method

Two kinds of W-0.5 wt.%TiC alloys were prepared, one by ball milling and the other by the wet chemical method. For comparison, pure tungsten powders were chemically prepared and sintered by the same process. The microstructures, mechanical properties and thermal conductivities of the prepared samples were characterized. It has been found that the wet chemical method resulted in finer sizes and more uniform distribution of TiC particles in the sintered tungsten matrix than the ball milling method. The W-TiC alloy prepared by the wet chemical method achieved the highest bending strength (1065.72 MPa) among the samples. Further, it also exhibited obviously higher thermal conductivities in the temperature range of room temperature to 600°C than did the W-TiC alloy prepared by ball milling, but the differences in their thermal conductivities could be ignored in the range of 600–800°C.

Thermal monitoring of microstructure and carbide morphology in direct metal deposition of Fe-Ti-C metal matrix composites

Abstract In this paper, real-time cooling rate of Fe-Ti-C Metal Matrix Composites (MMCs) made by Direct Metal Deposition (DMD) are measured to monitor microstructure and carbide morphology. This research proves that carbide morphology developed by DMD of Fe–TiC composite coating on AISI 1020 carbon steel is highly affected by cooling rate and pre-heat. For this purpose, the DMD process is monitored by a thermal camera to obtain real-time values of the cooling rate resulted from a range of selected scan speeds. Two approaches are studied for the single-track depositions: (a) single speed and (b) dual speeds in which the scan speed changes during the deposition. The dual speed generates different preheat values during deposition and thus deviates the cooling rate. Consequently, the effect of cooling rate and preheat temperature are studied on carbide morphologies. Results show that scan speed plays the main role in the formation and distribution of TiC particles in the deposited layer by affecting the cooling rate and dilution (melt pool composition). Based on this research, it is possible to control the cooling rate in order to achieve specific carbide morphologies in the deposited layer. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used to characterize the deposited layers' microstructure.

Effect of Ultrasonic Stirring on Changes in Microstructure and Mechanical Properties of Cast In­situ Al 5083 alloy Composites Containing 5wt.% and 10wt.% TiC particles

The effect of ultrasonic stirring on changes in microstructure and mechanical properties of Al 5083 and Al 5083-TiC composites have been studied. The TiC particles in the composite was 5 and 10 wt.%. Primarily, in-situ Al 5083-TiC composite was synthesized using self propagating high temperature synthesis process using casting route. Al 5083+20TiC master composite was prepared by the mechanical alloying of Al 5083 powder, Titanium powder (<45 μm) and Graphite powder (<10 μm) powders in a planetary ball mill followed by cold compaction. The cold compacted Pellets of master composite were added in the Al 5083 melt under argon atmosphere. The concentration of TiC varied between 0 to 10 wt.% of alloy. the microstructure of the aluminum alloy and the composites containing TiC homogeneous and fine grain in the matrix and uniform distribution of TiC particles in Al alloy matrix. the composite prepared ultrasonic stirring improved mechanical properties (compressive strength and hardness) as compare to the one prepared without ultrasonic stirring. Further the ultrasonically stirred alloy and composites found refined microstructure. Result in the improvement of mechanical properties.

The Role of Friction Stir Processing (FSP) Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP), has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight) were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

Microstructure and properties of in-situ synthesized Cu-1 wt%TiC alloy followed by ECAP and post-annealing

A dispersion-strengthened copper alloy with 1wt% TiC for commercial electrical-contact wires was prepared by in-situ reaction casting, grain-ultrafining by equal-channel angular pressing (ECAP) and subsequent annealing with aim to obtain excellent comprehensive performance. The results showed that fine TiC particles were in-situ synthesized in the as-cast Cu matrix and aggregated in clusters, and thus mechanical properties of the as-cast alloy deemed insufficient. Continued ECAP at 473K significantly refined the grains of the as-cast alloy and improved the distribution of TiC particles. Due to multiple strengthening mechanisms, the ECAP-processed alloys maintained good conductivity with obviously enhanced tensile strength and hardness values. After post-ECAP annealing, the elongation and conductivity of the fine-grained copper alloy increased with the adequate tensile strength. The novel combined process endows the alloy appropriate performance to serve current high-frequency electrification railway systems.

Sliding Wear Behavior of TiC-Reinforced Cu-4 wt.% Ni Matrix Composites

The present investigation explores the effect of TiC content on the sliding wear properties of Cu-4 wt.% Ni matrix composites. Cu-4 wt.% Ni − x wt.% TiC (x = 0, 2, 4 and 8 wt.%) metal matrix composites were developed by powder metallurgy route. Their friction and wear was studied under dry sliding at different loads of 5, 7.5 and 10 N and constant sliding speed of 2 m/s using a pin-on-disk machine. The metallographic observations showed an almost uniform distribution of TiC particles in the matrix. Hardness of the composites increased with increasing TiC content (up to 4 wt.%). Friction and wear results of TiC-reinforced composites show better wear resistance than unreinforced matrix alloy. However, the optimum wear resistance was observed for 4 wt.% TiC-reinforced composites. Worn surfaces of specimens indicated the abrasion as the primary mechanism of wear in all the materials investigated in the study. The observed behavior has been explained on the basis of (1) the hardness which results in a decrease in real area of contact in composites containing TiC particles and (2) the formation of a transfer layer of wear debris on the surface of the composites which protects underlying substrate by inhibiting metal-metal contact.

Fabrication and characterization of Ti6Al4V/TiB2–TiC composites by powder metallurgy method

Titanium matrix (Ti6Al4V) composites reinforced with TiB2 and TiC were produced through powder metallurgy method. The effect of addition of both TiB2 and TiC with different contents (2.5 wt%, 5.0 wt% and 7.5 wt%) on the density, microstructure and hardness properties of titanium matrix was investigated. The size distributions of the matrix alloy and reinforcement particles were measured by particle size analyzer. Microhardness of the sintered composites was evaluated using Vickers’s hardness tester with a normal load of 3 N and a dwell time of 10 s. Ti6Al4V alloy and Ti6Al4V/TiB2–TiC composites were characterized through X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) equipped with energy-dispersive spectrometer (EDS). The addition of TiB2 and TiC particles enriches the properties of Ti6Al4V alloy. The sintered Ti6Al4V/TiB2–TiC composite features a dense and pore-free microstructure with varying TiB2 and TiC particle distribution in the metal matrix. The results of this study show that the development of new phases plays a significant role in the properties of these composite materials.

Mechanical Properties of Copper-TiC &lt;i&gt;In Situ&lt;/i&gt; Metal Matrix Composite

Copper based TiC reinforced in-situ metal matrix composite was synthesized by melting copper, hexaflurotitanate and graphite powder in appropriate proportion at a temperature of 1100 °C using stir casting technique. Both copper matrix and copper-TiC composite were subjected to microstructure studies, x-ray diffraction analysis, hardness and tensile test. Optical micrograph shows fine and uniform distribution of TiC particles throughout the matrix. X-ray diffraction analysis confirms the formation of Titanium carbide particles. Developed composite exhibit a significant improvement in hardness and ultimate tensile strength compared with unreinforced copper.

Fabrication of Al–TiC composites by hot consolidation technique: its microstructure and mechanical properties

Al-based metal matrix composites reinforced with different volume fraction of TiC particles as reinforcement was synthesized by the hot consolidation process. The titanium carbide used in this study was synthesized directly from the titanium ore (ilmenite, FeTiO3) by carbothermic reduction process through thermal plasma technique. The field emission scanning electron micrographs (FESEM) reveals the homogeneous distribution of TiC particles in the Al-matrix. Enhanced Young's modulus and mechanical properties with appreciable ductility were observed in the composite samples. The significant increases in the mechanical properties of the composites demonstrate the effectiveness of the low-density TiC reinforcement.

Effect of nano-sized TiC particle addition on microstructure and mechanical properties of SA-106B carbon steel

The dispersion behavior of nano-sized TiC particles treated by different processes and its influence on microstructural and mechanical modification has been investigated in SA-106B carbon steel with different TiC contents. It was found that mechanically-activated TiC nanoparticles introduced into a carbon steel matrix were dissolved during hot rolling and re-precipitated vigorously during subsequent normalizing treatment at 920°C. The dispersed TiC particles were very fine (<20nm), giving a suppressing effect on the growth of recrystallized austenite to promote considerable grain refinement of final ferrite–pearlite structure. This fine microstructure (grain size: ~10μm) with a homogeneous distribution of TiC particles offers a higher strength level (yield strength: 372MPa, tensile strength: 544MPa) without sacrificing ductility (>30%) and impact energy (>250J) at the TiC content of 0.1wt%. Theoretical calculations showed that grain refinement plays a dominant role in enhancing the yield strength of TiC-bearing carbon steel, together with nanoparticle strengthening interacting on the solid solution strengthening and dislocation strengthening.

Effect of Tool Rotational Speed on Microstructure and Microhardness of AA6082/TiC Surface Composites using Friction Stir Processing

Friction stir processing (FSP) is as a novel modifying technique to synthesize surface composites. An attempt has been made to synthesis AA6082/TiC surface composite using FSP and to analyze the effect of tool rotational speed on microstructure and microhardness of the same. The tool rotational speed was varied from 800 rpm to 1600 rpm in steps of 400 rpm. The traverse speed, axial force, groove width and tool pin profile were kept constant. Scanning electron microscopy was employed to study the microstructure of the fabricated surface composites. The results indicated that the tool rotational speed significantly influenced the area of the surface composite and distribution of TiC particles. Higher rotational speed provided homogenous distribution of TiC particles while lower rotational speed caused poor distribution of TiC particles in the surface composite. The effect of the tool rotational speed on microhardness is also reported in this paper.

Influence of Traverse Speed on Microstructure and Mechanical Properties of AA6082-TiC Surface Composite Fabricated by Friction Stir Processing

Friction stir processing (FSP) has evolved as a novel solid state technique, for refinement of microstructure, enhancement of mechanical properties and fabrication of aluminium matrix composites (AMCs). In this work, AA6082/TiC surface AMC was produced by FSP technique and the effect of traverse speed on microstructure and mechanical properties were investigated. The traverse speed was varied from 40mm/min. to 80mm/min. in steps of 20mm/min. The rest of the process parameters such as groove width, tool rotational speed and axial force were kept constant. Micrographs of the AA6082/TiC AMCs were obtained using optical microscope and scanning electron microscope. Microhardness and wear behaviour of the surface composites were analysed. Results revealed that the traverse speed significantly influenced the area of surface composites, dispersion of TiC, grain size of matrix, microhardness, and wear rate of the AA6082/TiC AMCs. The traverse speed was inversely proportional to the area of surface composites. The homogenous distribution of TiC particles was attained with lower traverse speed, whereas poor distribution of TiC particles was influenced by the higher traverse speed. Also increase in the traverse speed of the surface composite enhanced microhardness and reduced the wear rate when compared with lower traverse speed.

Production and Wear Characterization of AA6082 -TiC Surface Composites by Friction Stir Processing

Friction stir processing (FSP) has originated to be an innovative solid state technique to fabricate aluminium matrix surface composites (AMCs). FSP technique was used to produce AA6082/TiC surface AMCs and analyze the effect of TiC particles on microstructure and dry sliding wear behaviour. Surface AMCs containing five different various volume fractions (0, 6%, 12%, 18% and 24%) were fabricated. FSP was carried out using a tool rotational speed of 1200rpm, travel speed of 60mm/min and an axial force of 10kN to produce surface composite. The microstructure of the AA6082/TiC AMCs was studied using optical and scanning electron microscopy (SEM). The sliding wear behaviour was evaluated using a pin-on-disk apparatus. The results revealed that the TiC particles significantly influenced the distribution of TiC particles, and sliding wear behaviour of the AA6082/TiC AMCs. The effect of TiC particles on worn surface is also reported in this paper.

Fabrication of Fe-TiC Composite by High-Energy Milling and Spark-Plasma Sintering

Fe-TiC composite was fabricated from Fe and TiC powders by high-energy milling and subsequent spark-plasma sintering. The microstructure, particle size and phase of Fe-TiC composite powders were investigated by field emission scanning electron microscopy and X-ray diffraction to evaluate the effect of milling conditions on the size and distribution of TiC particles in Fe matrix. TiC particle size decreased with milling time. The average TiC particle size of 38 nm was obtained after 60 minutes of milling at 1000 rpm. Prepared Fe-TiC powder mixture was densified by spark-plasma sintering. Sintered Fe-TiC compacts showed a relative density of 91.7~96.2%. The average TiC particle size of 150 nm was observed from the FE-SEM image. The microstructure, densification behavior, Vickers hardness, and fracture toughness of Fe-TiC sintered compact were investigated.

Effect of Laser Cladding Al&lt;sub&gt;3&lt;/sub&gt;Ti-Based Coatings on the Wear and Corrosion Resistances of AA6063 Aluminum Alloy

Al3Ti-based intermetallic compound coatings were formed on AA6063 aluminum alloy by laser cladding. The microstructure, wear and corrosion behaviors were investigated. The results showed that, the laser cladding coatings were made up of Al3Ti dendrites, interdendritic α-Al and uniform distribution of TiC particles, and showed good bonding to the substrate. The microhardness, wear and corrosion resistances of the laser cladding coatings greatly increased compared to the substrate. And with the addition of TiC particles to the coating, the superficial properties are improved simultaneously.

Microstructure and microhardness of AA1050/TiC surface composite fabricated using friction stir processing

Friction stir processing (FSP) has been developed by several researchers to produce an upper surface modification of metallic materials. The fabrication of TiC particulate (~2 \(\upmu \)m) reinforced aluminum matrix composite (AMC) using FSP is studied in this paper. The measured content of TiC powders were compacted into a groove of 0.5 mm × 5.5 mm. A single pass FSP was carried out using a tool rotational speed of 1600 rpm, processing speed of 60 mm/min and axial force of 10 kN. A tool made of HCHCr steel, oil hardened to 62 HRC, having a cylindrical profile was used in this study. The microstructure and microhardness of the fabricated AMC were analysed. Scanning Electron Microscope (SEM) micrographs revealed a uniform distribution of TiC particles which were well-bonded to the matrix alloy. The hardness of the AMC increased by 45% higher than that of the matrix alloy.

In Situ Production of Fe-TiC Nanocomposite by Mechanical Activation and Heat Treatment of the Fe2O3/TiO2/C Powder

In this study, Fe-TiC nanocomposite was synthesized by carbothermic reduction of activated Fe2O3, TiO2, and graphite powder mixture. The effect of 0, 5, and 20 h of high energy ball milling of mixture on the reduction process was also investigated. Comparing the results of the thermogravimetry analysis of milled and un-milled mixtures clearly showed that the reduction temperature decreased due to the milling process. XRD pattern of 20 h milled powder mixture proved that Fe-TiC nanocomposite was formed after the heat treatment of activated powder at 1100°C for 1 h under vacuum. The microstructure studies of the milled mixture by scanning electron microscope revealed homogenous distribution of TiC particles in the Fe matrix.

Development in Wear Resistance of Fe-0.7Cr-0.8Mn Milling Balls through &lt;i&gt;In Situ&lt;/i&gt; Reinforcing with Low Weight Percent TiC

In order to increase wear resistance of Fe-0.7Cr-0.8Mn cold work tool steels, low weight percentage of Ti incorporated to the alloy and subsequently, because of high affinity between additive titanium and carbon content in this alloy, low weight percentage of TiC in situ formed in matrix. These composites can be used as the milling balls in mining and cement industries because of their improved wear resistance. Formation, shape, size and distribution of TiC particles within the matrix were studied by optical microscopy equipped with image analyzer, optical emission spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. Also microhardness and density of the samples measured. Abrasion wear tests were carried out using a pin on disc type machine. An experimental design based on Taguchi method was applied to investigate the effect of TiC content, applied load, sliding distance and roughness of SiC abrasive paper on wear behavior of samples. The results show that by reinforcing the Fe-0.7Cr-0.8Mn steels with low weight percentage of TiC, wear resistance of these kind of milling balls significantly increases. Sliding distance has the most influence on wear rate of samples, also weight loss of samples decreases as sliding distance, applied load and roughness of grinding decreases.

Thermal shock response of fine- and ultra-fine-grained tungsten-based materials

In this work, the focus is on the thermal shock analysis of fine- and ultra-fine-grained tungsten-based materials doped with 0.5–1.1 wt% TiC that showed in previous studies improved ductility at low temperatures and also performed well when exposed to neutrons and ions (H/He). Herein, the resistance of the material to crack formation is evaluated by applying edge-localized mode-like loads (n=100) with an energy density of 1 MJ m-2 at various temperatures up to 150 °C by means of an electron beam facility. The results indicate that the cracking threshold is significantly reduced even down to room temperature when the oxygen content is reduced and the combination of grain size, TiC particle size and distribution of TiC-particles to almost each grain boundary reaches its optimum. This is achieved by a post-manufacturing treatment of the material at 1650 °C using the material's superplasticity caused by grain boundary sliding at this temperature, which changes the material's microstructure from ultra-fine grains surrounded by weak grain boundaries to fine grains with significantly strengthened grain boundaries.