Addition Of TiB2 Research Articles

Effect of boron carbide composition on its densification behavior during spark plasma sintering (SPS)

The effect of boron carbide composition on its sintering behavior was investigated. Boron carbide of various compositions was synthesized by reacting stoichiometric boron carbide with TiO2. Titanium oxide was reduced by carbon that originated in stoichiometric boron carbide, leads to a decrease its carbon content and the formation of TiB2 phase. Powder mixtures containing boron carbide of various boron to carbon ratios (x in BxC was changed from 4.05 to 6.33) and different vol% of TiB2 (from 6 to 21 vol%) were synthesized and densified by spark plasma sintering at 1800 and 1900 °C under an uniaxial pressure 50 MPa for 30 min. A mixture of stoichiometric boron carbide with 20 vol% TiB2 was densified under the same conditions. The positive effect of boron carbide composition on the sintering behavior was clearly observed, while only minor effects of TiB2 addition were detected. It was established that the carbon concentration in boron carbide gradually decreased in the 1200–1700 °C temperature range during spark plasma sintering and after sintering at 1800 and 1900 °C when the B to C ratio (x) was already close to its stoichiometric value, regardless of the initial carbon content. Mechanical properties of the sintered samples reflected their relative density. The maximum values of Young’s modulus (450 ± 10 GPa), bending strength (840 ± 40 MPa) and hardness (35 ± 4 GPa) were obtained for fully dense specimens fabricated from the synthesized B6.3C-21vol%TiB2 mixture.

Microstructure and Wear Properties of T6 Heat Treated Semisolid A356-TiB2 composite

The aim of this study is to investigate the microstructure and wear properties of T6 heat treated semisolid A356 composite containing 1.5 wt.% and 2.63 wt.% TiB2. The semisolid A356-TiB2 composite was prepared using a cooling slope casting technique. The sample, then was solution treated at different temperatures (500°C, 520°C and 540°C) for 5 hours soaking time. Then, age hardening was conducted at different temperatures (120°C, 150°C and 180°C) for 8 hours. Semisolid A356 composite was characterized for microstructure, microhardness and wear properties. Microstructure of semisolid A356 composite was refined with a higher amount of TiB2. High solution treated temperature (540°C) resulted in the finer size of Si particles in the semisolid A356 alloy. Microhardness of solution treated semisolid A356 alloy achieved higher hardness at 540°C with a hardness value of 75.16 HV. Solution treated of semisolid A356 composite containing 1.5 wt.% TiB2 has the smallest Si particles and the highest hardness of 119.7 HV. Among the samples, A356-1.5 wt.% composite after aging at 180°C showed the highest hardness (129.7 HV). Wear resistance of semisolid A356 alloys was improved by the addition of TiB2. Wear surface morphology revealed that the adhesive and abrasive wear mechanism present.

Effects of TiB2 particles on artificial aging response of high-Li-content TiB2/Al-Li-Cu composite

The effect of TiB2 particles on artificial aging response of cast high-Li-content TiB2/Al-Li-Cu composite at 175 °C was investigated for the first time by a combination of various techniques, including transmission electron microscopy (TEM), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). We discovered that the nano-sized particles, in the shapes of hexagonal or equaixed, had a strong influence on mechanical properties and microstructural evolution during artificial aging process. With the introduction of TiB2 particles, the average grain size decreased significantly. The precipitations of θ′ and T1 precipitates were promoted in the reinforced composite, however, there was no obvious difference in the size and number density of δ′ precipitates between the unreinforced alloy and reinforced composite. DSC results showed that the addition of TiB2 did not change the precipitation sequence, although both precipitation and dissolution kinetics were altered. The reinforced composite revealed a remarkable improvement in mechanical properties.

Effect of Al-TiB Addition on the Mechanical Properties and Microstructure of Al-ADC12/NanoSiC Produced by Stir Casting Methods

Addition of Ti-B grain refiner in Al-ADC12/nanoSiC composite results in improvement of tensile strength, hardness, and wear resistance through grain refinement. In this research, composite of Al-ADC12/nano SiC (0.15 %vf) with variations of TiB respectively (0.0), (0.02), (0.04), (0.06), dan (0.08) wt% were produced by stir casting. 10% of Mg were added to promote wettability between reinforce and matrix. It was found the best addition of TiB is 0.04 wt% Ti-B which results 135,9 MPa in tensile strength, 46 HRB in hardness, and 1.47x10-5 mm3/s as wear rate. The increase in mechanical properties of composites mainly because of Al3Ti acts as nucleants which initiates the grain refinement and the existence of MgAl2O4 phase indicates an interphase between nano SiC and ADC12 matrix. However, the increase of Ti-B addition after optimum number gives no significant results. High composition of iron and magnesium addition will form intermetallic phase β-Fe, π-Fe, and Mg2Si.

Mechanical properties enhancement and microstructure study of Al-Si-TiB2 in situ composites

Al–Si alloy-based composite is one of the most promising MMC materials owing to its outstanding mechanical properties, wear and corrosion resistance, low cost and ability to be synthesized via conventional casting routes. Challenges in achieving clean interface between reinforced particles and matrix alloy have been overcome by means of in-situ techniques of fabrication. Present investigation is concerned with synthesizing Al-Si-TiB2 in-situ composites through stir casting route using K2TiF6 and KBF4 halide salts for exothermic salt metal reaction. X-Ray diffraction analysis revealed the existence of TiB2 in the prepared samples. Effect of TiB2in-situ particles in the Al-Si base alloy has been investigated from the results obtained from optical microscopy as well as SEM study and wear analysis with a pin on disc wear testing apparatus. Improved hardness and wear properties were observed with addition of TiB2.

Microstructure and Tribological Performance of TiB2-NiCr Composite Coating Deposited by APS

Nickel chromium (NiCr) powders with different titanium diboride (TiB2) additions (20, 40 and 60 wt %) were prepared with a mechanical alloying method and then sprayed using an air plasma spraying technology. The microstructure and phase composite of the powders and the cross-sections of deposited coatings were analyzed with a scanning electronic microscope and X-ray diffraction. The tribological performance of the coatings was studied using a pin-on-disk tribometer at room temperature. The weight loss of the as-sprayed coating was measured by using a high accuracy weighing balance. Cr3C2-25NiCr coating was produced and tested for comparison. The morphologies of the worn surface were then investigated. Parts of debris with some scratches were found, presenting typical signs of abrasive wear and showing slight adhesive wear on the surface. The 20 wt % additive TiB2 coating demonstrated the highest microhardness and the lowest coefficient of friction. The wear resistance of the metal-ceramic composites coatings was enhanced with the addition of TiB2.

Characteristics of the Nial/Ni3al Matrix Composite With Tib2 Particles Fabricated By High Pressure – High Temperature Sintering

AbstractThe article presents the results of tests carried out on the manufactured composite materials based on a two-phase NiAl/Ni3Al matrix, which was enriched with the addition of TiB2ceramic particles added in an amount of 4 and 7 vol%. The resulting mixtures were sintered by the High Pressure High Temperature (HP-HT) process. The results were compared to the results obtained for the sole matrix material produced under the same conditions. It has been shown that, at a lower density, the addition of reinforcing particles increases the composite hardness, Young’s modulus and resistance to frictional wear. However, higher addition of TiB2(7 vol%) was observed to yield less satisfactory results, and despite higher hardness and lower density caused a decrease in other properties tested. The produced materials were characterized by a compact and highly differentiated microstructure free from any noticeable cracks and pores.

Effects of in-situ formed TiB whiskers on microstructure and mechanical properties of spark plasma sintered Ti–B4C and Ti–TiB2 composites

Monolithic titanium, Ti–1 wt% B4C, Ti–2.5 wt% TiB2 were spark plasma sintered at 1050 oC for 5 min under 50 MPa. The effect of B4C and TiB2 additions on densification process, microstructural development and mechanical properties of titanium was investigated. The results revealed that relative density of undoped, B4C- and TiB2-doped Ti samples reached ~98-99%. X-ray diffraction patterns, thermodynamic assessments, and microstructural investigations verified the in-situ formation of TiB whiskers in both composite samples as well as appearance of TiC spheres in Ti–B4C composite. However, trace unreacted TiB2 and B4C additives were remained in the composites as a result of incomplete chemical reactions due to short-time SPS process. Compared to undoped Ti sample, grain growth was hindered when the sample was doped by B4C or TiB2. Elongation, ultimate tensile strength and Vickers hardness of B4C- or TiB2-doped samples were higher than those of monolithic titanium but bending strength of ceramic-doped samples significantly lower, compared to undoped titanium. These outcomes were discussed in detail and related to presence/formation of several ceramic phases with different morphologies in Ti matrix.

Microstructure and mechanical properties of Ti (C, N) based cermets reinforced with different ceramic particles processed by spark plasma sintering

Abstract The addition effect of different ceramic particles such as TiB2, TiN and nano-Si3N4 on the microstructure and mechanical properties of TiCN-WC-Co-Cr3C2 based cermets, which are prepared by spark plasma sintering, was studied. Microstructural characterization of the cermets was done by scanning electron microscope. X-ray diffraction was performed to study the crystal structures. Mechanical properties such as hardness and fracture toughness were measured for the different developed cermets. The hardness and fracture toughness of the TiCN-WC-Co-Cr3C2 cermets without TiN, TiB2, and nano-Si3N4 were 8.4 GPa and 3.4 MPa m1/2, respectively. It was found that 5 wt% TiB2 addition alone improved the corresponding hardness and fracture toughness to 19.2 GPa and 6.9 MPa m1/2, respectively. The addition of 5 wt% TiN, improved the hardness and fracture toughness to 16.7 GPa and 6.9 MPa m1/2, respectively. With the combination of 5 wt% TiN and 5 wt% TiB2, the hardness and fracture toughness were improved to 15.5 GPa and 6.6 MPa m1/2, respectively. But, the addition of 5 wt% Si3N4 showed a balanced improvement in both hardness (17.6 GPa) and toughness (6.9 MPa m1/2). Fracture toughness did not change much for all the above cermets with different ceramic inclusions.

Effect of TiB2 and ZrB2 additions on structure and properties of Fe-7Al based light weight steel

Microstructural modifications and their effect on tensile properties in an Fe-7 wt.% Al alloy by additions of 0.5% TiB2, 0.5% ZrB2 or both has been studied. Alloys are examined in the as-cast as well as in the hot-rolled and annealed conditions. Solidification structure of the Vacuum Arc Remelted pancake ingots was columnar dendritic. Further, boride modified alloys are found to have finer grains in as-cast as well as in hot-rolled and annealed conditions. In the annealed condition, boride containing alloys were found to have superior tensile yield strength, ductility and strain hardening behaviour. These property improvements are attributed to boride aided grain refinement during casting as well as during thermo-mechanical processing of the steels.

Analisis Sifat Fisik dan Mekanik Poros Berulir (Screw) Untuk Pengupas Kulit Ari Kedelai Berbahan Dasar Aluminium Bekas dan Piston Bekas

Aluminum alloys in this study using a mixture of aluminum profiles and former piston. Former piston is used to get the high enough of element Si. The addition of TiB element (Titanium-Boron) as much as 0.02% at the time of casting expected to improve the mechanical and physical character of aluminum, so that expected the aluminum alloy has a strength that is much better than without the addition of any element. Aluminum alloy to manufacture screw will be casted by using sand molds on three types of variations mold temperature 200oC, 300oC and 400oC. The Test were conducted to determine the mechanical properties of the aluminum alloy and physical that are : tensile test, hardness test, and metallographic with an optical microscope. The maximum test result occurred in Al-Si alloy material with TiB addition 0.02% and a heating temperature mold 400oC produces maximum tensile stress of 628.86 N / mm², while for Vickers Hardness Number (VHN) gives the figure of 114 kg / mm2; and for the results obtained from the data metallographic structure formed hypereutectic silicon which form the primary silicon phase. That phase provides high wear resistance. Finally, it is evident that the Al-Si alloys mentioned above can improve the properties of aluminum to manufacture a screw.

The Effect of Charge Component Composition on the Structure and Properties of Titanium Matrix Sintered Composites with High-Modulus Compounds

The effect of the powder matrix base (Ti and TiH2) and the type of reinforcing additives (5 wt.% TiC, TiB2, B, and B4C) on the structurization features and some properties of metallic matrix composites sintered hereof is investigated. It is shown that the application of titanium hydride powder with TiC and TiB2 additives as the starting powder base allows obtaining sintered materials with lower porosity (≤2%) and higher hardness, compared to the composites produced based on commercial titanium powder. The microstructure of sintered composites considerably depends on the type of reinforcing additives. TiC particles hardly interact with the matrix phase and they are relatively equilibrium, while the TiB inclusions (as it is in the case of TiB2 additive) are acicular 1–5 μm in dia. and 10–25 μm long. The microstructure of the composites sintered from the mixture of titanium hydride and boron carbide powders has conglomerates 20–50 μm in size, consisting of highly dispersed acicular particles of titanium boride phases and unimportant number of TiC equilibrium particles.

Measurement of Particles in Molten Al–Si Alloys Applying the Ultrasonic Technique

The present study was undertaken to investigate the capacity of the ultrasonic technique for measuring various particles in liquid aluminum and commercial 356 alloy at two different temperatures each. Particles of TiB2, AlSr, Al3Ti, and Al2O3 were studied using a Metalvision MV20/20 ultrasonic machine. The data provided plots of (1) the cleanliness value, (2) average particle size, and (3) particle count for each particle size range, as a function of testing time. An examination of the microstructure of solidified samples obtained from samplings of the melt was also carried out using Jeol JXA-8900L electron probe microanalyzer. Other techniques, including the liquid metal cleanliness analyzer and all the filtration techniques, can only detect TiB2 particulates when the concentration is very low (less than 10 ppm B). By applying the ultrasonic technique, measurements may be conducted properly for concentrations as high as 90 ppm B; thus, the ultrasonic technique provides an improved alternative for the measurement of TiB2 particulates in liquid aluminum. This fact is of significance, since particles are invariably present because the addition of TiB2 is essential to the grain-refining processes used for aluminum alloys.

Effect of Nanocrystalline TiB2 Addition on Properties of Copper Powder Reinforced Epoxy Composites

The present investigation aims at understanding the influence of nanocrystalline TiB2 powder on thermal and mechanical properties of Epoxy–Cu microcomposites. The nanocrystalline TiB2 powder has been synthesized by SHS and the particle size is in the range of 60–70 nm as revealed from TEM studies. The Epoxy–Cu microcomposites are casted using hand-layout technique and cured under vacuum at room temperature. The nanocomposites have been prepared by addition of 0.2, 0.4, 0.6, 0.8, and 1.0 vol% TiB2 to Epoxy–4 vol% Cu microcomposite. Ductility has increased by 3–4 times in comparison to neat epoxy, and it has increased by 2–3 times in comparison to microcomposites. The Vickers hardness of composites shows an increasing trend with increasing particulate content. XRD studies show the intensity of amorphous epoxy phase decreasing with increasing filler content. The SEM micrographs show a uniform and dispersed distribution of Cu particles in the epoxy matrix. DSC studies reveal the glass transition temperature, Tg, of the epoxy composites to be higher than the neat epoxy and a decreasing trend is observed with increasing filler content.

Effect of TiB2 content on the characteristics of spark plasma sintered Ti–TiBw composites

Spark plasma sintering (SPS) was employed to fabricate monolithic titanium and in-situ formed TiB whisker (TiBw) reinforced titanium matrix composites (TMCs) by adding different amounts of TiB2 as boron source. The sintering process was completed at 1050°C for 5min under 50MPa. The influences of TiB2 content (0.6–9.6wt. %) on microstructural evolution and mechanical properties of TMCs were investigated. Thermodynamics, XRD analysis and microstructural investigations confirmed the in-situ formation of TiBw in the composite samples. However, some semi-reacted TiB2 phases, surrounded by TiB coronas, were remained in the microstructure due to the unfinished chemical reaction between the components during a short-time sintering process. The results showed that all samples were appropriately densified by SPS process into the almost dense parts with relative density no less than 97.5%. While bending strength decreased and hardness increased with increasing TiB2 content, the sample with 4.8wt. % TiB2 had the maximum tensile strength. Fractographical assessments showed that the addition of TiB2 hindered the grain growth of titanium matrix. With increasing TiB2 content, fracture mode changed from a multiple pattern to a predominantly transgranular and brittle state.

Influence of TiB2 nanoparticles on elevated-temperature properties of Al-Mn-Mg 3004 alloy

Two contents (1.5% and 3%) of TiB2 nanoparticles were introduced in Al-Mn-Mg 3004 alloy to study their effects on the elevated-temperature properties. Results show that TiB2 nanoparticles were mainly distributed at the interdendritic grain boundaries with a size range of 20–80 nm, which is confirmed by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Therefore, the volume fraction of the dispersoid free zones is greatly reduced and the motion of grain boundaries and dislocations is inhibited more effectively at elevated temperature. After peak precipitation heat treatment, the yield strengths in the alloy with 3% TiB2 addition at room temperature and 300 °C were increased by 20% and 13% respectively, while the minimum creep rate at 300 °C was reduced to only 1/5 of the base alloy free of TiB2, exhibiting a considerable improvement of elevated-temperature properties in Al-Mn-Mg alloys.

Hot isostatic pressing of in-situ TiB/Ti-6Al-4V composites with novel reinforcement architecture, enhanced hardness and elevated tribological properties

In this study, titanium borides reinforced Ti-6Al-4V composites have been successfully prepared by hot isostatic pressing (HIPing). The microstructure of the as-fabricated samples was investigated using X-ray diffraction technique, secondary electron microscopy and electron backscatter diffraction and the mechanical properties evaluated through micro-hardness and wear resistance measurements together with nano-indentation. It was found that during HIPing the additive particles TiB2 have transformed into TiB needles which tend to decorate at prior particle boundaries of the consolidated powder particles to form a network structure. Under the same HIPing condition, the needles became increasingly coarser and agglomerated with increased addition of TiB2. The micro-hardness of the synthesized materials increased with increased volume fraction of TiB. Nano-indentation measurement demonstrates that the TiB network structure shows much higher nanohardness than the surrounding matrix regions. The friction coefficient of the synthesized composites decreased continuously with increased volume fraction of TiB, indicating improved wear resistance. High resolution transmission electron microscopy analysis on wear debris revealed the formation of a series of oxides suggesting that chemical reaction between alloy elements and oxygen in air may have happened. It is thus believed that the wearing of the current samples is a result of both friction and chemical reaction.

Microstructural characterisation and mechanical properties of spark plasma-sintered TiB2-reinforced titanium matrix composite

ABSTRACTTitanium and titanium matrix composites, reinforced with TiB2 particles, have been synthesised by the spark plasma sintering method at 1050°C under 50 MPa pressure, using mixtures of 2.4 wt.-% TiB2 and 97.6 wt.-% Ti powders. The changes in microstructural features and mechanical properties were investigated. XRD results and SEM observations confirm the formation of TiB whiskers as a result of the reaction between Ti and TiB2. However, some unreacted TiB2 particles have remained in the composite owing to the incomplete chemical reaction between matrix and additives. The measured mechanical properties demonstrate that the increase in hardness and tensile strength with TiB2 addition is mainly attributed to the generation of TiB whiskers, increase in relative density and decrease in grain size, while the reduction in bending strength is possibly due to the plastic restraint imposed on the matrix by the TiB whiskers and unreacted TiB2 particles.

Effect of TiB<sub>2</sub> on Pressureless Sintering and Hot Pressing of ZrB<sub>2</sub>

Zirconium diboride (ZrB2) is a material of particular interest because of the excellent and unique property combination of high melting point and high electrical and thermal conductivity. In this work, the effect of TiB2 addition on pressureless sintering and hot pressing sintering of ZrB2 was investigated. Four compositions were prepared with 0, 5, 10 and 20 wt% of TiB2. First, ZrB2 and TiB2 powders were milled by planetary mill with SiC spheres at for 4 h and then they were wet mixed. Compacted samples were pressureless sintered at 2150 oC/1h and hot pressed at 1850 °C/30min with 20 MPa, both in Ar atmosphere. The added TiB2 completely dissolved into the structure and formed a solid solution with ZrB2. Addition of TiB2 in ZrB2 ceramic improved densification and hardness for both sintering process, but hot pressed samples exhibited better results.

Effect of potent TiB2 addition levels and impurities on the grain refinement of Al

In the present work, the effect of potent TiB2 particle addition levels and impurities on the grain refinement of two Al compositions was investigated. Results showed that no effective grain refinement was achieved in high purity Al (HP-Al) up to particle density levels as high as 2.5 × 1014/m3. In commercial purity Al (CP-Al) fine grain refined structures were observed with merely a particle density of 0.35 × 1013/m3. As more particles were added into the CP-Al melt, the number of grains formed showed an overall increase while the calculated particle efficiency showed a general decrease, consistent with the prediction of interdependence theory. Such results show that the impurities in CP-Al play a significant role in refining the grain structures.