Addition Of TiB2 Research Articles

Improving fracture toughness of B4C – SiC composites by TiB2 addition

B4C-SiC composites can be used in many areas due to their superior properties. However, in order to be used as a body armor material in areas requiring high performance, their fracture toughness needs a degree of improvement. In this study, 0–20 wt% TiB2 was added to B4C-SiC samples that were consolidated at 1950 °C by spark plasma sintering method. The contribution of TiB2 to the microstructure, elastic and mechanical properties of B4C-SiC composites were investigated. The highest hardness was measured to be 29.5 GPa with 15 wt%TiB2 addition. The highest fracture toughness was 3.08 MPa.m1/2 found at sample made with 10 wt% TiB2. Addition of 10 wt% TiB2 increased the fracture toughness by 28%, with only a 5% decrease in relative density. In addition, the fracture mode of B4C-SiC-TiB2 composites is intergranular due to the addition of TiB2.

Surface roughness and microstructure analysis on drilling of titanium diboride in-situ aluminium metal matrix composite

Aluminium and its alloys are widely used for fabricating components are used in aircraft, automobile, defence and structural applications. Due to its light weight and high strength, it is applied in the various commercial purposes such as window, doors, construction member etc. However, machining of aluminium alloys using conventional machining methods is difficult. In this present investigation, an endeavour has been made to drill TiB2 in situ aluminium metal matrix composite alloy developed using stir casting method. During the casting two different salts namely K2TiF6 and KBF4 are added with matrix materials to form TiB2. The paper is studied the surface roughness (SR) of drilled TiB2 in situ aluminium metal matrix composite viz speed, feed rate and TiB2 addition. Empirical relationship is developed for SR in order to identify the dominating factors. The percentage contribution of SR is 96.35% that showed the empirical model is adequate. The normal probability plot showed the points of residuals are equally distributed over the straight line. The lack of fit value was 3.65 which is less than the standard point. Therefore, the SR model is satisfactory. SR increased with increasing of speed, feed rate and addition of TiB2. The removal of TiB2 particles causes small pits and voids due to the inclusion of reinforcement. The minimum SR was achieved at lowest speed (1260 rpm), feed rate (0.05 mm rev−1) and TiB2 addition (2%). As speed and feed increased, the surface hardness increased.

Stable Ti3+ in B-TiO2/BN based hybrids for efficient photocatalytic reduction

Herein, we explored a new 2D heterostructure by hybridizing BN and TiB2, especially the photocatalytic activity of composite materials. Based on the key strategy of developing BN hybrid photocatalysts to change the band structure, we studied the influences of TiB2 addition on the structures and photocatalytic performances of Ti3+-B codoped TiO2/BN. The Ti3+ existed in TiBO3 enables excellent photocatalytic performances in hydrogen production and nitrogen fixation compared with pure BN. We also carried out first-principle calculations using the VASP program to explain the excellent photocatalytic hydrogen production performances. Finally, the photocatalytic mechanism of such TiO2/BN hybrid photocatalysts was proposed.

Effect of Mg and TiB on the Mechanical Properties of A356 Aluminium Alloy Base Materials With Die Casting Process

The development of research on aluminum base materials is very rapid at this time. Aluminum base material reinforced with Mg and TiB particles by the die casting method is the simplest way. The purpose of this study was to see the effect of wt.% Mg and the addition of TiB on the mechanical properties of Al356MgTiB alloy. AlSi was used as a matrix reinforced by Mg with a percentage variation of (3, 4, 5 wt%) and TiB 2 wt%. The method used is die casting. In the casting process, the material is melted down to a liquid state at a temperature of 800 oC. After that the temperature was lowered to a stirring temperature of 640 oC. Then heated again to a pouring temperature of 760 oC. The density value obtained increased with the addition of Mg variation, namely the variation of Mg 4%wt 2.69 g/cm3. The porosity value obtained decreased, namely the variation of the 5%wt Mg element, namely 5.19%. The hardness value of Al356MgTiB alloy increases with the addition of Mg. The highest hardness is achieved at the percentage of Mg 5%wt, which is 65.41 HRB or an increase of 33% from the hardness of the base material. The value of tensile strength increases with the addition of Mg. The highest tensile strength is found in the 4%wt Mg variation, which is 198.4 MPa. The %EL value decreased with the addition of Mg and TiB. The decrease in %EL is accompanied by an increase in the strength of the material. The research was conducted by testing density, hardness testing, and tensile testing.

Effect of temperature on the structure and mechanical properties of SiC–TiB2 composite ceramics by solid-phase spark plasma sintering

SiC composite ceramics have good mechanical properties. In this study, the effect of temperature on the microstructure and mechanical properties of SiC–TiB2 composite ceramics by solid-phase spark plasma sintering (SPS) was investigated. SiC–TiB2 composite ceramics were prepared by SPS method with graphite powder as sintering additive and kept at 1700 °C, 1750 °C, 1800 °C and 50 MPa for 10min.The experimental results show that the proper TiB2 addition can obviously increase the mechanical properties of SiC–TiB2 composite ceramics. Higher sintering temperature results in the aggregation and growth of second-phase TiB2 grains, which decreases the mechanical properties of SiC–TiB2 composite ceramics. Good mechanical properties were obtained at 1750 °C, with a density of 97.3%, Vickers hardness of 26.68 GPa, bending strength of 380 MPa and fracture toughness of 5.16 MPa m1/2.

Understanding the grain refinement mechanisms in aluminium 2319 alloy produced by wire arc additive manufacturing

Controlling the grain size and morphology during fusion-based additive manufacturing remains a challenge for many alloys. This work investigates Titanium diboride (TiB2) nucleant particle addition to the high strength Aluminium 2319 alloy produced during wire arc additive manufacturing (WAAM). Two Cold Metal Transfer (CMT) processing conditions are explored (low heat input CMT and high heat input CMT) and the effectiveness of the grain refiner is studied. The addition of TiB2 is found to refine the average equiaxed grain size by up to 22% compared to the non-inoculated alloy. The Interdependence Model is applied to understand the grain refinement mechanisms occurring in low heat input AM technologies in alloys containing powerful growth restricting solutes such as Al 2319.

Microstructure and mechanical properties of pitch based mixture modified by additions of graphene oxide precursor and TiB2 particles

Pitch based mixture as binder material is crucial component for structure stability and mechanical properties of carbon/graphite electrodes. In this work, coal tar pitch (CTP) mixture was modified by additions of graphene oxide (GO) precursor and fine TiB2 particles. It is found that 1 wt.%GO addition increases the crystallite size, La value and reduce the defects density of (002) planes in CTP mesophase and carbonization products with increased elastic modulus. The additions of 3 or 5 wt.%TiB2 increase the stacking height of (002) planes (Lc) of CTP pyrolysis and carbonization products with increased edge dislocation density and ultimate strain. The combined additions of TiB2 and GO generate a synergistic effect on further improving the mechanical properties of CTP carbonization products with increasing the stacking order of (002) plane, crystallite size (La and Lc) and edge dislocation density. CTP-1GO-5TiB2 shows a compressive strength 194.7 MPa higher than the pure CTP (155.4 MPa). Further findings suggest that a combined mechanism of GO and TiB2 additions can be established through stabilizing C–C bonds while reducing C-O bonds along with chemical component transformations after pyrolysis and carbonization. TiB2 particles play a key role in making the synergistic effect on improving the mechanical strength and reducing the oxidation of C–C bonds with additional increase in La value.

Effect of TiC and TiB2 Additions on the Structure and Properties of Chromium-Containing Composite Coatings

Effect of TiC and TiB2 Additions on the Structure and Properties of Chromium-Containing Composite Coatings

Influence of titanium diboride and graphite on microstructure characteristics and mechanical behaviors of aluminium hybrid nanocomposites

The present work investigates the influence of graphite (Gr) on microstructure and mechanical behaviour of Al7075/TiB2/2wt%Gr hybrid nanocomposite. Aluminium matrix hybrid nanocomposites (AMNCs) were fabricated using electromagnetic stir casting technique. The hybrid nanocomposites were characterized by optical Microstructure (OM), X-ray Diffraction (XRD), Energy Dispersive X-ray Spectrum (EDAS) and Scanning Electron Microscope (SEM). The Al7075/TiB2/Gr hybrid nanocomposties was prepared with 2 wt% Gr nanoparticles addition and 2.5, 5, 7.5, 10 and 12.5 wt% of TiB2 nanoparticles. Results revealed that with the addition of reinforcement hardness of nanocomposties were increased by 145.42BHN to 173.48BHN. Significant improvements in tensile strength, compression strength and flexural strength of AMNCs were attained upto10 wt% TiB2 addition, further decrease in strength at 12.5 wt% TiB2 addition in Al7075 and Al7075 alloy. Considerable enhancement in mechanical properties shows homogenous distribution and agglomerated along the grain boundaries decreases the mechanical properties of the reinforced nanoparticles in the matrix.

In Situ Ti6Al4V/TiB Composites Prepared by Hydrogen-Assisted Sintering of Blends Containing TiH2 and Ball-Milled Ti+TiB2 Powders.

In the present study, 98.6–99.5% dense in situ reinforced Ti6Al4V/TiB composites were manufactured with a newly developed approach based on hydrogen-assisted blended elemental powder metallurgy (BEPM). The approach includes the activation milling of titanium powder produced with hydrogenation-dehydrogenation (HDH-Ti powder) with finer TiB2 additives, following blending with TiH2 and master alloy (MA) powders, and final press-and-sinter operations. Scanning electron microscope (SEM) observations prove the formation of microstructures with improved density and homogeneous distribution of TiB reinforcements in a sintered Ti6Al4V matrix. Hardness and compressive tests validated the high mechanical characteristics of produced composites. The effect of preliminary milling time over 2–6 h and the ratio of hydrogenated and non-hydrogenated titanium powders used (TiH2 vs. HDH Ti) on microstructure and mechanical properties were studied to further optimize the processing parameters. Test results indicate the above approach can be regarded as a promising route for the cost-effective manufacturing of Ti6Al4V/TiB composite with reduced porosity, tailored microstructure uniformity, acceptable impurity level and, hence, mechanical characteristics sufficient for practice applications.

Mechanical properties of casting titanium alloy matrix composites reinforced by WC and TiB2 ceramic particulates

Casting Titanium alloys with Wc and TiB2 additives have their mechanical characteristics examined in this work. The mechanical properties of aged titanium alloys are very impressive. UTS reach 406 MPa and YS of 253 MPa and an El of 7.4 percent. Pinned primary Wc and TiB2 phases reduced fineness by more than half, while enhancing assorted nucleation on Wc and TiB2 initial phases boosted nucleation and growth resistance. Following the heat treatment, foundational designed with the intent emerged from the substrate. There are no more stages in the shell. Those alloys containing Wc, on the other hand, have cores composed of Wc and TiB2. From 0.1 wt% to 0.2 wt% of Wc and TiB2 content, core radius rises, but shell width does not appear to change, and particle density does not appear to be altered. In time, composite particles became coarser, but their core dimensions stayed nearly same. As predicted, the exponent (n-1) is less than the expected value of 0.33, Perhaps this is because of the low temperature, which prevents a developed a semi state from emerging. The kinetics are consistent with the KV model's predictions.

STUDY ON THE DENSIFICATION OF ALN-TIB2 COMPOSITES BY HOT PRESSED SINTERING

The AlN-TiB2 composites were prepared by hot pressing sintering process and the effects of TiB2 content and sintering process on the densification of AlN-TiB2 composites were studied. The results showed that at 1900℃ for 1h, the relative density reached more than 98.6% and the TiB2 content had no effect on densification of the composites. The phase composition and microstructure of the composites were also studied. Two-phase BN and TiN are newly formed in the sintering process of AlN-TiB2 multiphase material, so the multiphase material is composed of four phases, the primary crystal phase is AlN and TiB2, and the secondary crystal phase is BN and TiN. With the increase of sintering temperature and the extension of holding time, the density of AlN-TiB2 multiphase materials gradually increases. The optimum sintering temperature and holding time were 1900℃ and 1h respectively. The addition of TiB2 does not affect the sintering of multiphase materials.The multiphase materials have achieved high density.

Effect of spark plasma sintering and reinforcements on the formation of ultra-fine and nanograins in AA2024-TiB2-Y hybrid composites

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-TiB2-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of TiB2, the hard and brittle Al3Ti phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 ​wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 ​wt% promoted the formation of bi-modal size grains (ultra-fine and nano) along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to Joule's heating and thermo-mechanical fatigue. Among all the sintered composites, the highest hardness (137 HV), ultimate tensile strength (UTS) (496 ​MPa), yield strength (YS) (438 ​MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 ​wt% TiB2 and 0.3 ​wt% yttrium.

Microstructure and mechanical properties of a novel (TiB2+TiC)/AlSi10Mg composite prepared by selective laser melting

The (TiB2+TiC)/AlSi10Mg composite powders with 1.5 wt% nano-TiB2 particles and 1.5 wt% nano-TiC particles were prepared by ball milling. Aluminum matrix composites (AMCs) reinforced by TiB2 and TiC were fabricated via SLM with optimal processing parameters. The (TiB2+TiC)/AlSi10Mg composites showed a very high ultimate tensile strength ∼552.4 MP and excellent ductility ∼12%, which is 40.3% and 166.7% higher than that of unreinforced AlSi10Mg, respectively. The effects of TiB2 and TiC nanoparticles on the SLM processability, microstructures, grain size, and crystallographic texture of (TiB2+TiC)/AlSi10Mg composite were systematically investigated to uncover its underlying strengthening mechanisms. The results showed that the addition of 1.5 wt% nano-TiB2 and nano-TiC particles can obtain fine-equiaxed grains, facilitate microstructural homogeneity, and consequently improved mechanical properties of AlSi10Mg alloy. With the addition of TiB2 and TiC nanoparticles, the coarse columnar grains are completely transformed into equiaxed grains and the average grain size decreases from 12.1 μm to 1.5 μm.

Effect of stress and temperature on creep behavior of a (TiB + TiC + Y2O3)/α-Ti composite

A (TiB + TiC + Y2O3)/α-Ti composite was prepared by induction skull melting to investigate the microstructure evolution, high temperature tensile properties and the creep behavior. The results show that the original microstructure of the composite is a basket-weave structure with a little equiaxed α phase. The UTS of the composite is 710 MPa at 650 °C and 581 MPa at 700 °C. Stress exponents of the composite are found to 4.5 at 650 °C and 3.9 at 700 °C, respectively, showing the dislocation climbing is the dominant mechanism of the creep process at both temperatures. Reinforcements including TiB, TiC and Y2O3 can effectively impede the movement of dislocations, which contributes to the improvement of creep properties. The formation of equiaxed α phase is promoted by the addition of TiB and can decrease the creep resistance to some extent. Microstructure instabilities occur during creep process, especially the precipitation of silicides, which is strongly associated with the temperature and the stress. At 650 °C, the composite has S2-type silicide with ellipsoid morphology and (Ti, Zr)x(Sn, Si)y type silicide with equiaxed morphology. At 700 °C, the composite has S1-type silicide with rod morphology. The increase of the stress will promote the growth and rearrangement of the silicides. The precipitation of silicides can be observed in the crystal defects region near the TiB and Y2O3 reinforcements. These silicides have strong pinning effect on dislocations and improve the creep resistance.

Phase-field modeling of grain evolution in additive manufacturing with addition of reinforcing particles

Metal matrix composite parts fabricated by additive manufacturing are of interest due to their fine grain structures and superior mechanical properties. In this study, a phase-field (PF) model is developed to simulate the grain evolution of TiB 2 /316L stainless steel composite during the selective laser melting (SLM) process. The reinforcing TiB 2 particles are explicitly incorporated into the PF model, and the influences on grain evolutions are comprehensively considered, including the induced heterogeneous nucleation and the pinning effect on grain boundaries. The simulation results demonstrate that with the addition of TiB 2 particles, both columnar and equiaxed grains are formed in the scanning track. While the columnar grains are due to epitaxial growth from the molten pool boundary, the TiB 2 particles act as the nucleation sites inside the molten pool, resulting in the formation of equiaxed grains. The grain boundaries become complicated due to the pinning of grain boundaries by TiB 2 particles. As the content of TiB 2 particles increases, the grain size decreases and the equiaxed grains are closer to the fusion boundary of the scanning track, which are attributed to the increasing nucleation sites and the retarded grain growth during solidification. In addition, the grain coarsening in previous layers is restrained due to the Zener pinning effect. The simulated grain morphology and the predicted influence trend of the TiB 2 content on grain morphology are in good agreement with the experimental observations in the literature.

Effect of TiB2 on the self-crack-healing ability of SiC-Si coating at 1300 °C

TiB 2 -SiC-Si coating was prepared on the surface of C/C composites by slurry immersion pyrolysis combined with gas-phase silicon infiltration method. The influence of the addition of TiB 2 on the oxidation resistance of Si-SiC coating was studied. TiB 2 significantly increases the oxidation protection time of the SiC-Si coating at 1300 °C. The TiB 2 modified Si-SiC coating displayed a weight increase (0.03%) after oxidation at 1300 °C for 300 h, while the unmodified coating had a weight loss of 0.84% after oxidation at 1300 °C for 100 h. It is found through experiments that doping TiB 2 produces more molten glass phases when the ceramic coating is oxidized at 1300 °C, which effectively heals cracks and plays a good protective performance. • A TiB 2 -SiC-Si coating with self-crack-healing ability was fabricated. • Oxidation and thermal shock resistance of the coating were investigated. • The mass increase of the samples was 0.03% after oxidation at 1300 °C for 300 h. • The weight loss of the TiB 2 -SiC-Si coating is 0.82% after 30 thermal cycles. • TiB 2 can promote the healing of cracks in the coating.

Enhanced Antiwear Property of Cu-Sn-Bi Bimetal Composites with TiB2 under Different Working Conditions

The present study investigated the effect of TiB2 on the tribological properties of CuSn10Bi3 bimetallic bearing materials. CuSn10Bi3 samples with different contents of TiB2 were fabricated by powder sintering technology. Their metallographic structures and tribological characteristics under different working conditions were analyzed and compared. The results showed that TiB2 refine the copper alloy grains, passivate the grain boundary edges and reduce the surface porosity of the sample. When the content of TiB2 is 1%, the wear rate under different oil conditions (oil-rich, oilless, and dry friction) is reduced by 42%-95%. The sharp decrease in the wear rate is attributed to the enhancement of the micro-grain structure of the copper alloy matrix material by TiB2 hard particles with antiwear properties, and the high hardness and high wear resistance of TiB2. The wear tracks were analyzed through SEM and EDS, and it was concluded that the addition of TiB2 enhanced the wear resistance.

Microstructures, mechanical properties, and aging behavior of hybrid-sized TiB2 particulate-reinforced 2219 aluminum matrix composites

Particulate-reinforced aluminum matrix composites are widely used owing to their advantageous comprehensive performance. For these composites, aging treatment is an important and essential process. However, researchers have discrepant opinions regarding the exact effects of particles on the aging behavior. In this study, the aging behavior of TiB2/2219Al composites is analyzed in terms of thermodynamics and kinetics. The results reveal that the particles can both promote aging and impede aging, and the peak aging times of the composites are advanced in this study. The effects of hybrid-sized TiB2 particles on the microstructures and mechanical properties of aged TiB2/2219Al composites are investigated. The results show noticeable dislocation propagation after the addition of TiB2, and this is confirmed by transmission electron microscopy observations and modified Williamson–Hall equation calculations. The Vickers hardness values are increased under all aging conditions. The strengths of the naturally aged composite, yield strength of the under-aged composite, and Young's modulus are increased significantly, whereas the strengths of composites under other aging conditions record only slight improvement. The total elongations of all the composites are decreased owing to the presence of TiB2 agglomerates.

Microstructure Refinement and Strengthening–Toughening Mechanisms of Gray Cast Irons Reinforced by In Situ Nanosized TiB2–TiC/Al Master Alloy

Herein, the effects of addition of TiB2–TiC nanoparticles on the microstructure and tensile properties of as‐cast gray cast irons are investigated. The in situ nanosized TiB2–TiC/Al master alloy is added in the casting process. It is found that the presence of TiB2–TiC nanoparticles refines the graphite flakes and pearlite and increases the yield strength, tensile strength, and fracture strain simultaneously. The strengthening mechanisms are related to grain refining strengthening and Orowan strengthening. The toughening mechanism is related to the scattering behavior of cracks by nanoparticles.