The consolidation of the Al203/TiB2 into a dense and high-strength body is difficult because of the high degree of covalent bonding and low self-diffusion coefficient of the constituent elements. Synthesis of fine and homogenous structure in which one phase homogenously dispersed in the other can resolve this problem. Consolidation of Al203/TiB2 nano-composite powder derived from two different synthesis methods was investigated. Also the effect of processing condition on the sintering behavior, microstructure, and hardness of the densified samples were evaluated. In the first synthesis method a composite structure containing of an Al203 matrix with dispersed TiB2 particles was obtained via mechanical alloying of AI, Ti02 and B203 powder mixture. In the second method Al203/TiB2 nano­ composite powder was prepared from TTIP (TITANIUM tetra iso propoxide) and B203 using a sol-gel method followed by mechano-chemical reduction in the presence of AI. For sample which prepared by milling assisted sol-gel method, vickers hardness value of hot pressed sample at 1500oC was measured as 15.3 GPa and indentation fracture toughness was calculated as 10.1 MPa.m1/2; while for mechano-chemically synthesized sample this parameters are 20 GPa and 11.4 MPa.m1/2 respectively. Analysis of the diffraction pattern of samples revealed the presence of Al203, TiB2, and Al18B4O33 in the samples. Several factors favors the sintering process of the Al203-TiB2 nano-composite particles at low temperature and short time which include; (1) the nanostructured Al203-TiB2 particles, (2) the disordered crystal structure of the powder and (3) liquid phase formation of Al18B4O33.

Titnium DIBORIDE is a wear-resistant compound having high hardness, low density and high electrical and thermal conductivity in the solid state. In this study, the explosive powder metallurgy process for production of samples from TiB2 powder was investigated. At first, analytical solution of the explosive powder metallurgy process with water as interface medium was performed in order to determine the suitable explosive material to consolidate the TiB2 powder. In the experimental section, with the different design of assemblies the pieces were produced with this method. Analysis of the density and hardness of the produced parts showed that the use of momentum traps with proper height and TITANIUM powder in the assemblies, can reduce the shock wave stretching back into the die and produce disks with relative density of 98% and a hardness of 2600 Vickers. In addition, investigation of the microstructure of the produced components using scanning electron microscopy showed that there was a good connection between the powder particles and the samples were free of any cracks.

In this research, 3 layer composite weld containing TITANIUM DIBORIDE (TiB2) on low carbon steel (ST37) was carried out through flux cored arc welding via flux cored electrodes containing 100% TiB2 and 50-50 TiB2-Fe. Then, wear and microhardness tests were used for surviving hardness and wear behavior of samples. The obtained results showed that by increasing volume percent of TiB2 in microstructure, the hardness of layers increased. Also, the highest wear resistance belonged to third layer of sample with 50% TiB2 and thereafter, belonged to first layer of sample with 100% TiB2. The scanning electron microscopic investigation of samples wear surfaces indicated that by increasing volume fraction of TiB2 into layers, the depth wear scratches in the third and second layers decreased and segregation of wear debris in these layers increased, compared with first layer. Also, it was found that by increasing the layers, wear mechanism changed from ploughing to cutting.

High-temperature ceramics possess significant potential for aerospace, military, and industrial applications due to their unique properties. One such ceramic is the ZrB2-SiC composite, which has garnered considerable attention and extensive research. This study investigated the effect of adding TiB2 on the pressureless sintering behavior, as well as the mechanical, microstructural, and thermal properties of the ZrB2-SiC nanocomposite. For this purpose, TiB2 particles were added in varying amounts of 0, 5, 10, 15, 20, 25, and 30 weight percent, with a constant amount of 3 weight percent B4C, to the ZrB2-15.5 vol.% SiC nano/micron matrix. The resulting powders were ball-milled for 2 hours at 300 rpm. The resulting mixtures were first uniaxially pressed at 100 MPa and then subjected to cold isostatic pressing (CIP) at 200 MPa. The samples were subsequently sintered at 2100°C in an argon atmosphere using the pressureless sintering method. The results indicated that the formation of the solid solution (Zr,Ti)B2 in the compositions led to improvements in the physical and mechanical properties of the samples. The highest properties were observed in the sample containing 30 weight percent TiB2, with a relative density of 96.66%, hardness of 16.74 GPa, and fracture toughness of 4.69 MPa.m1/2. The results also showed that the addition of TiB2 did not improve the oxidation resistance of the samples, with the highest oxidation resistance observed in the sample without TiB2, which had a mass erosion rate of 1.37 mg/s and a linear erosion rate of 1.03 mm/s.

sintering of Al2O3- TiB2 nanocomposite Synthesized via Mechanochemical synthesis method were studied In order to improveits properties. For this purpose, First The raw materials include Al powder, TiO2 and B2O3 mixed with stoichiometric ratio were milled at room temperature under inert atmosphere at 2.5, 6 and 10h periods. In order to determine the phases formed and Crystalline grain size, X-ray diffraction analysis was used. To investigate the sintering behavior of Prepared powders were pressed at a pressure 700MP and green porosity and density was measured. Samples were sintered inside the furnace under inert at temperatures from 1100 to 1400oc for 1 to 4 hours. Finally, inorder to optimize the sintering temperature and time, The final properties in eluding compressive strength, hardness, density were studied. To study the morphology and particle size, Scanning Electron Microscope (SEM) were used. The results showed that the complete sintering is carried out at a temperature of 1400oc. At this temperature, The sample had high estdensity (3.8 gr/cm3) and alsohas a hardness 927HV and the compressive streng this 500 Mpa.

TiB2 powder was synthesized via simultaneous Aluminum reduction of TiO2 and B2O3 according to SHS reaction in an oxidation atmosphere. This method opposite to other methods, does not need to have controlled atmosphere and high temperature. In this work, Taguchi experimental design was used and different effective parameters and their ranges were studied. Then, the related levels of experiments were determined for Taguchi method and various experiments were carried out based on the determined variation levels. Using statistical calculations, contribution percentage of each parameter was calculated and the most suitable conditions were extracted. Finally, the accuracy experiments were carried out so that the results were corresponded on what obtained from calculations. ‏The most appropriate conditions of synthesis consists of: 1170°C, 0.5 hr, Al and B2O3 powder contents 1.194 and 1.124 in stoichiometric ratio, respectively, particle size less than 44 mm for Al powder and between the range of 63 mm to 149 mm for TiO2 and B2O3 powders.

The influence of mechanical activation by ball milling (BM) of Ti, B and graphite powders mixture on the synthesis of B4C-TiB2 (1: 1 mole ratio) composite by Spark Plasma Sintering (SPS) is investigated. The milled powders at 0, 3 and 8 h were chosen for investigation of synthesis mechanism, density and microstructure of powder and dense products. Results showed the milling influence on temperature and time of reactants conversion to products, but it does not have any effect on mechanism of synthesis. The synthesis process occurs through a solid-state diffusion mechanism where the first crystalline phase formed is TiB, which is gradually converted to TiB2, while the formation of B4C takes place subsequently. Investigation showed that with using 8 h milled reactant; nanostructure composite powder could be obtained. As a consequence of the mechanical treatment up to 8h, SPS product density increases from about 82% to 94% of the theoretical value. Correspondingly, a material with homogeneous phase distribution and grain submicron size is obtained.

In this study, in situ synthesis of B4C-TiB2 nanocomposite powder was performed by mechanically activated combustion synthesis method. The molar ratio of B2O3: TiO2: Mg: C was 3: 1: 12: 1 to obtain the B4C-TiB2 nanocomposite. The milling process was used to mechanically activate the raw materials. Synthesis of prepared samples occurred in a furnace under argon atmosphere at 900 ºC. The milling parameters were examined to optimize the activating process of the raw materials. The specimens were studied in various steps by XRD analysis for evaluation of phase compositions. Initially, the synthesized samples contained MgO, B4C, TiB2 and a small amount of magnesium borates. XRD analysis after acid leaching of the combustion products showed a great effect of acid leaching on removing the impurities. It was demonstrated that mechanical activation is a useful method for simultaneous obtaining of B4C and TiB2 powders. Morphology of the synthesized products was investigated by scanning and transmission electron microscopies (SEM & TEM). The final products were synthesized with a homogeneous morphology. The SEM analysis showed that the sample with 12 h of milling is made up of more uniform grains with smaller particle sizes (˂ 100 nm) than the sample with 6 h of milling.

This study investigated the effect of adding boron carbide microparticles (B4C) and TITANIUM DIBORIDE nanoparticles (TiB2) on the microstructure, tensile strength, and hardness of A356 aluminum composite. In so doing, 2.5, 5, and 7.5 vol.% B4C reinforcements and 2.5 vol.% TiB2 reinforcement were added to the field by stir casting at 1000 °C using in situ process. The TiB2 nanoparticles were processed in situ by cryolite precursors (Na3AlF6), TITANIUM oxide (TiO2), and potassium tetrafluoroborate (KBF4) in aluminum melt, and B4C microparticles were added directly into the melt. X-ray diffraction (XRD), optical microscope (OM), and scanning electron microscope (SEM) were used to investigate the microstructure and failure mechanism of the samples. Also, hardness and tensile tests were carried out to test mechanical properties. The results showed that addition of B4C first decreased and then increased the ultimate tensile strength compared to the sample without reinforcement. Moreover, the highest value of tensile strength was for the sample containing 2.5 vol.% of B4C and 2.5 vol.% TiB2, which showed a 235% improvement compared to the sample without an amplifier. However, the tensile strength of the sample containing 2.5 vol.% of B4C was reduced by 35% compared to the sample without reinforcement. The results of the hardness test showed a drop in properties of the samples containing 2.5% of B4C reinforcement. the highest value of tensile strength was for the sample containing 2.5 vol.% of B4C and 2.5 vol.% TiB2, which showed a 33% improvement compared to the sample without reinforcement.