Solid Solution Of Titanium Research Articles

Configuration Effect of Plasmonic Vanadium–Titanium Solid Solutions for Photo-oxidation of Benzyl Alcohol

Configuration Effect of Plasmonic Vanadium–Titanium Solid Solutions for Photo-oxidation of Benzyl Alcohol

Hydrogen adsorption by a porous bimetallic solid solution carbide MAX phases synthesized in an open atmosphere

Multilayer and porosity are significant traits for energy storage materials, especially for hydrogen storage and utilization. However, the material must first undergo subsequent sequential investigation for accurate quantification to be a candidate for hydrogen storage. The mixed metallic MAX phase and their derivatives MXene have the potential to be used for hydrogen storage. In this paper, we describe the formation of low temperature (1100 °C), porous, and high purity (84.92 %) bimetallic solid solution Titanium Vanadium Aluminum Carbide (TiVAlxC) MAX phases in an open atmosphere, where the variation of x, e.g., Al mole content, is critical for obtaining high purity metallic solid solution MAX phases. The BET comparative analysis shows the textural features of the TiVAlxC with change in Al and end phases, i.e., Ti2AlC (Titanium Aluminum Carbide) and (Vanadium Aluminum Carbide) V2AlC. The outcomes are evident that impurity, crystallinity, and crystallite size impact the textural properties of the synthesized MAX phases. Corelative findings on accurate quantification of hydrogen uptake based upon textural properties. The gravimetric hydrogen storage capacity of Ti2AlC, TiVAl1.3C, and V2AlC phases are 0.33, 0.62, and 1.29%wt, respectively. The gravimetric analysis provided valuable insights into the isothermal hydrogen adsorption of TiVAlxC and its end phases, demonstrating these materials' ability to be used for future hydrogen storage.

Formation mechanism of titanium solid solution and its influence on equiaxed behavior of α phase of Ti–5Al–5Mo–5Cr–2Zr-xNb alloys

To clarify the formation mechanism of titanium solid solution (Tiss) and its effect on the microstructure, Ti–5Al–5Mo–5Cr–2Zr-xNb alloys are prepared by vacuum induction melting and multi-directional forging (MDF). The results show that the alloy phase is composed of grain boundary α (αGB), primary α (αp), secondary α (αs) and residual β phases. The crystal structure of Tiss is consistent with that of the β phase. Nb atoms rapidly spread along the dislocations and aggregated to the α phase boundary during MDF, and Nb atoms dissolved in the lattice of the β phase to form Tiss. There are (0002)α∥(3¯21¯)Tiss and (011¯0)α∥(121¯)Tiss orientation between titanium solid solution and equiaxed αp phase. Therefore, the equiaxed behavior of the αp phase is characterized by the formation of new phase boundaries caused by dislocations captured by Tiss. The tensile strength and toughness increased when the Nb content increased from 3 to 9%, which is attributed to the increase in the α phase content and the solid solution strengthening of Nb. When the Nb content increased to 12 wt.%, the tensile strength and toughness decreased due to the debonding of the lamellar αp phase. The equiaxed αp phase improves the plasticity of the titanium alloy, so the strain decreases with decreasing content.

Influence of the Component Ratio in the Ti–B System on the Structure and Properties of Materials Fabricated by SHS Extrusion

We studied how the ratio of precursor titanium and boron powders influenced the combustion temperature and combustion velocity in the high-temperature self-propagating synthesis (SHS) mode, and the microstructure, phase composition, and mechanophysical properties of rods fabricated by SHS extrusion. The subject matters of the study were materials for which the as-batch phase compositions of products were TiB–(20–40) wt % Ti. The formation of boron solid solution in titanium was considered. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and mechanical measurements implied the texture of the prepared materials (TiB whiskers were aligned in the direction in which the external pressure was applied). In all of the composites studied, the conductivity was close to the conductivity of undoped titanium; the electrical resistance increased slightly in response to increasing boron weight fraction. The three-point bending strength of the material increased by a factor of 1.7 at most as the weight fraction of boron solid solution in titanium increased from 20 to 40 wt %.

Microstructural Evolution and Mechanical Properties of Cu/Ti Joints Welded by Ultrasonic Spot-Welding with Zn Interlayer

Cu/Ti dissimilar metals were joined together utilizing ultrasonic spot welding with a Zn interlayer. The threedimensional finite element analysis model was established to simulate the temperature field of the interface of Cu/Ti ultrasonic welding joint under different welding energies. The interface forming, microstructure, and mechanical properties of the Cu/Zn/Ti ultrasonic spot-welded joints were studied systematically. Results showed that the temperature distribution of the interface of the Cu/Zn/Ti ultrasonic welding joint was inhomogeneous, and the temperature of the interface below the indentation reached the highest and decreased gradually to the surrounding. With the increase of welding energy, the maximum temperature and the corresponding high-temperature region of Cu/Zn/Ti joint interface gradually increased. The interface of Cu/Zn/Ti ultrasonic welding joint was well formed, and the thickness was different, and the local position had wavy undulation morphology. When the welding energy was low, the interface microstructure was mainly composed of copper solid solution and titanium solid solution. As the welding energy increased, the microstructure of the joint interface was composed of CuZn compound, copper solid solution and titanium solid solution. When the welding energy was increased to 2000 J, the joint interface microstructure was composed of CuZn, Zn15Ti compound and copper solid solution. In comparison, Cu/Ti joints welded with a Zn interlayer in-between displayed the maximum shearing force about 33.5% greater than those of joints without a Zn interlayer.

Characterization of the Interface Between \u03b1 and \u03b2 Titanium Alloys in the Diffusion Couple

The aim of the research was to investigate the microstructural changes caused by diffusion through interface between α and β titanium solid solutions. For this purpose, a diffusion couple composed of two single-phase titanium alloys—α type commercially pure (CP) titanium Grade 2 and near-β Ti-15V-3Al-3Cr-3Sn—was made by annealing at a temperature of 850 °C in an inert atmosphere. The performed heat treatment caused partial diffusion bonding (DB) where the α/β-interface was clearly visible. Based on the results of microscopic (light microscope (LM), scanning electron microscope/electron backscatter diffraction (SEM/EBSD), and transmission electron microscope (TEM)) examination, a significant microstructure evolution of near-β alloy in the region near the interface (diffusion-affected zone) was revealed. It was found that needlelike phases were formed both in α and β solid solutions. Moreover, in the near-β titanium alloy, pores aligned in the Frenkel plane were found. The latter finding indicated that the diffusion of alloying elements of near-β alloy is the most probable reason for the observed microstructural changes. Additionally, the “grooving” phenomenon at the α/β interface was found and it was correlated with faster diffusion through grain boundaries, rather than volume diffusion. Finally, the pore size was measured and numerically modeled. The calculated values were in good agreement with the experimental ones.

Anode plasma electrolytic borocarburising of alpha + beta-titanium alloy

The structure of alpha + beta-titanium alloy, its microhardness, surface roughness, and wear and corrosion resistance after anode plasma electrolytic borocarburising (PEB/C) in electrolyte containing boric acid, glycerol and ammonium chloride were investigated. An X-ray diffractometer and scanning electron microscopy were used to characterize the phase composition and structure of the modified surface. Tribological properties of treated titanium alloy were evaluated using a ball-on-disc tribometer under dry testing conditions. The effect of electrolyte compositions on corrosion resistance of the PEB/C samples was examined by means of potentiodynamic polarization in Ringer's solution. It was shown that the electrolyte containing boric acid, glycerol and ammonium chloride provided the saturation of alloy with boron, carbon and oxygen and formation of TiO2 with rutile structure and boron/carbon solid solution in titanium. The anode PEB/C resulted in a decrease in surface roughness by 2.5 times, corrosion current density by 9 times, wear rate by 54 times and an increase in microhardness to 1075 HV10.

Increasing wear resistance of Ti6Al4V alloy by anodic saturation with carbon and nitrogen

In this paper, anodic plasma electrolytic nitrocarburising (PEN/C) was applied to Ti6Al4V alloy. This treatment was carried out in electrolyte containing ammonia (5 wt.%), acetone (5 wt.%) and ammonium chloride (10 wt.%) during 5 min at treatment temperature from 750 to 900°C. There were investigated the alloy microhardness, surface roughness and wear resistance. It was shown that the PEN/C results in saturation of studied alloy with oxygen, nitrogen and carbon include formation TiO2 with rutile structure and solid solution in titanium of nitrogen and carbon. This structure provides an increase in microhardness of the surface layer up to 940 HV by sealing the crystal lattice. Surface roughness Ra of treated samples decreases by 1.2–1.4 times and wear resistance increases by 9–10 times after PEN/C. Friction coefficient of PEN/C samples was reduced by 1.5-fold after treatment at 750°C.

Effect of Heating Temperature on the Grain Size and Titanium Solid-Solution of Titanium Microalloyed Steels

Through studying on the heating process of titanium microalloyed steels, the influence of heating temperature on the austenite grain size and the solid dissolution, precipitation law of Ti microalloying element were analyzed, and the results showed that, the austenite grain size increased with the increase of heating temperature, When the heating temperature reached 1050°C and 1250°C, the austenite grains appeared the obvious coarsening process twice. TiC particles dissolved gradually as the heating temperature increased. When the heating temperature rose to 1100°C, TiC particles disappeared basically, When the heating temperature rose to 1250°C, TiN particles began to be dissolved and grow up.

Mechanical properties and microstructure of Ti5Si3 based composites prepared by combination of MASHS and SPS in Ti-Si-Ni and Ti-Si-Ni-C systems

Abstract Mechanical properties, synthesis behavior, microstructure and oxidation resistance of Ti5Si3-based composites prepared by combination of mechanically activated self-propagating high-temperature synthesis (MASHS) and spark plasma sintering (SPS) in Ti-Si-Ni and Ti-Si-Ni-C systems were investigated. Ti5Si3-Ti2Ni composite was synthesized in Ti-Si-Ni system while Ti5Si3-TiC-Ti2Ni was formed in the Ti-Si-Ni-C. Microstructural analyses showed that Ni and C extensively distributed in Ti5Si3 phase and formed interstitial and substitutional solid solution titanium silicide. The activation energy values of 126 and 135 kJ/mol were calculated for initiation of combustion reaction in Ti-Si-Ni and Ti-Si-Ni-C systems, respectively. The isothermal oxidation behavior of the samples in air atmosphere was studied by TGA analysis and near the same oxidation resistance was detected. The fracture toughness of fabricated composites in Ti-Si-Ni and Ti-Si-Ni-C systems reached to 5 ± 0.1 and 6.1 ± 0.12 MPam1/2, respectively. The higher fracture toughness in Ti-Si-Ni-C system is related to the uniform distribution of TiC in the composite.

Hydrogen enhanced thermodynamic properties and kinetics of calciothermic deoxygenation of titanium-oxygen solid solutions

Titanium has a strong chemical affinity to oxygen, which makes it difficult and costly to produce. It is especially challenging to produce pure or ultra-pure metal when extremely low oxygen content is required, because titanium has a high solubility for oxygen, and the solid solution of titanium with oxygen is thermodynamically more stable than titanium oxides. This paper presents a novel method for removing oxygen from Ti metal by using calcium as the reducing agent in hydrogen. Although Ca has been known to be an effective deoxygenation agent for Ti, the effect of hydrogen on deoxygenation of Ti by Ca is still unclear. The effect of hydrogen on calcium deoxygenation of titanium is systematically studied in this work, and the mechanism for removing oxygen has been clarified. Hydrogen not only transforms α TiO to β or to the hydride phase depending on the amount of hydrogen and the reaction temperature, and destabilizes the interstitial oxygen in the titanium lattice, but also transforms calcium to a salt like hydride component. The limit of deoxygenation can be decreased to <10 ppm at 750 °C based on the thermodynamic modeling. In addition, a model of the kinetics was built based on Fick's law of diffusion. The oxygen diffusion coefficients in α TiO and β TiOH at 750 °C were determined to be ∼5 × 10−15 m2/s and ∼5 × 10−13 m2/s, respectively. The results of both experiments and modeling demonstrate the significant differences between the rates of the deoxygenation with and without hydrogen.

Anodic plasma electrolytic nitrocarburising of VT22 titanium alloy in carbamide and ammonium chloride electrolyte

The structure of alpha- and beta-titanium alloy VT22, its microhardness, surface roughness, wear and corrosion resistance after anodic plasma electrolytic nitrocarburising in an electrolyte containing carbamide and ammonium chloride were investigated. An X-ray diffractometer and a scanning electron microscope were used to characterize the phase composition and structure of the modified surface. Tribological properties of the treated titanium alloy were evaluated using a ball-on-disc tribometer under lubricated testing conditions. The effect of processing temperature on corrosion resistance of the plasma electrolytic nitrocarburising samples was examined by means of potentiodynamic polarization in Ringer’s solution. It was shown that the anodic nitrocarburising provides saturation of the titanium alloy with oxygen, nitrogen and carbon and the formation of TiO2 with a rutile structure and a nitrogen/carbon solid solution in titanium. The anodic plasma electrolytic nitrocarburising at all treatment temperatures diminishes the wear rate of the titanium alloy samples and the surface roughness. Friction coefficient of treated samples can be reduced by 4.7 times. The anodic nitrocarburising results in an enhanced corrosion resistance since the corrosion potential increases by an order of magnitude.

Characterization of Thermochemically Surface-Hardened Titanium by Light Optical Microscopy

Abstract Thermochemically treated titanium grades 2 and 5 were investigated by light optical microscopy and hardness indentation. Gaseous oxidation in oxygen and N2O containing atmospheres resulted in a diffusion zone of oxygen in solid solution in titanium with a hardness up to 1000 HV. A surface scale consisting of oxide can be present depending on the treatment conditions. A new type of carbo-oxidation treatment was applied, where carbon and oxygen are simultaneously incorporated into the surface. This resulted in new microstructural features such as a deep zone of mixed interstitial solid solution, i.e., a diffusion zone, and surface regions consisting of a mixed interstitial compound (TiCXO1 − X structure). Carbo-oxidation yields hardness values in excess of 2500 HV in the mixed interstitial compound and values up to 1500 HV in the diffusion zone. Simultaneously, with the surface hardening treatment, core hardening of the material can be obtained.

Plasma electrolytic treatment of VT22 titanium alloy in electrolytes with carbon-containing compounds

The study investigates the influence of electrolyte compositions containing acetone, glycerol, sucrose, ethylene glycol and ammonium chloride on the properties of VT22 titanium alloy in the process of the anode plasma electrolytic treatment (PET). An X-ray diffractometer and a scanning electron microscopy (SEM) were used to characterize the phase composition and morphology of the modified surface. Tribological properties of the treated titanium alloy were evaluated using a pin-on-disc tribometer under lubricated testing conditions. The effect of electrolyte compositions on the corrosion resistance of the PET samples was examined by means of potentiodynamic polarization in a solution of Na2SO4. It was assumed that the PET provides the saturation of titanium alloy with oxygen and carbon and formation TiO2 with a rutile structure and carbon solid solution in titanium. The anode PET in an electrolyte with glycerol results in an increase in microhardness to 540 HV and a decrease in the corrosion current density by 2.4 times. The friction coefficient of the treated samples in anelectrolyte with sucrose can be reduced 7.5 times. The anode PET in all electrolytes enables todiminish the wear rate of the titanium alloy samples by 3 orders of magnitude and the surface roughness, too, due to the anode dissolution of titanium.

The Structure and Phase Composition of the Diffusion Zone in a Titanium and Steel Composite

An investigation is performed on the influence of the temperature and duration of heating of the explosively welded titanium ВТ1-0+ Steel 20 composite on the phase composition of the diffusion layer formed at the interface. It is shown that after heating to 800 oС the diffusion layer consists of α + α’-Ti , an iron solid solution in titanium and a decarburized zone. When heated at the temperature range from 900 – 1000 oС, the composition of the diffusion layer is as follows: α + α’-Ti acicular structure, Fe2Ti and FeTi intermetallics, TiC titanium carbide, titanium solid solution in α-Fe and a decarburized zone.

Plasma electrolytic nitriding of alpha- and beta-titanium alloy in ammonia-based electrolyte

Abstract The structure of alpha- and beta-titanium alloy, its microhardness, surface roughness, wear and corrosion resistance after anodic plasma electrolytic nitriding (PEN) in electrolyte containing ammonia were investigated. An X-ray diffractometer and a scanning electron microscopy (SEM) were used to characterize the phase composition of the modified layer and its surface morphology. Tribological properties of nitrided titanium alloy and their corrosion resistance are investigated. It was shown that the electrolyte containing ammonia and ammonium chloride provided the saturation of alloy with nitrogen and oxygen and formation TiO2 with rutile structure and nitrogen solid solution in titanium. The anodic PEN at 800 °C during 5 min results in an increase in microhardness to 520 HV and a decrease in surface roughness by 4 times owing to anode dissolution of titanium. Friction coefficient of nitrided samples can be 4.4 times reduced through sliding with speed of 0.49 m/s and load of 208.6 N. These regimes enable to diminish wear rate of titanium alloy samples after their wear testing by 4 orders. The decrease in the sliding speed and load leads to the rise of friction coefficient and wear rate.

DIFFUSION COATINGS OF TITANIUM AND ALUMINUM BARRIER LAYER INVOLVING TIN ON STEEL 12CR18NI10TI

Phase and chemical compositions, structures and microhardness of diffusion coatings, containing titanium and aluminium, were studied on samples of steel 12Cr18Ni10Ti. Depending on the type of treatment the multilayer coatings on titanium carbide and nitrite base, intermetallics and oxides of titanium, aluminium, nickel, chromium, iron, as well as solid solutions of titanium and aluminium in austenite are formed in steel. It was found that during chemical-thermal treatment the titanium nitrite layer has a function of a barrier, delaying the aluminium and titanium diffusion into a base and the base components – into a coating.

DIFUSION POWDER Ti – Al-SILICONIZING OF STEEL 12Cr18Ni10Ti UNDER REDUCED PRESSURE

The phase and chemical composition, structure and microhardness, diffusion of multilayer coatings containing titanium, aluminum and silicon were examined at samples of steel 12Cr18Ni10Ti. It was established that the coating was formed on the basis of intermetallic compounds, carbides and titanium nitrides, as well as a solid solutions of titanium, aluminum, silicon, nickel and chromium in the austenite substrate.

Microstructure, Phase Transformation, Precipitation Behavior and Mechanical Properties of P/M Cu40Zn–1.0 wt% Ti Brass Alloy via Spark Plasma Sintering and Hot Extrusion

The effect of titanium addition on the microstructure and mechanical properties of brass Cu40Zn has been studied via the powder metallurgy (P/M) route. The water-atomized Cu40Zn–1.0 wt% Ti alloy powder was consolidated at different temperatures in the range of 400–600 °C using spark plasma sintering (SPS) and hot extrusion subsequently. Results show that the super-saturated solid solution titanium element in rapidly cooled brass Cu40Zn powder created high chemical potential for a precipitate reaction, showing significant grain refinement effects on the consolidated Cu40Zn matrix. Consequently, excellent mechanical properties were obtained by precipitation hardening and work hardening after sintering and extrusion, with yield strength of 390 MPa, ultimate tensile strength of 617 MPa, and Vickers micro-hardness of 192 HV, which are 28.7%, 23.4%, and 23.9% higher values than those of extruded Cu40Zn brass, respectively.

粉末冶金法を用いたカーボンナノチューブ分散Cu-Ti合金の組織と機械的および電気的特性

Microstructural and electrical properties of copper alloy (Cu-Ti) with carbon nanotubes (CNTs) prepared by powder metallurgy (P/M) process have been investigated. The Cu-0.5 mass% Ti pre-alloyed powder was made by water atomization process. The powders coated with un-bundled CNTs by using the zwitterionic surfactant solution containing CNTs were consolidated at 1223 K in vacuum by spark plasma sintering, and then extruded at 1073 K. The P/M Cu-Ti alloy without CNTs (monolithic alloy) had 202 MPa yield stress (YS) and 42.5 International-Anneld-Cupper-Standard % (IACS%) conductivity. The extruded Cu-Ti composite alloy containing CNTs revealed small decreased of YS compared to the monolithic Cu-Ti alloy. On the other hand, the composites revealed a higher electrical conductivity than that of the monolithic alloy. For example, Cu-Ti with 0.19 mass% CNTs showed 175.8 MPa YS and 83.5 IACS% conductivity. In the case of the Cu-Ti composite with CNTs, intermetallic compounds such as Cu4Ti and TiC were observed around CNTs by TEM-EDS analysis. The amount of the titanium solid solution in the above Cu-Ti composite alloy matrix was 10 % of the monolithic Cu-Ti alloy, and resulted in the remarkable increment of its electrical conductivity.