Showing papers on "Titanium powder published in 2011"

Interstitial elements in titanium powder metallurgy: sources and control

Abstract: The effect of interstitials on the mechanical properties of cast and wrought titanium alloys has been extensively reported but less information is available on the effect of contamination during PM processing. The sources of interstitial contamination when processing titanium powders by compaction, isostatic pressing, powder injection moulding (PIM) and innovative foaming processes are reviewed, focusing specifically on oxygen. The initial powder characteristics (surface area, size), process parameters (time, temperature) and environment (atmosphere, binder, support) may all have significant impact on the final interstitial content. It is, therefore, important to identify and control the sources of contamination by interstitials. A case study on PIM is provided to illustrate the relative contribution of the different sources.

Sintering of Ti-10V-2Fe-3Al and mechanical properties

Abstract: A comprehensive study has been made of the sintering and microstructural evolution of Ti–10V–2Fe–3Al compacted from titanium and master alloy powder blends. The densification of Ti–10V–2Fe–3Al at ≤1300 °C occurs by solid-state sintering with apparent activation energy of 163 ± 13 kJ/mol, which falls into the reported activation energy range for the self-diffusion of titanium. The sintered density depends primarily on the titanium powder size while the sintered microstructure and mechanical properties depend mainly on the master alloy type or diffusion of vanadium. The real challenge for the fabrication of Ti–10V–2Fe–3Al by sintering is not densification, which is trivial with relatively fine titanium powder. Rather, it is the realisation of a desired microstructure through master alloy selection or design of the sintering pathway, which determines the distribution of the principal alloying element V, a slow diffuser in β-Ti. This distinguishes it from the sintering of lean alloys, where the focus has predominantly been on densification. The use of 10V–2Fe–3Al master alloy produced more uniform microstructures and therefore much better ductility than the use of 85V–15Al at similar densities.

Key characteristics of hydride–dehydride titanium powder

Abstract: Titanium powders produced via the hydride–dehydride process are described with reference to the markets that they serve, on the basis of more than 20 years of operating experience at Reading Alloys. Raw material selection and downstream finishing play important roles in determining key characteristics of the finished powder. Resultant chemistry, morphology and particle size distributions are discussed.

Titanium dioxide doped with transition metals (M x Ti 1− x O 2 , M: Ni, Co): synthesis and characterization for its potential application as photoanode

Abstract: This study presents the synthesis of TiO2 doped with different amounts of Co and Ni, starting from a simple metallic titanium powder. A successful electrophoretic deposition of these materials on ITO electrodes was achieved for its potential application as photoanodes. EDX, diffuse reflectance UV–Vis spectroscopy, and XRD measurements gave information on the chemical composition of the material and the location of the Ni or Co within the crystal structure of TiO2. Raman spectroscopy suggests that for a higher content of doping metal above a defined percentage, the formation of metal oxide is promoted. A preliminary study of photoelectrocatalytic orange dye degradation shows higher color removal efficiency as compared to the commercial TiO2 material.

Electrical conductivity of metal powders under pressure

Abstract: A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called ‘equivalent simple cubic system’, was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

Manufacture of near-net shape titanium alloy articles from metal powders by sintering with presence of atomic hydrogen

Abstract: A process including: (a) forming a powder blend by mixing titanium powders, (b) consolidating the powder blend by compacting to provide a green compact, (c) heating the green compact thereby releasing absorbed water from the titanium powder, (d) forming β-phase titanium and releasing atomic hydrogen from the hydrogenated titanium by heating the green compact in an atmosphere of hydrogen emitted by the hydrogenated titanium, (e) reducing surface oxides on particles of the titanium powder with atomic hydrogen released by heating of the green compact, (f) diffusion-controlled chemical homogenizing of the green compact and densification of the green compact by heating followed by holding resulting in complete or partial dehydrogenation to form a cleaned and refined compact, (g) heating the cleaned and refined green compact in vacuum thereby sintering titanium to form a sintered dense compact, and (h) cooling the sintered dense compact to form a sintered near-net shaped article.

Compaction of Titanium Powders

Abstract: Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

Preparation method for porous titanium

Abstract: The invention discloses a preparation method of porous titanium, wherein, the preparation method comprises the following steps: step1: preparing premixed liquid; step2: preparing slurry; step3: performing processes of gel solidifying and injection molding; step4: removing the adhesive by isostatic pressing; step5: sintering. The beneficial effects brought by the technical schemes of the embodiment in the invention are: by using a heat reversible transformation mechanism of the monomer slurry without adding an initiator, an organic matter is performed a physical crosslinking; slurry forms a flow state at the temperature of 60 DEG C and then injected into a die, and is formed by converting physical gel into a solid state below the temperature of 60 DEG C; nanometer level titanium powder used as a raw material is capable of substantially increasing the strength and hardness of the material, simultaneously reducing the thermal conductivity of the material. The prepared porous titanium product has uniform distributed pore diameters, a three dimensional network with a regular microstructure can be formed, and is capable of effectively reducing the sintering temperature and the sintering time, and improving the mechanical properties of porous titanium and processing property of the green compact as well as reducing the energy consumption.

Ignition of Titanium Powder Layers by Electrostatic Discharge

Abstract: Titanium powder heating and ignition by an electrostatic discharge (ESD) or spark was investigated. The effect of powder layer thickness and morphology was determined. Ti powder was chosen for these experiments because it is commonly found in energetic formulations, used for materials preparation by self-propagating high-temperature synthesis, and is extensively used in powder metallurgy. Two Ti powders were used: spherical powder with a volume mean diameter of 82 µm and sponge powder with a volume mean diameter of 30 µm. ESD current and voltage were measured in real time; powder ignition was characterized using an optical sensor and photographs of the produced burning particles. Different ignition modes were observed for powders with different morphologies and placed in layers with different thickness. For both spherical and sponge Ti powders prepared as monolayers, ESD initiation resulted in fragmentation of the initial particles. Produced particle fragments were ejected from the sample holder and burne...

Method for preparing titanium diboride and titanium carbide enhanced iron-based wear resistant composite paint

Abstract: The invention relates to a method for preparing a titanium diboride and titanium carbide enhanced iron-based wear resistant composite paint. The method comprises the following steps: selecting a plurality of materials from iron powder, titanium powder, ferrotitanium powder, boron carbide powder, ferroboron powder and graphite powder to mix and form mixed powder containing the four elements of iron, titanium, boron and carbon, adding or not adding one or more of Ni, Cr, Si and Y2O3, placing the obtained powder in a ball mill or mixer to mix evenly; then using the mixed metal powder to form paste, coating the paste on the surface of carbon steel to form a layer of preset powder; and then adopting laser heating to irradiate the preset powder and ensure that the preset powder and partial carbon steel base material are molten to form a molten bath and perform metallurgical reaction. The preparation method is simple and the prepared composite paint has high hardness and excellent wear resistance.

Wear Behavior of Modified Surface Layer Produced by TIG Melting of Preplaced Ti Powder in Nitrogen Environment

Abstract: The formation of hard surface layer on steel provides a protective coating against wear, thermal loads and corrosion. In the present work a hard composite layer is formed on steel surfaces by preplacement of titanium powder and melted under nitrogen environment. Surface melting was conducted using TIG torch with different energy inputs. The microstructure and the morphology of the melt tracks were investigated using SEM and X-ray diffraction. The in-situ melting of titanium powder in nitrogen atmosphere produced dendritic microstructure of titanium nitride. The melt layer contained dispersed TiN, Ti2N dendrites highly populated at the surface compared to the deeper melt and gave a maximum surface hardness of around 1927 Hv. The wear property of the melt track was investigated using pin-on-disk tribometer at room temperature. The modified surface layer gave a low friction value of 0.12 and wear rate of 0.007895 ×10-4 compared to 1.648 × 10-4 mm3/N/m for the uncoated steel surface.

Innovative consolidation of titanium and titanium alloy powders by direct rolling

Abstract: R&D efforts at CSIRO, Australia, into the production of ‘lower cost’ titanium powders are complemented by a strong, downstream PM programme One of these efforts has focused on the direct powder rolling of commercially pure (cp) titanium powder with a view to the continuous production of fully dense strip Considerable research is also being undertaken to produce titanium alloy strip, initially from the Ti–6Al–4V alloy, using this process An experimental design approach has been employed to establish key parameters, maximise the process window and meet property specifications Demonstration of a proof-of-system at pilot scale is well advanced and the focus is now shifting to seeking industrial engagement with a view to collaboration, technology transfer and commercialisation of the technology The current status of the technology is surveyed including aspects of the associated market trends and commercial feasibility

Preparation method for wear-resistant corrosion-resistant coating from coarse granular titanium-carbide-based powder

Abstract: The invention provides a preparation method for wear-resistant corrosion-resistant coating from coarse granular titanium-carbide-based powder, belonging to the field of surface coating preparation. The preparation method comprises the following steps: weighing titanium powder, graphite powder, and other metal component raw material powder according to a ratio, ball-milling mixed powder, compacting to form a block, adding the block to a reactor, igniting the compacted block for self-propagating reaction to obtain a porous titanium-carbide-based block, removing surface pollutants of the titanium-carbide-based block, crushing residual product, screening to obtain 20-50 mu m titanium-carbide-based rigid granular powder material, mixing the coarse granular powder, binding alloy powder and an adhesive to obtain slurry, applying the slurry on steel piece surfaces, drying and cladding to obtain the wear-resistant corrosion-resistant coating. The preparation method provided by the invention is energy-saving and environment-friendly, has the characteristics of low price, good binding between rigid granules and binding metal, high wear resistance and the like, and is suitable for industrial production.

Brake block for high-speed train and preparation method thereof

Abstract: The invention provides a brake block for a high-speed train and a preparation method thereof, which belongs to the technical field of powdery metallurgical materials and is used for solving the problem of unstable friction factor of a semimetal-based composite brake block. The improved brake block is made from the following powdery raw materials according to parts by weight: 25 to 55 parts of copper powder, 5 to 20 parts of nickel powder, 4 to 12 parts of iron powder, 1 to 4 parts of manganese powder, 1 to 9 parts of chromium powder, 5 to 20 parts of graphite, 5 to 10 parts of carborundum, 1 to 8 parts of tungsten powder, 3 to 6 parts of titanium pigment, 3 to 10 parts of silicon dioxide, 1 to 4 parts of titanium powder, and 1 to 5 parts of aluminum powder. The raw materials are technically pure, and the grain size is 200 meshes or less. The brake block is made from metal-based composite raw materials, the raw material of the substrate is copper alloy with high thermal conductivity andgood plasticity. With the reasonable adoption of other materials and optimized proportioning thereof, the made brake block has the following characteristics: 1. base body with good thermal shock resistance and no crazing, 2. stable change of friction factors under the condition of friction temperature rise, and 3. low attrition rate and long service life.

Technique for preparing low-oxygen high-purity titanium powder by novel HDH method

Abstract: The invention relates to a novel manufacturing technique of low-oxygen high-purity titanium powder by HDH method, comprising that oxygen reducing agents are respectively added in the hydrogenating and dehydrogenating processes of the hydrogenating and dehydrogenating technique; air moisture is controlled during the whole production process so as to control the moisture of the production field to be not more than 40, thereby producing high-quality titanium powder product with lower oxygen content. -60-mesh titanium powder produced by the technique of the invention has the oxygen content of 0.15% and the nitrogen content of 0.02%.

Preparation of titanium carbide micro powder

Abstract: The invention discloses a method for preparing titanium carbide micro powder Titanium powder and sucrose with the mass ratio of 1 to 16:1 are mixed, milled with balls, dried, then carbonized in boiling oil, dried, removed with oil and ignited, and then an self-propagating reaction happens and titanium carbide is produced The method mainly utilizes the sucrose to cover titanium powder particles, then carbonization is carried out to generate carbon which is used for covering the titanium powder particles; the contact area between carbon and titanium is fairly large and a carbon layer is remained between the titanium powder particles and particles, therefore, during the self-propagating reaction, the carbonized titanium powder is not easy to agglomerate and the technique process is simple and easy to be controlled

Method for preparing metallic titanium powder by reducing titanium dioxide with magnesium

Abstract: The invention relates to a method for preparing metallic titanium powder by reducing titanium dioxide with magnesium, which comprises the following steps: using titanium dioxide as a raw material, using calcium chloride and the like as additives and using magnesium as a reducer, volatilizing the magnesium metal into magnesium steam at the vacuum degree of 10-30 Pa and the temperature of 800-1200 DEG C to react with the titanium dioxide placed on an upper layer to acquire titanium metal and magnesium oxide, washing with acid and vacuum drying to obtain the metallic titanium powder.

Preparation method of TiC granule reinforcing Ti-Al-Sn-Zr-Mo-Si high-temperature titanium alloy composite material plate

Abstract: The invention relates to a preparation method of a TiC granule reinforcing Ti-Al-Sn-Zr-Mo-Si high-temperature titanium alloy composite material plate, relating to a preparation method of a titanium alloy composite material plate and solving the problems of high oxygen content and poor plasticity of TiC granule reinforcing titanium-base composite materials prepared by the traditional nonconsumableelectrode melting preparation method. The preparation method comprises the following steps of: calculating the amounts of titanium powder, graphite powder and other materials according to the volume percent of TiC granules and Ti-Al-Sn-Zr-Mo-Si high-temperature titanium alloys which are contained in the composite material plate; then preparing the titanium powder and the graphite powder into prefabricated blocks; then placing the prefabricated blocks and the other materials into a vacuum water-cooling copper crucible induction melting furnace for melting so as to obtain cast ingots; and then carrying out forging, rolling and heat treatment on the cast ingots to obtain the composite material plate with the oxygen content of 200 ppm-800 ppm and 2-10 percent of elongation percentage.

Metal injection molding of titanium for medical and aerospace applications

Abstract: Mixing of titanium powder and thermoplastic binders creates a feedstock that is injection molded similar to plastic, has a chemical and thermal debinding process, and then is sintered to form a net-shape or near-net shape part. TiJet Medizintechnik GmbH (TiJet) developed and uses its own feedstock and powder processing technology to achieve desired mechanical properties. This paper explains the theory of the process and the possibilities that result from the development of this new powder processing technology, such as new alloys, design possibilities, etc. Discussed will be the microstructure, chemical composition, and mechanical properties of the manufactured parts.

Oxygen partial pressure change with metal titanium powder nitriding under microwave heating

Abstract: Microwave heating was applied to metal titanium powders at high oxygen partial pressure (10−5 atm) and the partial pressure of exhaust-gas were measured using an oxygen sensor made of solid electrolyte. During the application of the heating, the pressure decreased to an order of 10−10 atm and quickly increased to an order of 10−5 atm and then oxygen emission peaks were observed. Furthermore, the nitriding mechanism was discussed for Ti14O13 model in terms of quantum chemistry. The quantum-chemical simulation showed that Ti–O bonding of titanium oxide is anti-bonding and consists of 3d orbital. The orbital becomes steady state by removing an oxygen atom from the model.

Formation of TiN Dispersed Composite Layer on Steel Surfaces by Titanium Powder Preplacement and TIG Surface Melting Processes

Abstract: The possibility of forming a TiN dispersed composite layer on steel was studied by preplacement of titanium powder on steel surface and melting under TIG (Tungsten inert gas) torch in a reactive environment. The surface melting of preplaced 1.8 mg/mm2 Ti powder was performed under TIG torch with energy inputs of 324,378 and 432 J/mm in a pure nitrogen environment. With these melting conditions, the powder layer along with a thin layer of the substrate melted and produced a melt pool of around 1mm thickness. The resolidified melt layer consisted of dispersion of TiN dendrites in ferrite matrix and thus a composite of TiN in ferrite is created on the steel surface. The concentration of dendrite population was found to be higher nearer the melt surface compared to the deeper depth. A maximum surface hardness of about 2000 Hv was developed at the surface when glazed with an energy input of 432 J/mm and the hardness decreased gradually away from the surface. The hardness development is directly related to the concentration of TiN dendrites.

Titanium powder production process

Abstract: The invention provides a crystalline Ti powder produced in a molten salt medium, said powder comprising predominantly particles of single α-Ti crystals that are directly applicable in powder metallurgy. The invention extends to continuous process for the production of titanium powder in a molten salt medium by known reaction mechanisms, said process including the steps of reacting in a first reaction zone in a molten salt TiCl4 with reactants selected from Ti particles, a substoichiometric quantity of reducing agent, and a mixture of titanium metal and a substoichiometric amount of reducing agent, to form Ti sub-chloride, transferring Ti sub-chloride containing salts from the first reaction zone into a second reaction zone, which is electrically, ionically, or both electrically and ionically isolated from the first reaction zone, reacting in the second reaction zone the Ti sub-chloride with molten reducing metal to form dispersed Ti powder and molten salt, and withdrawing a portion of a suspension of Ti powder in molten salt from the second reaction zone to downstream processing units to separate the Ti powder from the salt and optionally recycle a portion of said Ti powder in molten salt to the first reaction zone. The invention further extends to an apparatus for the process of the invention.

Study of Compaction and Ejection of Hydrided-Dehydrided Titanium Powder

Abstract: Three similar varieties of pure Ti hydride-dehydried (HDH) powders were tested for the understanding of the variables that have an influence on the compaction process of Ti powders. The study shows that small differences in the characteristics of the powders lead to very different behaviours in the compaction stage. Compressibility curves, friction with the die walls and ejection forces are discussed in this study. The results are compared with a commercial iron powder as a reference to complete the discussion, as well as to show the enhancements and modifications that should be performed in Ti powders to design an optimized powder suitable for being pressed in an industrial process.

Igniting powder composition for igniters

Abstract: An ignition powder composition for igniter of which friction sensitivity can be lowered with the required firing current sensitivity being achieved is provided as ignition powder for an igniter that is activated by an electrical signal. The ignition powder composition for igniter contains metal hydride (A); metal powder (B) that is one or more selected from the group consisting of tungsten powder, molybdenum powder, aluminum powder, titanium powder, and magnesium powder; and perchlorate (C).

Preparation method of tungsten titanium alloy plate for sputtering target

Abstract: The invention discloses a preparation method of a tungsten titanium alloy plate used for sputtering target, comprising the following steps: 1. placing tungsten powder and titanium powder into a three-dimensional mixer for mixing; molding by a cold isostatic pressing machine to obtain a tungsten titanium alloy target green body; 2. placing the tungsten titanium alloy target green body into a vacuum hotpressing sintering furnace for preparing a tungsten titanium alloy plate blank; 3. polishing the surface of the tungsten titanium alloy plate blank to be smooth and cutting into the required size; and 4. placing the cut tungsten titanium alloy plate blank into a vacuum annealing furnace for annealing to obtain the tungsten titanium alloy plate. In the preparation process of the tungsten titanium alloy plates, the tungsten titanium alloy powder is fully utilized, and needs little mechanical process at the later stage; the finished-product rate is high; and pollutants, such as waste materials and waste acid and the like can not be generated.