Abstract: The invention is a process for simultaneously improving at least two mechanical properties of mill-processed (.alpha.+.beta.) titanium alloy, which may or may not contain silicon, which includes steps of heat treating the mill-processed titanium alloy such that the (.alpha.+.beta.) microstructure of said alloy is transformed into an (.alpha.+.alpha..sub.2 +.beta.) microstructure, preferably containing no silicides. The heat treating steps involve subjecting the mill-processed titanium alloy to a sequence of thermomechanical process steps, and the mechanical properties which are simultaneously improved include (a) tensile strength at room, cryogenic, and elevated temperatures; (b) fracture toughness; (c) creep resistance; (d) elastic stiffness; (e) thermal stability; (f) hydrogen embrittlement resistance; (g) fatigue; and (h) cryogenic temperature embrittlement resistance. As a consequence of the process, the (.alpha.+.alpha..sub.2 +.beta.) microstructure contains equiaxed alpha phase strengthened with .alpha.

Abstract: A titanium alloy possessing an equiaxial two-phase (.alpha.+.beta.) structure having an average grain size in the range of from 1 .mu.m to 10 .mu.m is obtained by a prescribed heat treatment of a titanium alloy material having a composition represented by the following formula 1,Ti.sub.100-a-b-c-d-e Al.sub.a V.sub.b Fe.sub.c Mo.sub.d O.sub.e(1)(wherein a, b, c, d, and e respectively satisfy the relations, 3.0.ltoreq.a.ltoreq.5.0, 2.1.ltoreq.b.ltoreq.3.7, 0.85.ltoreq.c.ltoreq.3.15, 0.85.ltoreq.d.ltoreq.3.15, and 0.06.ltoreq.e.ltoreq.0.20). The titanium alloy is formed in prescribed shape and size and finished with a mirror surface. It is produced by a method which comprises subjecting a titanium alloy material having a composition represented by the formula 1 to a solid solution treatment at a temperature in an .alpha.+.beta. range 25.degree. C.-100.degree. C. lower than the .beta.

Abstract: A method for producing fine-grained lamellar microstructures in powder metallurgy (P/M) and wrought gamma titanium aluminides comprises the steps of: (a) a cyclic heat treatment at a maximum temperature in the range of about 10.degree. C. above to about 10.degree. C. below the alpha-transus temperature (T.sub..alpha.) of the alloy, and (b) a secondary heat treatment of thus cyclically heat treated alloy at a temperature between 750.degree. C. and 1050.degree. C. for 4 to 100 hours. For cast gamma alloys, the method comprises additionally the step of a solution treatment at a temperature in the range of about 30.degree. C. to 70.degree. C. above T.sub..alpha. followed by a water or an oil quench before the two steps described above. The alloys with the resulting fine-grained lamellar microstructure have an advantageous combination of mechanical properties--tensile strength, ductility, fracture toughness, and creep resistance.

Abstract: A gamma titanium aluminide alloy article is produced from a piece of cast gamma titanium aluminide alloy by consolidating the gamma titanium aluminide alloy piece at a temperature above the eutectoid to reduce porosity therein, preferably by hot isostatic pressing. The piece is first heat treated at a temperature above the eutectoid for a time sufficient to form a structure of gamma grains plus lamellar colonies of alpha and gamma phases, and thereafter second heat treated at a temperature below the eutectoid to grow gamma grains within the colony structure, thereby reducing the effective grain size of the colony structure. There may follow an additional heat treatment just below the alpha transus to reform any remaining colony structure to produce a structure having isolated alpha-two laths within gamma grains.

Abstract: A hollow article is made by providing and diffusion bonding the opposing parts of an article made of an alpha-beta titanium alloy. Hydrogen is introduced into the surface of an internal cavity before, during, or after diffusion bonding. The article is heat treated with the hydrogen present, typically by solution treating and aging the hydrogen-containing bonded article. The result is the production of a microstructure at the internal surface of the cavity that is resistant to fatigue-crack initiation, while retaining a microstructure throughout the rest of the article that is resistant to fatigue-crack propagation. After heat treating, the hydrogen is removed from the article, and any further heat treating and other operations are completed.

Abstract: This invention relates to a catalytic fuel composition capable of reducing pollutants in the combustion gasses generated upon combustion of the same. A catalytic material is combined with a liquid, petroleum-based fuel, mixed and solid particles are separated out to give the catalytic fuel product. The catalytic material predominantly comprises a plagioclase feldspar belonging mainly to the albiteanorthite series, and contains small amount of mica, kaolinite and serpentine, and optionally contains magnetite. An alloy material is also disclosed, comprising a mixture of the above-described catalytic material and a metal. The alloy material exhibits unique properties relative to the metal component alone, such as increased tensile strength, improved heat resistance, improved acid resistance, improved corrosion resistance, as well as exhibiting unusual conductive properties.

Abstract: Method for heat treating a metal in which argon gas is selectively injected into the cooling zone of a heat treating apparatus when the temperature therein is above the level at which significant nitriding will occur.

Abstract: A titanium aluminide component is disclosed based on intermetallic phases of the system titanium-aluminum and having an aluminum content between 42 at. Percent and 53 at. Percent. The titanium aluminide component has on its surface a lamellar, eutectoid Ti.sub.3 Al/TiAl structure. Also disclosed is a process for preparing the titanium aluminide component.

Abstract: A titanium matrix composite having eutectically formed titanium alloy reinforcement containing at least two of the elements of silicon, aluminum, zirconium, manganese, chromium, molybdenum, carbon, iron, boron, cobalt, nickel, germanium and copper.

Abstract: The microstructure of alpha-2 and orthorhombic titanium aluminide alloy cast and ingot metallurgy articles is refined by: (a) hydrogenating the article at a temperature at or slightly below the .beta.-transus temperature of the alloy; (b) cooling the article, under a positive partial pressure of hydrogen, to a temperature about 20 to 40 percent below the .beta.-transus; and (c) dehydrogenating the article.

Abstract: An article comprises a Cr-bearing, predominantly gamma titanium aluminide matrix including second phase dispersoids, such as TiB.sub.2, in an amount effective to increase both the strength and the ductility of the matrix.

Abstract: A TiAl-based intermetallic compound has a metallographic structure which includes a region A having fine .beta.-phases dispersed in a .gamma.-phase. The volume fraction Vf of the .beta.-phases in the region A is set equal to or more than 0.1% (Vf.gtoreq.0.1%). Thus, the .beta.-phases can exhibit a pinning effect to prevent a transgranular pseudo cleavage fracture in the .gamma.-phase, thereby providing an enhanced high-temperature strength of the TiAl-based intermetallic compound.

Abstract: This is a method for heat assisted forming, annealing, and hardening 360.degree. sheet metal shapes in a clean environment in a single facility that results in dimensionally correct, cost-effective, contaminant free parts.

Abstract: The fracture resistance of titanium alloy matrix composites is increased by one of two methods. One method comprises the steps of consolidating a titanium alloy-fiber preform under suitable conditions to provide a metal matrix composite and thermally treating the thus-prepared composite at a temperature above the beta-transus temperature of the alloy for a brief time. In the second method, a composite having increased fracture resistance is produced by consolidating an alloy-fiber preform at a temperature above the normal consolidation temperature for a time less than the normal consolidation time.

Abstract: A non-burning Ti-V-Cr alloy which is heat treated to decrease its susceptibility to embrittlement in gas turbine engine compressor applications. The invention heat treat cycle consists of an isothermal holding period below the alpha solvus temperature, a slow ramp down to a lower temperature, a second holding period at a lower temperature, a third ramp down to an even lower temperature, and a final holding period at the third temperature. Other suitable heat treat cycles within the concept of the invention include a single holding period below the alpha solvus temperature double holding periods below the alpha solvus temperature with a ramp from a higher to a lower temperature and a continuous ramp below the alpha solvus temperature with no holding period.

Abstract: Surface and near surface hardened medical implants are provided. These implants are fabricated from titanium alloys that contain an amount of zirconium sufficient to permit the formation of a significant amount of zirconium oxide at the surface of the implant to cause surface hardening. Further, the zirconium-containing titanium alloy implants are characterized in having an alloy core with an oxygen-rich layer surrounding the core, and a surface layer, overlying the oxygen-rich layer, including mixed oxides of the metals present in the alloy. A zirconium-rich interface may sometimes be present between the oxygen-rich layer and the mixed-oxide surface layer. The method of producing these surface hardened implants includes the steps of heating the implant in an oxygen containing environment at a temperature sufficient to allow oxygen to diffuse to and react with the implant surface and near surface.

Abstract: Ti powders and Al powders are combined to prepare a mixture of 40.about.55 at % of Al and the balance of Ti. After CIP and degassing, plastic working by hot extrusion is applied to form a shaped mixture of Ti and Al. The shaped mixture is then processed by HIP to synthesize titanium aluminide while diffusing Al into the Ti structure to form an Al.sub.2 O.sub.3 phase occurring from both the reaction between Al and oxygen contained in the Ti structure and the oxides on the Al surface, and to disperse the Al.sub.2 O.sub.3 to form the Al.sub.2 O.sub.3 protective film. With the reaction between Al and oxygen contained in the Ti structure and with the "Pegging" effect, both the Al.sub.2 O.sub.3 a phase formed at the grain boundaries of crystals or in the crystal grains of titanium aluminide and the Al.sub.2 O.sub.3 phase existing on the surface of raw material Al powder peg the surface Al.sub.2 O.sub.3 film to the surface of the titanium aluminide body.

Abstract: A titanium matrix composite having eutectically formed titanium alloy reinforcement containing at least two of the elements of silicon, aluminum, zirconium, manganese, chromium, molybdenum, carbon, iron, boron, cobalt, nickel, germanium and copper.

Abstract: A titanium-base alloy, and weldment made therefrom, consisting essentially of, in weight percent, aluminum 4 to 5.5, preferably 5.0, tin up to 2.5, preferably 0.5 to 1.5 or 1; zirconium up to 2.5, preferably 0.5 to 1.5 or about 1; vanadium 0.5 to 2.5, preferably 0.5 to 1.5 or about 1; molybdenum 0.3 to 1, preferably, 0.66 to 1 or about 0.8; silicon up to 0.15, preferably 0.07 to 0.13 or about 0.1; oxygen 0.04 to 0.12, preferably 0.07 to 0.11 or about 0.09; iron 0.01 to 0.12, preferably 0.01 to 0.09 or about 0.07 and balance titanium and incidental impurities.

Abstract: A method for producing single-phase intermetallic phases, which melt incongruently within a temperature range of 900.degree. to 2,000.degree. K., with a homogeneity range of .ltoreq.10 atom % at room temperature by co-reduction is described. The exothermic reaction of the calciothermal reduction is adjusted by altering the oxide content of the reaction mixture, the composition of which corresponds to the desired single-phase alloy, in such a way that the temperature condition T.sub.m >T.sub.R .gtoreq.0.9 T.sub.m (in .degree. K.) is fulfilled, T.sub.m being the melting temperature of the intermetallic phase and T.sub.R the reaction temperature. The components of the reaction mixture, with the exception of calcium, have an average particle size of .ltoreq.75 .mu.m. The reaction product at the end of the exothermic reaction is tempered at a temperature which is at least 0.7 times the melting temperature T.sub.m of the desired, single-phase alloy, measured in .degree. K.

Abstract: A process for producing amorphous alloy materials having high toughness and high strength from various alloy powders, thin ribbons or bulk materials consisting of an amorphous phase by heating them to a temperature at which intermetallic compounds or other compounds are not produced. During this heating, fine crystal grains consisting of a supersaturated solid solution made of a main alloying element and additive elements and having a mean grain diameter of 5 nm to 500 nm are precipitated and uniformly dispersed in a volume percentage of 5 to 50% throughout an amorphous matrix. In the process, when deformation, pressing or other working is simultaneously conducted with the heating, consolidation or combining of the resultant alloy materials can also be effected in the same production procedure. The amorphous alloy used in the production process preferably comprises Al, Mg or Ti as a main element and, as additive elements, rare earth elements and/or other elements.

Abstract: Creep resistant titanium aluminide alloy article consisting essentially of, in atomic %, about 45 to about 48 Al, about 1.0 to about 3.0 Nb, about 0.5 to about 1.5 Mn, about 0.25 to about 0.75 Mo, about 0.25 to about 0.75 W, about 0.15 to about 0.3 Si and the balance titanium. The article has a heat treated microstructure including gamma phase, alpha-two phase and at least one additional particulate phase including, one or more or W, Mo, and Si dispersed as distinct regions in the microstructure.

Abstract: A Ti-Al intermetallic compound is prepared from a mixture of about 40 to 52 atomic % Ti, about 48 to 60 atomic % Al, and 10 to 3000 atomic ppm of at least one of P, As, Se, or Te. The mixture is melted and then solidified. The solidified product is annealed to form a uniform microstructure.

Abstract: A method for manufacturing superplastic forming/diffusion bonding tools and a wide range of other aerospace parts by forming a titanium aluminide interface layer from ion vapor deposition is disclosed.

Abstract: The present invention relates to a process in which a metal or metal alloy is thermal spray coated onto a base alloy material prior to hot working. More specifically, the invention relates to the use of plasma coating of titanium over a titanium alloy plate for improved hot workability. This combination allows the crack-sensitive base alloy to be rolled with a minimum of surface and edge cracks. In addition, by using a plasma sprayed titanium coating there is a reduction in the roll force required to reduce the material during the hot working process.

Abstract: A titanium aluminide is composed of 31 to 34 mass % of Al, 1.5 to 3.0 mass % of Fe, 0.5 to 2.0 mass % of V, 0.18 to 0.35 mass % of B with remainder being Ti and inevitable impurities. The 0.5 to 2.0 mass % of V may be replaced with a 1.0 to 3.0 mass % of Mo or a 0.3 to 1.5 mass % of Cr. By precision casting this alloy, a novel titanium aluminide alloy is obtained in which numerous whisker-like Ti--B compound are uniformly dispersed. The titanium aluminide alloy does not possess a coarse lamellar structure which would cause cracking.

Abstract: The high temperature alloy is intended for machine components subjected to high mechanical and thermal stress. It is essentially based on doped TiAl and has the following composition:Ti.sub.x El.sub.y Me.sub.z Al.sub.1-(x+y+z),in which El=B, Ge or Si and Me=Co, Cr, Ge, Hf, Mn, Mo, Nb, Pd, Ta, V, W, Y, and/or Zr and:______________________________________ 0.46 .ltoreq.x .ltoreq.0.54, 0.001 .ltoreq.y .ltoreq.0.015 for El = Ge and Me = Cr, Hf, Mn, Mo, Nb, Ta, V and/or W, 0.001 .ltoreq.y .ltoreq.0.015 for El = Si and Me = Hf, Mn, Mo, Ta, V and/or W, 0 .ltoreq.y .ltoreq.0.01 for El = B and Me = Co, Ge, Pd, Y and/or Zr, 0 .ltoreq.y .ltoreq.0.02 for El = Ge and Me = Co, Ge, Pd, Y and/or Zr, 0.0001 .ltoreq.y .ltoreq.0.01 for El = B and Me = Cr, Mn, Nb and/or W, 0.01 .ltoreq.z .ltoreq.0.04 if Me = an individual element, 0.01 .ltoreq.z .ltoreq.0.08 if Me = two or more individual elements and 0.46 .ltoreq.(x + y + z) .ltoreq.0.54.

Abstract: A TiAl alloy base melt including at least one of Cr, C, Ga, Mo, Mn, Nb, Ni Si, Ta, V and W and at least about 0.5 volume % boride dispersoids is investment cast to form a crack-free, net or near-net shape article having a gamma TiAl intermetallic-containing matrix with a grain size of about 10 to about 250 microns as a result of the presence of the boride dispersoids in the melt. As hot isostatically pressed and heat treated to provide an equiaxed grain structure, the article exhibits improved strength.

Abstract: A method of producing a part having high strength and improved ductility from a titanium alloy having a composition, in percent by weight, or Mo equivalent 5 to 13 and Al equivalent 3 to 8, the balance being titanium and impurities, comprising the steps of hot working an ingot of the alloy including a roughing down under heat and preparation of a blank under heat, preheating to a temperature situated above the real beta transus of the hot worked alloy, and then final working of at least a part of this blank, after which the blank obtained is subjected to a solution heat treatment and then aged. The hot worked blank is cooled from the preheating temperature to a temperature for the beginning of final working which, under the conditions of the cooling of the blank, is at least 50.degree. C. below the real beta tansus and at least 10.degree. C. above the temperature of appearance of the alpha phase, so that the final working is sufficient to end within the alpha nucleation range.

Abstract: The present invention provides a Ti--Al intermetallic compound sheet of a thickness in the range of 0.25 to 2.5 mm formed of a Ti--Al intermetallic compound of 40 to 53 atomic percent of Ti, 0.1 to 3 atomic percent of at least one of material selected from the group consisting of Cr, Mn, V and Fe, and the balance of Al, and a Ti--Al intermetallic compound sheet producing method comprising the steps of pouring a molten Ti--Al intermetallic compound of the foregoing composition into the mold of a twin drum continuous casting machine, casting and rapidly solidifying the molten Ti--Al intermetallic compound to produce a thin cast plate of a thickness in the range of 0.25 to 2.5 mm and, when necessary, subjecting the thin cast plate to annealing and HIP treating. The Ti--Al intermetallic compound sheet has excellent mechanical and surface properties.

Abstract: A Titanium base alloy with improved superplastic, hot workability, cold workability, and mechanical properties is provided. The alloy has about 4% Al and 2.5% V, with below 0.15% O, with 2% Fe and 2% Mo, 0.85.about.3.15 wt. % Mo, and at least one element from the group of Fe, Ni, Co, and Cr as beta stabilizing elements, and as contributing elements to the lowering of beta transus, finally to the improvement of the superplastic properties, and hot and cold workability, with the grain size of below 5 .mu.m. A method of making thereof is provided with the reheating temperature between beta transus minus 250.degree. C. and beta transus.A method of superplastic forming thereof is provided with the heat treating temperature between beta transus minus 250.degree. C. and beta transus.

Abstract: A method and apparatus for applying heat sufficient to permit plastic deformation of intermetallic material. The heat is applied to a fractional region of a workpiece, and then manipulations capable of causing the workpiece to deform are applied using conventional sheet metal forming equipment. The invention utilizes elevated forming temperatures to heat the fractional region of the intermetallic workpiece so that the fractional region has sufficient ductility to permit a plastic deformation required for the forming operation. The apparatus is a sheet metal-working machine which has been modified to provide the localized heating required to carry out the process of the present invention.

Abstract: Disclosed are a Ti--Al alloy including aluminum (Al) in an amount of 30 to 38% by weight, nitrogen (N) in an amount of 0.2 to 1.0% by weight, and titanium (Ti), substantially the balance, and a process for producing the same. Since the Ti--Al alloy includes the nitrogen in the predetermined amount, the microstructure of the Ti--Al alloy can be micro-fined and made into a uniform one, and accordingly the shrinkage cavities can be reduced remarkably. Therefore, the strength, the ductility or the like of the Ti--Al alloy can be improved remarkably. With the production process, it is possible to produce the Ti--Al alloy including the nitrogen in the predetermined range.

Abstract: A method to increase the fracture resistance of titanium alloy matrix composites which comprises thermally treating a composite at a temperature about 5 to 10% above the beta-transus temperature of the alloy for about 4 to 60 minutes.

Abstract: A TiAl composition is prepared to have high strength, high oxidation resistance and to have acceptable ductility by altering the atomic ratio of the titanium and aluminum to have what has been found to be a highly desirable effective aluminum concentration and by addition of chromium, boron, and tantalum according to the approximate formulaTi-Al.sub.46-48 Cr.sub.1-3 Ta.sub.2-4 B.sub.0.1-0.3.The alloy is cast to form a body and the body is HIPped to impart a desirable combination of properties thereto.

Abstract: Leaders are attached to opposite ends of a titanium foil or thin strip element and are partially coiled on respective reels spaced at opposite sides of a cluster rolling mill to transfer the titanium element back and forth between the reels to move the element between pressure rolls of the mill a plurality of times and under forward and back tension in air at room temperature to initially reduce the element thickness enough to permit the element to be coiled on the reels and then to partially coil the element on the reels to further reduce element thickness. Iron aluminide material is interleaved with a loose coil of the element and the element is heated in a protective atmosphere to stress relieve and partially recrystallize the element material between the reductions in thickness.

Abstract: A method for producing hollow titanium alloy articles which comprises casting a plurality of segments which can be joined to provide a unitary, hollow article, treating the cast segments in such manner as to refine the microstructure of the segments and superplastic forming/diffusion bonding the segments into the desired hollow article.

Abstract: A first method for producing articles of gamma titanium alumide alloy having improved properties comprises the steps of: (a) shaping the article at a temperature between the titanium-aluminum eutectoid temperature of the alloy and the alpha-transus temperature of the alloy, and (b) aging the thus-shaped article at a temperature between about 750.degree. and 1050.degree. C. for about 4 to 150 hours. Shaping is preferably carried out at a temperature about 0.degree. to 50.degree. C. below the alpha-transus temperature.A second method for producing articles of gamma titanium aluminide alloy having improved properties comprises the steps of: (a) shaping the article at a temperature in the approximate range of about 130.degree. C. below the titanium-aluminum eutectoid temperature of the alloy to about 20.degree. C.

Abstract: Hydrogen storage alloy includes porous base hydrogen storage alloy and Mg which is fused, conjugated with the base hydrogen storage alloy and diffused in the base hydrogen storage alloy.

Abstract: An alpha-beta titanium-base alloy having a good combination of strength and ductility with a relatively low cost composition. The composition, in percent by weight, is 5.5 to 6.5 aluminum, 1.5 to 2.2 iron, 0.07 to 0.13 silicon and balance titanium. The alloy may have oxygen restricted in an amount up to 0.25%. The alloy may be hot-worked solely at a temperature above the beta transus temperature of the alloy to result in low.TM.cost processing with improved product yields. The hot-working may include forging, which may be conducted at a temperature of 25.degree. to 450.degree. F. above the beta transus temperature of the alloy. The hot-working may also include hot-rolling, which also may be conducted at a temperature of 25.degree. to 450.degree. F. above the beta transus temperature of the alloy.

Abstract: A process for working .beta. titanium alloy comprises the steps of first elongating the alloy at a temperature not higher than a .beta. transus temperature and at a working ration of 30% or more. Next, conducting a subsequent aging treatment. Then, elongating the alloy at a temperature not higher than the aging treatment temperature and at a working ratio of 70% or more when combined with that in the first step for elongating. Then a recrystallization treatment is carried out at a treating temperature not higher than the .beta. transus temperature or isothermal working is carried out within a temperature range of the .beta. transus temperature minus 200.degree. C. to the .beta. transus.

Abstract: A process for manufacturing rolled articles of titanium material comprising steps of contacting heated titanium material with fluorine- or fluoride-containing gas to form a fluoride layer on the surface of the titanium material, removing the fluoride layer formed thereon just before rolling and then rolling the titanium material to give a rolled article. With this structure, passive coat layers, such as the oxide layer on the surface of the titanium material is changed to a fluoride layer. The fluoride layer protects the surface of the titanium material. Therefore even if there is space of time between formation and removal of the fluoride layer, the fluoride layer formed on the surface of the titanium material protects the same surface in a favorable condition, which results in preventing re-formation of an oxide layer on the titanium material surface.

Abstract: Titanium niobium aluminide alloys having improved room temperature ductility and fracture toughness are comprised of, in atomic percent, about 18 to 30 percent aluminum, about 18 to 34 percent niobium, about 0.25 to 7 percent vanadium, and the balance substantially titanium.

Abstract: An alloy comprising titanium, aluminum and niobium has a heterophase micrructure of an orthorhombic, Ti.sub.2 AlNb, phase and an omega-type, B8.sub.2, phase. An alloy is annealed to form the heterophase alloy with the orthorhombic and omega-type phases in thermodynamic equilibrium, and then cooled.

Abstract: Disclosed is a process of surface hardening of Ti-6A1-4V alloy that can be performed by electrolytic charging in an acid solution, subsequent solution treatment, followed by dehydrogenation to obtain an equiaxed alpha grain in transformed beta matrix. Surface hardnesses of the processed specimens are better than that of the mill-annealed specimen. The depth of hardened layer depends on the charging time.

Abstract: A biocompatible titanium alloy with low elastic modulus containing titanium, about 10-20 wt. % or 35 to about 50 wt. % niobium and up to 20 wt. % zirconium useful for fabricating of orthopedic implants. This invention relates generally to high strength, biocompatible alloys suitable for use as a material for a medical prosthetic implant and, in particular, a titanium alloy which has a relatively low modulus of elasticity (e.g. closer to that of bone than other typically-used metal alloys) and does not include any elements which have been shown or suggested as having short term or long term potential adverse effect from a standpoint or biocompatibility.

Abstract: There is disclosed an engine valve of titanium alloy having a stem portion made of a cold-worked titanium alloy containing 2% to 4% by weight of aluminum, 1.5% to 3.5% by weight of vanadium and balance titanium. The engine valve suitable for use as an intake valve has a head portion made of a cast titanium alloy containing 2% to 7% by weight of aluminum, 3% to 20% by weight of vanadium and balance titanium. Moreover, an exhaust engine valve has a head portion made of a cast titanium alloy containing 5% to 10% by weight of aluminum and balance titanium.

Abstract: A method of hardening the surface of titanium and its alloys, and other structural metals which form hard carbides, by treating the surface thereof with a moving, discontinuous carbon arc.The metal surface to be hardened, and a carbon electrode are made opposite poles of an electric current source, and moved and/or rotated with respect to each other so that a multiplicity of discontinuous electric arcs are produced between the carbon electrode and the metal surface.Carbon particles transfer through the arc and alloy within craters of the instantly liquified and chilled substrate, producing a surface layer which, in the case of titanium, is hard and tough and adherent enough to form the working surface of abrasive cutting tools.The process improves the appearance and durability of consumer items and reduces friction and wear on machine parts.

Abstract: A wear-resistant titanium alloy containing titanium carbides which are crystallized and/or precipitated and are dispersed in the .beta.-phase matrix is disclosed. The alloy may further comprise .alpha.-phase and/or additional hard particles dispersed in the .beta.-phase matrix.

Abstract: A heat treatment method for producing moderate .alpha. grain size (50-250 .mu.m) fully lamellar, microstructures in thin cross section near-.gamma. titanium aluminide alloy products is described, wherein a wrought, fine y grain starting microstructure is heated at a temperature high in the two-phase .alpha.+.gamma. phase field and 30-60.degree. C. below the .alpha. transus temperature to produce a structure of small equiaxed .alpha. grains (about 25 .mu.m dim) and fine .gamma. phase grains, which is then briefly heated to a temperature in the single-phase .alpha. field in order to complete dissolution of remnant .gamma. grains and to minimize growth of .alpha. grains. The material is then cooled to transform the microstructure to fully lamellar .alpha..sub.2 +.gamma..