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: A nondestructive evaluation method is described for ultrasonic evaluation and detection of features in polycrystalline materials, such as grain orientation (e.g. texturing) or grain boundary orientation. The method may, for example, be employed to detect diffusion bonds that contain undesirable planar grain boundary arrays. The method utilizes time of flight statistics gathered from reflections associated with incident ultrasonic signals directed into a plurality of locations within the material.

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: A method of heat treating Ti/Al-base alloys to improve tensile ductility and reduce the likelihood of in-service embrittlement is disclosed. The method comprises: selecting a Ti/Al-base alloy that contains a mixture of .alpha. and .alpha.2 phases, heat treating the alloy so as to form a controlled amount of .alpha.2 particles, and then cooling the alloy so as to primarily promote the growth of additional .alpha.2 on the previously formed particles, rather than the nucleation of new .alpha.2 particles. This method may be used with Ti/Al-base alloys that also comprise Sn, Ga and In as alloy constituents, and is believed to be useful for a number of Ti/Al-base engineering alloys. Alloys made by this method have been observed to maintain significant tensile ductility, even after aging at elevated temperatures under load (e.g. creep conditions).

Abstract: A method of making metal alloy articles having inclusions which are predetermined and controlled with respect to their size, shape, composition, crystal structure and location and orientation within the article is disclosed. In a preferred embodiment, the method of making is directed toward titanium alloy articles containing synthesized hard-alpha inclusions of titanium/nitrogen, titanium/oxygen and titanium/oxygen/nitrogen alloys.

Abstract: Titanium alloys containing aluminum, hafnium, tantalum, and silicon are found to have improved tensile strengths as well as ductility and oxidation resistance at temperatures up to and above 750.degree. C. without embrittlement.

Abstract: A method for improved atomization of molten metal having a melting point above 1000.degree. C. is taught. The atomization is carried out in close coupled atomizer. The melt to be atomized is supplied from a reservoir where it is heated to a temperature slightly above the melting point. The molten metal from the reservoir is guided to the atomization zone by a ceramic melt guide tube. The atomization is accomplished with the aid of a shallow draft atomizing nozzle. The melt in the melt guide tube is heated with the aid of an induction coil which is disposed thereabout and between the reservoir and the shallow draft gas nozzle.

Abstract: Enhanced crystallographic texture is developed in an alpha or alpha-beta titanium alloy having a dispersion of particles therein, by heating the alloy to essentially the all beta phase range and mechanically hot working the alloy in this range. The mechanical working is preferably accomplished by extrusion, rolling, or forging. The particles are stable during working, and prevent the formation of random texture in recrystallized beta phase grains at the working temperature. The particles are preferably oxides formed from rare earth elements such as erbium or yttrium, that are introduced into the alloy during manufacture. The alloys processed according to the invention are preferably prepared by powder metallurgy to achieve a uniform microstructure prior to working. A particularly suitable alpha-beta (but near alpha) titanium alloy contains aluminum, zirconium, hafnium, tin, columbium, molybdenum, tungsten, ruthenium, germanium, silicon, and erbium.

Abstract: A novel titanium base alloy having a micrograph with alpha plates oriented in three directions with respect to their parent beta grains, but with alpha plates so short that no basketweave pattern is evident. The alloy contains from 0.02 to 2.0 atomic percent boron; 6 to 30 atomic percent aluminum; 0 to 4 atomic percent tin; 0 to 4 atomic percent gallium; and may contain 0 to 6 atomic percent zirconium of hafnium or a mixture of the two; 0 to 12 atomic percent of at least one metal selected from the group consisting of vanadium, columbium, tantalum, chromium, molybdenum, rhenium, tungsten, ruthenium, and the platinum group metals; and from 0 to 2 atomic percent of at least one element selected from the group consisting of yttrium, carbon and the rare earth metals.

Abstract: There is provided by the present invention an alloy which is mechanically and chemically compatible with advanced nickel-base superalloys and nickel-base eutectic superalloys and which possesses excellent resistance to high temperature oxidation. The alloy of the invention is, therefore, particularly useful as a protective environmental coating for the external surfaces of hot-stage aircraft gas turbine engine components, e.g., rotating blades and stationary vanes, made from such advanced superalloys.

Abstract: A TiAl composition is prepared to have high strength and to have improved 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 by addition of tungsten and rapid solidification from the melt according to the approximate formula Ti.sub.50-48 Al.sub.48 W.sub.2-4.

Abstract: A TiAl composition is prepared to have high strength and to have improved 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 by addition of vanadium and rapid solidification from the melt according to the approximate formula Ti.sub.49 Al.sub.48 V.sub.3.

Abstract: A TiAl composition is prepared to have high strength and to have improved ductility by altering the atomic ratio of the titanium and aluminum to have what has been found to be highly desirable effective aluminum concentration by addition of tantalum according to the approximate formula Ti.sub.48 Al.sub.48 Ta.sub.4.

Abstract: A TiAl composition is prepared to have high strength and to have improved 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 by addition of chromium according to the approximate formula Ti.sub.52-50 Al.sub.46-48 Cr.sub.2.

Abstract: A TiAl composition is prepared to have high strength and to have improved ductility by altering the atomic ratio of the titanium and aluminum to have what has been found to be a higly desirable effective aluminum concentration by addition of boron according to the approximate compositions displayed in the shaded area of FIG. 10.

Abstract: A TiAl composition is prepared to have high strength and to have improved 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 by addition of silicon according to the approximate formula Ti.sub.54-57 Al.sub.39-41 Si.sub.4-5.

Abstract: A titanium aluminide base composition is provided which has increased tensile strength, ductility and rupture life due to the addition of tantalum coupled with optional additions of vanadium and columbium.

Abstract: Monocarbide reinforced nickel-base eutectic superalloys which are particularly characterized by improved resistance to the formation of surface nucleated carbides and are, therefore, especially suited for making unidirectionally solidified anisotropic metallic bodies in the form of vanes and rotating blades for aircraft gas turbine engines are provided.

Abstract: Monocarbide reinforced nickel-base eutectic superalloys which are substantially phase stable and have improved high temperature stress-rupture strength with improved resistance to the formation of surface nucleated carbides are provided. These superalloys are especially suited for making unidirectionally solidified anisotropic metallic bodies in the form of vanes and rotating blades for aircraft gas turbine engines.

Abstract: A directional solidification furnace is provided in which the susceptor is characterized by at least one substantially longitudinal slot to provide interference with eddy current motion and lower the furnace temperature in the slotted region and cause the highest temperature to be near the solid-liquid interface of a casting contained therein.