Abstract: This invention provides alloys having optimum high and low temperature mechanical properties for use of both the high and low pressure ends of turbine rotors in a single row power generation turbine with a service temperature profile from about 75.degree.-1200.degree. F. (24.degree.-649.degree. C.). The alloys include about 8.00-9.5 wt. % Cr and about 0.85-1.05 wt. % Mo and are heat treated at 1225.degree.-1350.degree. F. (663.degree.-732.degree. C.) for at least about one hour. The alloys and the components manufactured from these alloys preferably include a room temperature 0.2% yield strength of about 80-110 ksi (551-758 MPa).

Abstract: A separate inter-blade platform for a bladed rotor disk of a turbo-machine comprises a first part in the form of a four-sided frame of generally trapezoidal shape and made of a laminated material, the frame having smaller and larger ends for location on the upstream and downstream sides respectively of the rotor disk, and two lateral sides interconnecting said ends for location between successive blades of the rotor, and a second part made of a relatively flexible and self-adhesive material of the polyurethane type attached to the first part, the second part defining a plate capping the frame over the greater part of its two lateral sides and leaving the smaller and larger end portions free, a portion enclosing the two lateral sides of the frame in line with the plate, and a plurality of evenly spaced, transverse reinforcing ribs which are integral with said enclosing portion and the underside of the plate.

Abstract: A steam turbine blade is provided having a trailing edge portion formed from an erosion resistant material deposited on the blade airfoil by a friction surfacing method. According to the method, a rotating consumable rod of erosion resistant material is placed in contact under axial load against a bonding surface formed on the airfoil, thereby causing a portion of the rod adjacent the bonding surface to be plasticized. The rod then traverses the surface linearly leaving in its wake a layer of erosion resistant material bonded to the airfoil by a high quality metallurgical bond. The layer is then ground to form the smooth contour desired for the trailing edge.

Abstract: A metallic reinforced shim is attached to the dovetail of turbine or compressor blades. The shim reduces frictionally induced wear damage to the rotor. In one form, a single ply shim reinforced with a metallic doubler has an anti-fretting layer deposited on the shim face contacting the dovetail slot pressure face, and a doubler layer fastened to the anti-fretting layer in the non-contacting regions to prevent slippage of the shim on the blade. In another form, a multi-layer shim has two layers interposed between the blade dovetail and the disk dovetail slot, with the layers treated so that they do not readily slip relative to the titanium pieces, but do slip relative to each other. The shim is also reinforced with a metallic doubler. Fretting is confined to the consumable shim, and therefore the disk dovetail slot and the mating blade dovetails are not subject to surface degradation with corresponding reduction in fatigue capability.

Abstract: A method for improving the capability of a body to withstand stress during rotation of the body by inducing at a selected location in the body a residual compressive stress which opposes the steady tensile stress produced by rotation. The method comprises rotating the body at a succession of increasing peak speeds in excess of the design speed to induce tolerable yielding and residual compressive stress at each location experiencing higher steady tensile stress than the selected location. The succession proceeds from the location experiencing the highest steady tensile stress above that at the selected location to the location experiencing the lowest steady tensile stress above that at the selected location. Then the body is rotated to a still higher peak speed to induce tolerable yielding and residual compressive stress at the selected location.

Abstract: A marine propeller including an inner hub to receive a driving connection to the engine and an outer hub is spaced outwardly from the inner hub to provide a passage therebetween for the discharge of exhaust gas from the engine. A plurality of blades extend outwardly from the outer hub. A propeller is die cast from an aluminum alloy and as cast the outer surface hub is cylindrical in configuration. After casting the trailing end of the outer hub is swaged outwardly by a tapered tool to provide an outwardly flared trailing end, which assists gas flow and enhances performance of the engine.

Abstract: Ceramic turbine wheels are balanced to minimize rotational vibrations by bonding silica-based glass pads to the wheel. The pads are formed from a mixture of sodium silicate, water and a fine ceramic powder, preferably of a composition similar to the underlying ceramic turbine wheel. The weighted pads are machined, without damage to the underlying ceramic wheel, to achieve proper balance.

Abstract: A rotor and a method for the production thereof which incorporates the inently strong, highly damped, yet light weight characteristics of fiber reinforced plastic composites, Achieving with a minimal amount of added weight in the form of high density material a significant reduction in the vibratory response of the rotor due to hydrodynamic flow excitation, by selectively tailoring the mass distribution therein as by adding the high density material at selected locations of the rotor.

Abstract: An improved erosion resistant coating for a gas path component of a turbo machine which comprises the thermal spraying of a chromium carbide, such as Cr.sub.3 C.sub.2, and an age hardenable nickel base alloy, such as Inconel 718, onto the gas path component and then, preferably, heat treating the deposited coating to harden the coating.

Abstract: A bladed rotor having blades with blade shrouds includes a deformable protective coating applied to the blades to increase the damage tolerance of the blades during foreign object ingestion. The protective coating deforms upon impact between the shroud and airfoil of adjacent blades. The deformation absorbs impact energy and improves distribution of the impact load transferred between the blades.

Abstract: A lightweight propulsor blade (10) is constructed 10 of a hollow internal spar (30) and an exterior airfoil shell (20) which defines and encompasses a hollow interior cavity (26). The internal spar (30) is disposed within the cavity 26 and extends spanwisely from its tip portion to terminate in a spar root portion (40). The spar has at least forward and aft spanwisely extending, chordwisely spaced, hollow box-like cavities (52A, 52B), a leading edge shear web (53) projecting chordwisely forward from the forward cavity (52A), a trailing edge shear web (55) projecting chordwisely rearward from the aft cavity (52B), and an intermediate chordwise shear web (57) spanning the space between and interconnecting the forward and aft cavities (52A, 52B). An additional intermediate box-like cavity (52C) may be incorporated in the intermediate chordwise shear web (57) in spaced relationship between the forward and aft cavities (52A, 52B).

Abstract: Taught is an improved tip-shrouded blade and a method of manufacturing the same. In accordance with the present invention, the inventive blade comprises a blade including an airfoil having a residual compressive stress in areas thereof subject to high local stress.

Abstract: A NiAl nickel aluminide alloyed with yttrium, optionally gallium, and an element selected from the group consisting of chromium, molybdenum and combinations thereof, having improved room temperature ductility and plastic strain. NiAl nickel aluminide intermetallics alloyed with no more than about 5 atomic percent of additional elements have significantly improved room temperature ductility over conventional unalloyed beta phase nickel aluminides or beta phase nickel aluminides alloyed with higher percentages of additional elements. The NiAl nickel aluminide comprises, in atomic percent, at least 50% nickel, about 0.01% to about 0.25% yttrium, about 0 to about 0.15% gallium, about 0.05% to about 4% of an element selected from the group consisting of chromium, molybdenum and combinations thereof, and balance from about 40% to about 49.85% aluminum and trace impurities.

Abstract: This invention is directed to a high damping and damage tolerant flexible opeller assembly and a method for the production thereof. The high damping and damage tolerant flexible propeller has a unitary hub having an axis of rotation and adapted for mounting on a rotatable shaft, multiple spokes extending from the hub portion, each spoke at its tip portion being made of a high density material having the shape that conforms to that of the specific propeller, each spoke at its inner portion from the tip portion to the hub portion being made of multidimensional fibers, the inner portion of each spoke being made of a multidimensional fiber preform being impregnated with a highly viscoelastic matrix material.

Abstract: A single crystal turbine blade has a portion of its attachment section reinforced by a core containing a fine grained, polycrystalline alloy. The blade is prepared by casting a single crystal body with a cavity within the attachment section, and then filling the attachment section with the polycrystalline superalloy to form a composite structure. Filling is preferably accomplished by plasma spraying the cavity with the superalloy, and hot isostatically compacting the sprayed superalloy to minimize porosity. The composite structure is then heat treated to develop an optimized microstructure in the dual alloy attachment section. The resulting turbine blade has improved low cycle fatigue life of the composite attachment section.

Abstract: Two pieces of metal are bonded together at a surface by placing the two pieces into contact at the surface and forging the two pieces in a die which causes substantial displacement of the metal originally at the surface in a direction parallel to and outwardly from the edges of the surface. In this way, many of the defects which are potentially present at the original surface are displaced with moving metal away from the original contact between the two pieces of metal into sacrificial ribs and the remaining defects are exposed to significant strain. A portion of the displaced metal which contains many of the defects and which forms the sacrificial ribs is removed from the resulting bonded work piece as the sacrificial ribs are removed from the work piece. The result is a bond with superior properties and with a bond surface which can be located very precisely.

Abstract: An article of manufacture having at least a first and a second part, each part having different mechanical properties, compositions, microstructures or combinations thereof, being joined together using a forging process to yield a substantially defect-free joint region. The article in the form of a turbine disk is particularly suited for use in a gas turbine engine in which the hub or inner portion must be resistant to low cycle fatigue and have high strength, while the rim or outer portion must be resistant to stress rupture failure and creep failure.

Abstract: An apparatus and method for providing vanes with a surface texture of less than 10.times.10.sup.-6 inches rms. The method employs a fluent mass having a particulate size less than 1.5 inches and abrasive materials in a centrifugal barrel to achieve a surface texture between 11-27.times.10.sup.-6 inches rms. A refinement cut employs a finer abrasive and a cycle time of less than 30 minutes to provide a burnished surface texture of between 5-8.times.10.sup.-6 inches rms. A final coloring cycle, employing only a coloring compound, is employed to provide a highly reflective surface texture between approximately 4-7.times.10.sup.-6 inches rms.

Abstract: A method and apparatus for securing or attaching a rotor blade with a turbine rotor cavity by disposing an expanding material between the blade root and the cavity walls. The expanding material comprises a naturally occurring mineral which expands to a great degree when exposed to elevated temperatures. The expanding material may be provided in the form of shims made directly from the expanding material or made from a composition of the expanding material and a binder such as a polymer or elastomer. Alternatively, the expanding material may be provided in the form of a liquid vehicle applied to surfaces of the cavity walls. The expanding material is located at specific positions within the cavity to urge certain surfaces of the blade root against certain surfaces of the cavity walls. In this manner, the blade can be forced into a tight fit and an aligned position, with respect to the rotor, upon expansion of the expanding material.

Abstract: A composite rotor blade comprising an outboard portion defining an airfoil surface, an inboard portion defining an end tang having a mounting section and an extension lug section. The mounting section of the end tang having at least one mounting aperture with an axis parallel to the chordline of the airfoil for mounting of the blade, and the extension lug section having at least one extension lug extending inboard of the mounting aperture to provide a lever surface for interaction with suitable mounting mechanisms.

Abstract: A radial inflow rotor for a gas turbine engine has a dual structure for improving the low cycle fatigue life of the saddle region. The interior core or hub of the rotor is a high strength polycrystalline alloy while a series of outer blade segments is individually cast as single crystals and bonded so that their low modulus (100) crystallographic axis is aligned substantially tangential to the rotor's circumference at the saddle.

Abstract: A propeller blade spar/foam subassembly is manufactured by disposing a lamination of prepreg within a mold, closing the mold about a spar and injecting foam into mold cavities formed at the lead edge and the trailing edge of the spar.

Abstract: A water turbine runner has a plurality of vanes, each made of a rolled steel plates which contains, by weight, 0.01 to 0.10% of C, 0.10 to 1.0% of Si, 0.10 to 2% of Mn, 2 to 7% of Ni, 10 to 15% of Cr and 0.10 to 4% of Mo, 71.9 to 87.7% of Fe, and which has a metallic structure mixture containing, by volume, martensite and 10 to 35% of residual austenite. Each of the vanes is made of a plurality of plate pieces, cut out from the rolled steel plate, press-formed in a shape of a part of the vane and joined by welding into the complete vane.

Abstract: Thermomechanical fatigue failure in components in high performance gas turbine engines is diminished by providing the component with an overlay of a metallic coating and a strain isolating layer located between the surface of the component and the metallic coating overlay.

Abstract: A water turbine used in river water which is comparatively rich in soil and sand particles. In order to improve the resistance to erosion due to cavitation, as well as erosion caused by mechanical action of the soil and sand particles, a water contactable portion of the water turbine, in particular a portion of each moving blade which tends to be eroded is formed of a stainless steel containing 0.07 to 0.2 wt % of C, not more than 2 wt % of Si, 7 to 15 wt % of Mn, 1 to 7 wt % of Ni, 10 to 25 wt % of Cr, 0.1 to 3 wt % of W, and the balance substantially Fe and inevitably accompanying impurities.

Abstract: A heat resistant steel of the present invention contains 0.05 to 0.2 wt. % of C, less than 0.5 wt. % of Si, less than 0.6 wt. % of Mn, 8 to 13 wt. % of Cr, 1.5 to 3 wt. % of Mo, 2 to 3 wt. % of Ni, 0.05 to 0.3 wt. % of V, 0.02 to 0.2 wt. % in total of either or both of Nb and Ta, 0.02 to 0.1 wt. % of N and the balance substantially Fe. Since a gas turbine of the present invention is constituted by members, such as discs, blades, shafts and so forth, made of alloys of this kind, the gas turbine has a structure in which it is possible to achieve a high level of creep rupture strength and Charpy impact value.

Abstract: A gas turbine includes a turbine stubshaft, a plurality of turbine disks coupled to the shaft by turbine stacking bolts with spacers interposed therebetween, turbing moving blades planted in each of the disks, a shroud provided with a sliding surface in a spaced-apart relation to the tips of the moving blades, a distant piece connected to the disks by the bolts, a plurality of compressor disks coupled to the distant piece by compressor stacking bolts, compressor blades planted in each of the compressor disks, and a compressor stubshaft formed integrally with the compressor disk located at the first stage. At least a sliding portion of the shroud is made of a heat-resistant cast alloy having in turn a chilled layer and columnar grains in a direction oriented from the sliding surface thereof toward the interior thereof.

Abstract: A composite propeller blade construction has fiber strands extending predominantly in a radial direction and looping around mounting hardware connecting a blade root to a rotor hub. The mounting hardware includes at least one bolt secured to the rotor hub or a shackle member secured to the hub by a mounting bolt and holding a tying bolt so that fiber strand loops forming the blade body loop around the shackle member and around free ends of the tying bolt. The radially extending fiber strands take up centrifugal forces and are enclosed by a jacket, the radially inner end of which is formed as mounting flanges screwed to a respective rim of the hub. The arrangement of the fiber loops is especially suitable for a fiber composite lightweight construction wherein the fibers form redundant load take-up paths and provide an advantageous centrifugal force and moment introduction into the structure.

Abstract: A rotating or moving metal component such as a blade for a gas turbine engine is made from a composite bar of titanium alloy with the sides of the bar having a surface layer of e.g. nickel which is less likely to ignite in particle form or by frictional heating when present in oxygen or air. After the surface layer has been bonded to the titanium alloy it is then parted to provide sections which extend perpendicularly to the plane of the surface layers. Each parted section may then be machined into a blade with the nickel portion forming the tip of the blade. Alternatively, each parted section may itself form the blade tip by attachment on its titanium alloy side to a blade stem.

Abstract: System for repairing worn surfaces of steam turbine components and especially high pressure turbine rotors, are disclosed. These systems include depositing a first layer of weld metal on a worn surface of the component, whereby a heat-affected zone is created. A second layer of weld metal is then deposited over the first layer using a greater amount of heat to temper at least a portion of the heat-affected zone produced by the first layer. The preferred embodiments include the use of gas tungsten arc welding for providing fine-grain size and more creep resistance, especially in the weld and heat-affected zone. The resulting build-up can be machined, for example into a blade fastening to produce a component having properties equal to or better than the base-metal alloy. The invention also provides a longer lasting turbine system, including rotors which have serrated steeples that are more resistant to failure.

Abstract: A single crystal turbine blade has a portion of its attachment section layered with a fine grained, poly-crystalline alloy. The blade is prepared by casting a single crystal body with an undersized attachment section, and then layering the attachment section with the poly-crystalline superalloy to form a composite structure. Layering is preferably accomplished by plasma spraying the body with the superalloy, and hot isostatically compacting the sprayed superalloy to minimize porosity. The composite structure is then heat treated to develop an optimized microstructure in the dual alloy attachment section. The polycrystalline material in the attachment section may be machined to a firtree shape for mounting in a turbine wheel. The resulting turbine blade has improved life resulting from reduced low cycle, low temperature fatigue susceptibility of, and crack growth in, the composite attachment section.

Abstract: A dual alloy gas turbine rotor is heat treated by HIP bonding a cast superalloy blade ring to a consolidated, powdered-metal hub. After bonding, the assembly is solution treated and aged at certain specific temperatures so as to optimize the mechanical properties of the dual alloy assembly for use in a high performance gas turbine engine.

Abstract: A rotary gas seal in which a first member, e.g., a tip, cooperates with a second member to inhibit gas flow therebetween, the improvement wherein, the tip is provided with a ceramic or metallic coating bonded thereto, the surface of the coating having a plurality of laser-formed depressions and providing a wear-resistant, cutting surface capable of cutting into the second member. Also, a turbine or compressor blade having a tip surface adapted to cooperate with a sealing surface to form a seal between the blade and the sealing surface and a ceramic or metallic carbide coating bonded to said tip surface, the coating having a plurality of laser-formed depressions and providing a wear-resistant, cutting surface capable of cutting into the sealing surface.

Abstract: A composite gas turbine blade consists of an airfoil (1) in an oxide-dispersion-hardened nickel-based superalloy, in the condition of longitudinally directed coarse columnar crystals, and a shroud plate (6) or a shroud and a root (7), the latter items in a non-dispersion-hardened nickel-based superalloy (cast alloy). The gas turbine blade is manufactured by casting in and casting round, using the non-dispersion-hardened superalloy mentioned, the tip end (2) and root end (3)--provided with depressions (4) and/or protrusions (5)--of the airfoil (1), after preheating the latter to a temperature of between 50.degree. and 300.degree. C. below the solidus temperature of the lowest melting phase of the airfoil material. The casting temperature for this should be a maximum of 100.degree. C. above the liquidus temperature of the highest melting phase of this non-dispersion-hardened alloy. Any melting onto the airfoil (1) and any metallurgical connection is to be avoided.

Abstract: A composite member includes circumferentially extending ceramic fibers in a metallic matrix. A rotor member integrally includes such a ceramic fiber/metal matrix composite member to reinforce a homogeneous remainder portion of the rotor member with respect to centrifugally induced stresses. Method of making are included in the disclosure.

Abstract: A composite compressor wheel for turbochargers and the like comprises a cast shell having aerodynamically contoured centrifugal impeller blades and a hub section defining a generally conical recess into which a hub insert of noncast material resistant to stress failure is secured as by inertia welding. In use of the composite wheel, the hub insert substantially occupies high stress regions within the wheel to improve wheel fatigue life.

Abstract: A heat resistant steel of the present invention contains 0.05 to 0.2 wt. % of C, less than 0.5 wt. % of Si, less than 0.6 wt. % of Mn, 8 to 13 wt. % of Cr, 1.5 to 3 wt. % of Mo, 2 to 3 wt. % of Ni, 0.05 to 0.3 wt. % of V, 0.02 to 0.2 wt. % in total of either or both of Nb and Ta, 0.02 to 0.1 wt. % of N and the balance substantially Fe. Since a gas turbine of the present invention is constituted by members, such as discs, blades, shafts and so forth, made of alloys of this kind, the gas turbine has a structure in which it is possible to achieve a high level of creep rupture strength and Charpy impact value.

Abstract: A mixture of two powdered alloys of the M, Cr, Al type, M being Co and/or Ni, is disclosed, in one form, for use in providing an abradable surface of an article and is characterized by the substantial absence of B. The first alloy has substantially no Si and has a higher melting range than that of the second alloy. The second alloy has substantially no Y and consists essentially of, by weight, 8-12% Si, 1.5-4% Al, 10-30% Cr, with the balance M and incidiental impurities. The total mixture composition consists essentially of, by weight, 10-35% Cr, 4-10% Al, from a small but effective amount up to about 0.09% Y, 2-6% Si, with the balance M and incidental impurities.

Abstract: The pre-load device for a turbomachine rotor according to the invention has a shank formed of a superplastic material which is axially insertable in a shank bore formed between confronting notches formed on a rotor disk and a blade root portion. In one embodiment, the notches extend generally parallel to the longitudinal axis of rotation of the rotor disk. The shank defines an interior chamber in which is located a low-melting point material. An electrical resistance heating element is located in the low-melting point material and has means to be connected to an electrical source. The device also includes headed portions attached to each end of the shank, each of the headed portions bearing against axially facing surfaces of the rotor disk and the blade root so that, when the head means are attached, relative axial movement between the elements is prevented.

Abstract: A part and method for repairing a high velocity fluid flow machine part, for example a turbine blade comprises an insert which may be made from a piece of material the same as the turbine blade and prior to attachment to the blade has an edge region hardened by any suitable means, for example induction hardening, the insert then being secured to the blade by welding or brazing, the weld or braze material being of a relatively soft nature to provide a cushion between the insert and the blade so as to minimize the occurrence of stress corrosion cracking.

Abstract: The portion of the blade (1) to be coated has pure vanadium powder deposited thereon and the temperature of the powder is raised to a temperature which is slightly higher than the melting point of vanadium. Thereafter, a powder mixture is deposited on the vanadium layer, said powder comprising about one third by weight of titanium carbides, titanium nitrides, or titanium borides, which are bonded by a martensitic or austenomartensitic stainless steel. The powder is then raised to a temperature which is greater than its melting temperature and less than the melting temperature of vanadium. A titanium alloy blade it includes, on its periphery, a coating layer (5) which is at least 1 mm thick and which includes about one third by weight titanium carbides, or titanium nitrides, or titanium borides bonded by a martensitic or austenomartensitic stainless steel, said coating layer covering an under layer (6) of vanadium having a thickness lying between 0.5 mm and 1.5 mm.

Abstract: An improved structural strut for use in the fan section of a high bypass ratio gas turbine engine is described. The strut includes two I-beam shaped structural supports which are substantially perpendicular to each other, and extend along the major and minor axes of the strut, from the strut base to the strut tip. Face sheets, preferably made of composite material, are attached to both of the I-beam supports for acoustic damping effects.

Abstract: The worn tip of a turbine blade is restored by applying a metallurgically bonded wear resistant surface at the tip. The wear resistant surface is applied using a transferred plasma arc and powdered metal particles.

Abstract: A protective tip (5) for a titanium steam-turbine blade (1), comprises 28% to 40% TiC, 12% to 26% Cr+Co, 1% to 6% Mo, 3% to 8% Ni 0.3% to 1.5% Cu and a balance of Fe. The tip (5) is brazed to the blade (1) by interposing a copper-based strip (6) having a thickness lying between 7/100 mm and 15/100 mm therebetween, then raising the temperature of the blade (1) and its tip (5) to between 900.degree. C. and 950.degree. C. in a vacuum or inert atmosphere oven. This temperature is maintained for a period of between thirty minutes and seventy-five minutes, and the oven is allowed to cool to ambient temperature. Optimal brazing also serves to harden the tip (5) possesses very good resistance to abrasion by water droplets.

Abstract: A rotor member for a turbomachine includes a first portion formed of comparatively higher creep rupture strength material, and a second portion integrally joined to the first portion and formed of comparatively higher tensile strength material. The rotor defines a bore and is configured such that the operative environment thereof inflicts higher temperatures upon the first portion, and higher centrifugally-induced stresses upon the second portion. In order to improve the operating speed, burst margin, or both, of the rotor a plurality of circumferentially spaced and annularly arrayed cavities are provided within the rotor at the union of the two portions. The portions are intimately united by hot isostatic pressing (HIP) so that the rotor is of a single piece (monolithic) having portions of selected physical properties appropriate to the thermal/physical stresses imposed thereon, and defining voids which reduce the weight and bore stresses thereof.

Abstract: Applicants have identified and unexpected mechanism which contributes to solid particle erosion of the trailing edge of spaced apart aerodynamically shaped nozzle partitions in an axial fluid flow turbine. Particles entrained in the fluid flow pass through passages between nozzle partitions, strike rotating buckets and rebound upstream to impinge upon the suction side of the nozzle partitions in the trailing edge region. Accordingly, a nozzle partition includes a protection device disposed over at least a portion of the suction side of the nozzle partition, preferably from the trailing edge to the throat, for preventing solid particle erosion of the partition.

Abstract: A turbine rotor including a turbine vane wheel made of ceramics, a ceramic shaft formed integrally with the turbine wheel, and a metallic shaft bonded to the ceramic shaft. The hardness of a part of or the whole part of a compressor wheel-fitting shaft portion of the metallic shaft is made smaller than that of a portion of metallic shaft apart from the compressor wheel-fitting shaft, said portion being located on the turbine vane wheel side. Thereby, slackening between the compressor wheel and the fitting shaft is avoided. Methods of producing the turbine rotor are also disclosed.

Abstract: A molybdenum article is disclosed in which the substrate thereof has adherently bonded thereto a thermally self-healing plasma-sprayed coating consisting essentially of a composite of molybdenum and a refractory oxide material capable of reacting with molybdenum oxide under oxidizing conditions to form a substantially thermally stable refractory compound of molybdenum. The plasma-sprayed coating is formed of a plurality of interbonded plasma-sprayed layers of a composite of molybdenum/refractory oxide material produced from a particulate mixture thereof. The coating comprises a first layer of molybdenum plasma-sprayed bonded to the substrate of said molybdenum element and a second layer of plasma-sprayed mixture of particulate molybdenum/refractory oxide consisting essentially of predominantly molybdenum bonded to the first layer.

Abstract: Ceramic particles useful as abrasives in a metal matrix layer are described. The particles are coated with an oxide monolayer and a metal duplex layer. Preferably, the particles are silicon carbide; the oxide monolayer is aluminum oxide, and the metal duplex layer is a nickel-boron alloy over pure nickel.

Abstract: An improved propeller blade for use in an environment subjecting the blade to particulate impacts tending to erode the dynamic profile of the blade, and which is carried by a rotatable hub and extends radially therefrom, whereby the blade bends in cantilever fashion and twists axially of its length during operation. The blade may be either of the aluminum alloy type or of a resinous molded matrix type with reinforcing inclusions, and is cut away along its leading edge to accommodate therein a plurality of serially aligned but separate erosion resistant implants. The implants are formed of a silicon based ceramic material and are externally shaped to complement in profile continuity the prescribed efficient dynamic profile of the blade, and there is employed a novel system for restraining the implants against dislodgements during operation of the propeller.