Abstract: A continuous curve arch shape cross section corrugated injection molded thermoplastic chamber is provided and includes a body having a multiplicity of peak and valley corrugations running along the curve of the arch shape, wherein the multiplicity includes opposing sidewalls, each having a foot, opposing chamber ends connected to the body, the ends shaped to form joints with the ends of like chambers, a multiplicity of sprues, within spaced apart valleys, at elevations intermediate the foot and apex of the chamber, wherein each sprue has a first runner running upwardly alone the valley in direction of the apex, and a second runner running downwardly along the valley toward the foot, a base runner connected to the bottom of the second runner, running lengthwise along the foot of the chamber; and at least one third runner connected to the base runner and running upwardly along a peak adjacent the valley.

Abstract: Two identical arch shape cross section chambers are joined together so that a dome shape part of one end of the chamber is overlapped by the opposing plain end of the second chamber. Thus, one chamber may pivot in the horizontal plane, for adjustment during installation. A latch at the top of the joint between the chamber pair inhibits vertical motion and separation of the overlapping chamber, while permitting horizontal plane pivoting. A latch comprises a tang which cantilevers outwardly from the top of the dome end, to engage a catch which is a flared portion of lip on the overlapping plain end.

Abstract: Backers for electron beam hole drilling contain glass particulates with a binder. For nickel base alloys, the glass particulates have at least 7 weight percent low temperature constituent, with a melting point less than 1500.degree. C., and a balance of high temperature constituent having a vaporization point of greater than 2000.degree. C. at 1 atmosphere. Softening points of the glasses exceed 700.degree. C. and preferably are in the range 800.degree.-1000.degree. C. A useful glass will have a viscosity of at least about 10 Pa.multidot.s when it melts. More preferred silicate glasses contain by weight percent at least 8Al.sub.2 O.sub.3, 9CaO, and 3B.sub.2 O.sub.3.

Abstract: Disclosed is an electron beam drilling system wherein an optical fiber link is used to prevent deviant drilling. The position of fixtures within a vacuum chamber is monitored by alignable fiber segments. The junctions of the segments form couples which transmit light from a source to detectors when the fixtures are properly positioned. The alignable fiber segments are mounted on and under the fixtures in a manner which integrally provides protection of the junctions from metal spatter. The light source and detectors are mounted external to the chamber; seals are provided where the fiber segments pass through the chamber wall. The detectors signal a control system to only allow beam output when the fixtures and parts thereon are properly positioned.

Abstract: Disclosed is an improved abrasive material particularly useful as a dispersoid in metal matrices to provide articles of use having superior abrasive properties, especially at elevated temperatures. The improved abrasive material typically comprises silicon carbide particulate, the individual particles of which have a predominantly alumina coating thereon to inhibit dissolution of the particles in the metal matrix at high temperatures. The invention finds special application in abrasive blade tips for service in gas turbine engines, the tips comprising a nickel base or cobalt base superalloy having the alumina coated silicon carbide particles dispersed therein.

Abstract: Disclosed is an interlayer for brazing and diffusion bonding, having a portion as a continuous stratum with an amorphous structure. The amorphous stratum of the interlayer, being ductile, imparts structural integrity to the otherwise brittle alloy composition. Thus, forming and shaping of the interlayer to faying surfaces are improved. In the joining process, the interlayer melts, and on solidifying by cooling or interdiffusion of elements, is converted to a crystalline solid metallurgically bonded to the workpiece. Preferred are flat ribbons with a continuous amorphous surface stratum comprising at least 30 volume percent, and up to 100 percent, of the interlayer.

Abstract: A method for electrolytically etching metals. Nickel superalloys are etched with uniform grooves using a 10 volume percent HCl aqueous solution and periodically reversed current. An aperture containing shield is interposed between an upward facing workpiece and an electrode. The shield is adapted to divert gases evolved at the workpiece from passage to electrode. Controlled roughness in an etched surface is produced by varying electrolyte temperature. Preferred smooth finish is obtained at 7.degree. C.

Abstract: An article with an improved MCrAlY coating is disclosed wherein a plasma sprayed MCrAlY coating is provided with a metallic envelope and then hot isostatically pressed to densify the coating and interdiffuse the envelope. Thus, the substrate is provided with a coating which in its bulk is the densified plasma coating with an outer surface zone which is enriched in a metal which enhances the oxidation-corrosion protective properties of the coating. Preferred coatings have a standard CoCrAlY bulk with a metal-enriched surface zone of about 0.02 mm depth. When aluminum is added the surface zone is comprised by weight percent of about 60 Co, 20 Cr and 22 Al. With chromium the surface zone is about 50 Co, 43 Cr and 8.5 Al.

Abstract: Improved refractories for resisting attack of molten titanium aluminum and similar metals are provided by the inclusion of sulfur. Metal, oxygen, and sulfur combinations, wherein sulfur is present at from 10 to 60 atomic percent, are particularly useful.Disclosed is a material having the atomic formula M.sub.a S.sub.b O.sub.c where O is oxygen, S is sulfur, and M is at least one metal selected from the scandium subgroup of the periodic table transition metals (scandium, yttrium and the rare earths) and aluminum. In an alternate material, M is comprised of at least two elements, the first selected as above and the second selected from the alkaline earth metal group. A preferred material is formed by mixing and firing CaS and Y.sub.2 O.sub.3 in proportions which results in (Ca+Y).sub.0.43 S.sub.0.14 O.sub.0.43.

Abstract: Disclosed is an electron beam hole drilling process in which the workpiece surface where the hole exits is covered with a backer comprising particulate bonded to itself and the exit surface by a binding agent. The backer enables a hole having substantial uniform symmetry along its length to be drilled and is particularly useful for hollow parts and contoured surfaces. Backers removable by liquifying, melting dissolution, leaching and the like, are particularly useful for inaccessible exit surfaces. In a preferred embodiment the backer is comprised of a nonmetallic particulate such as glass while the binder is a soluble silicate.

Abstract: An apparatus for electrolytically etching a precision groove pattern in a metal workpiece. A concave shaped shield having a small aperture contains the electrode. The shield diverts gases evolved at the upward facing workpiece away from the electrode while still allowing circulation of electrolyte about the electrode.

Abstract: The adherence and wear resistance of chromium alloy electroplates on titanium is improved by pretreating the substrate to form a chromium conversion coating, and post-treating the substrate at a temperature at about 700-820.degree. C. (1300-1500.degree. F.) for about 1-300 hours. The pretreatment is comprised of the formation of a chromium conversion coating from an acid chromate solution; a preferred solution is comprised of hydrofluoric acid, sodium chromate, and water. The post treatment causes diffusion sufficient to obtain a bond but avoids completely interdiffusing the chromium alloy electroplate, to preserve the wear resistance of the electroplate surface.

Abstract: Disclosed is apparatus and method for electrochemically finishing the edges of airfoils and other thin edged objects. When the edge on an airfoil varies in thickness along its length, a tapered electrode is provided which has both a decreased diameter and increased spacing distance, providing a means for obtaining an edge with a radius proportioned to the thickness. Generally, in the system having an electrode with a unit surface area A, and with an electrode-workpiece surface spacing distance S, both A and S are changed so that the ratio A/S is lowered for electrode portions proximate to edge portions having lowered thickness.

Abstract: There are described MCrAlY type coating alloys having improved hot corrosion resistance, especially to sulfur and/or halide bearing compounds. In particular, improved hot corrosion resistance is achieved by the inclusion of about 1 to 12 weight percent titanium in the MCrAlY alloy composition.

Abstract: An interlayer for transient liquid phase diffusion bonding is provided by depositing a metallic coating on at least one of the superalloy surfaces to be bonded and boriding a portion of the metallic coating to form a working coating having an overall composition resembling that of an interlayer alloy and an overall melting temperature less than that of the superalloys. When the superalloy surfaces are placed in contact and heated to above said melting temperature, the partially borided metallic coating functions as an interlayer alloy to effect bonding.

Abstract: An improved method of directional solidification is provided by varying the rate of withdrawal of a casting from the hot zone of a solidification furnace according to the sense of change of the perimeter to area ratio of the casting. The rates are varied to achieve desired microstructure and resultant properties in the casting. Also, the rate of withdrawal is varied according to controlled and predetermined relationships to cause the solidification interface to move through a transition section connecting sections of differing perimeter to area ratios in a manner which produces a desired microstructure in a first, transition, and second sections.

Abstract: Nonmetallic inclusions and like contaminants are removed from a metal charge by melting the charge to form a molten pool on which the inclusion contaminants float and directing an electron beam onto a preselected first portion of the pool surface, said selective beam impingement causing the floating contaminants to segregate to other portion not subjected to beam impingement. Removal of molten metal from the impinged surface portion while the inclusion contaminants are confined elsewhere on the pool surface provides a clean molten metal product. Apparatus for use with the process is also disclosed. The invention finds special application in the master melting or remelting of metals and alloys for conversion to ingot shapes or high purity molten metal for powder making, investment casting, forging and the like.

Abstract: Disclosed is a preformed ceramic base useful in firing an open-ended ceramic shell mold having a mold base prior to metal casting. The ceramic firing base includes a working surface having a majority of flat surface portions for supporting the mold base during firing and one or more groove-like surface portions which define gas circulation passages from the outside atmosphere into the open mold bottom when the mold base is placed in supported relation on the flat surface portions. The ceramic firing base thereby enables firing of a green shell mold while maintaining mold base flatness and circulation of furnace gas into the mold cavity to minimize mold hot spots. Also disclosed is a preformed ceramic firing cap to be used in conjunction with the ceramic firing base, the firing cap being adapted to cover the open top end of the shell mold to prevent foreign particulate from entering the mold.

Abstract: Disclosed is an electron beam drilling process in which the workpiece surface first penetrated by the beam is coated with a stop-off material having the required high temperature resistance for preventing formation of burrs around the perimeter of the hole from hot molten spatter which is ejected from the entrance to the hole during the drilling operation. A preferred stop-off material is a substantially continuous layer of boron nitride on the first penetrated surface of the workpiece.

Abstract: A vacuum vapor deposition apparatus having a plurality of electron beam sources spaced about the periphery of the molten alloy pool is provided. The electron beam sources have associated therewith focusing and deflection devices for directing each electron beam onto the pool surface opposite its source in the form of an inwardly curved impingement band. These create an approximate toroidal shaped heating pattern to the pool, this pattern providing uniform temperature and minimizing severe thermal gradients therein. As a result, variations in the chemistry of the vapor emanating from the pool are substantially reduced, thereby providing improved control of the as-deposited coating composition. The apparatus is especially useful in vaporizing alloys of complex chemistry, such as coating alloys in the MCrAlY family.