Abstract: A non-destructive measurement method for determining residual stress proximate an intermediate layer in a multilayer thermal barrier coating system by directing a laser beam through an outer ceramic thermal insulating layer with the laser beam illuminating a ceramic-bearing intermediate layer in a manner to cause species present in the intermediate layer to fluoresce, measuring the frequency of the light or photons emitted by the fluroescing species, and comparing the measured frequency shift of the intermediate ceramic layer to the frequency shift determined on like ceramic material under controlled stress states to determine a representation of relative residual stress in the measured coating. The invention can be used to assess integrity or quality control of as-manufactured TBC coatings or to assess remaining coating service life of engine-run TBC coated components during an inspection or repair procedure.

Abstract: A method of removing ceramic material, such as for example a ceramic core, from a metallic cast or other component involves contacting the metallic cast component and a caustic ceramic leaching medium at elevated temperature for a time effective to substantially remove the ceramic material from the component and providing an oxygen getter in the caustic ceramic leaching medium in an amount effective to avoid deleterious surface corrosion of the component while the ceramic material is being removed therefrom.

Abstract: A method of improving the stress corrosion resistance of an alloy comprising heating a martensitic stainless steel to a molten state and incorporating into said molten steel from 0.5 to 2.0 weight percent of an additive selected from the group consisting of platinum, palladium or a mixture thereof.

Abstract: A method is disclosed for scribing chemical milling maskant applied to a metal substrate by impinging a laser beam on the maskant and controlling the beam to penetrate through the maskant substantially without damaging the underlying metal. In carrying out the process, a metal part such as aluminum, titanium or their alloys is coated with an organic polymer maskant having absorption to a laser beam, a predetermined pattern is scribed in the maskant by impinging a laser beam, e.g. a Nd:YAG (neodymium doped yttrium aluminum garnet) laser, under controlled conditions to scribe a predetermined pattern in the maskant and substantially without damaging the underlying metal, removing the maskant portion within the circumscribed area of the pattern to expose the underlying metal and leaving the remaining maskant portion adhered to the substrate, immersing the metal substrate in a chemical milling solution, e.g.

Abstract: A composite is produced by placing a reinforcement between foils of a superplastic metal alloy to provide stack. The stack is then heated to a temperature at which the metal alloy exhibits its superplastic properties, and pressure is applied to the heated stack. This causes the foils to flow around the reinforcement and diffusion bond together in the solid state. A structural composite is thus formed comprising a reinforcement dispersed throughout a matrix of superplastic metal alloy.

Abstract: A method is provided to impart a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is overaged to form coarse precipitates, and then plastically deformed at least 40%. Deformation is accomplished at a temperature and at a rate which are sufficient to retain strain energy in the alloy at the end of the deformation step. The alloy is subsequently heated at a rate of at least 0.02.degree. F..multidot.s.sup.-1 to a recrystallization temperature to form a new fine grain structure.

Abstract: A titanium base alloy with improved superplastic properties is provided. The alloy has 6% Al and from 1.5 to 2.5% of a beta-stabilizing element which has high diffusivity in titanium, namely Co, Fe, Cr, or Ni. In a preferred embodiment, the alloy is a Ti-6Al-4V type alloy modified by the addition of about 2% Fe.

Abstract: A method and apparatus are provided for automatically controling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship.

Abstract: A predominately .alpha.-phase titanium base alloy having good high temperature creep strength. The alloy has about 8% aluminum to promote a strengthening .alpha..sub.2 precipitate, and about 5% columbium to ductilize the .alpha..sub.2 precipitate. Additionally, the alloy has about 5% zirconium, up to 0.5% silicon, up to 2% tin, and up to about 1.5% molybdenum.

Abstract: A method is provided for imparting a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is first heated to a solid solution temperature to dissolve the precipitating constituents in the alloy. The alloy is then cooled, preferably by water quenching, to below the solution temperature and then overaged to form precipitates by heating it above the precipitation hardening temperature for the alloy but below its solution treating temperature. Strain energy is introduced into the alloy by plastically deforming it in a temperature range of 380.degree. F. to 450.degree. F. to reduce its cross-sectional area a total of 40% minimum, at least 25% of the reduction in area being accomplished in a single continuous deformation operation. The alloy is then subsequently held at a recrystallization temperature so that new grains are nucleated by the overaged precipitates and the development of these grains results in a fine grain structure.

Abstract: A method and apparatus are provided for automatically controlling the strain rate during superplastic forming of a blank of material into a part. The method and apparatus produce a part in a minimum time by deforming the material in its optimum superplastic conditions. A relationship is determined between time and the pressure required to form the blank against the configured surface of a die at a strain rate which causes the blank to flow superplastically. The blank is positioned in the die and held at a temperature at which the material exhibits superplasticity. Pressure is automatically applied across the thickness of the blank in accordance with the previously determined relationship between time and pressure until the part is formed. The apparatus comprises conduits connected to a die and to a high pressure gas. Valves in the conduits regulate the pressure applied to the blank. A controller receives command signals from a programmer which is programmed with the desired time vs pressure relationship.

Abstract: A method is provided for imparting a fine grain structure to aluminum alloys which have precipitating constituents. The alloy is first heated to a solid solution temperature to dissolve the precipitating constituents in the alloy. The alloy is then cooled, preferably by water quenching, to below the solution temperature and then overaged to form precipitates by heating it above the precipitation hardening temperature for the alloy but below its solution treating temperature. Strain energy is introduced into the alloy by plastically deforming it at or below the overaging temperature used. The alloy is then subsequently held at a recrystallization temperature so that the new grains are nucleated by the overaged precipitates and the development of these grains results in a fine grain structure.