Rockwell International Corporation

Neil E Paton

C Howard Hamilton

Murray W Mahoney

John M Curnow

James Hall

Amit K Ghosh

Daniel S Gnanamuthu

Ralph J Moores

Richard F Vyhna

Jesse B Lumsden

Daniel P Dennies

Lillian W Ng

Cecil G Rhodes

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.

Method of improving stress corrosion resistance of alloys

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. an alkali solution, under controlled conditions to remove a predetermined thickness of the exposed metal from the substrate, and thereafter removing the remaining maskant portion from the substrate.

Non-contact scribing process for organic maskants on metals or alloys

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.

Structural metal matrix composite and method for making same

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.

Method of imparting a fine grain structure to aluminum alloys having

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.

Titanium base alloy for superplastic forming

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. The controller operates the valves and receives feedback information from a pressure transducer in the conduit to maintain the programmed time vs pressure relationship during the forming operation.

Apparatus for superplastic forming

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.

Titanium base alloy

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.

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. The controller operates the valves and receives feedback information from a pressure transducer in the conduit to maintain the programmed time vs pressure relationship during the forming operation.

Method for superplastic forming

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.

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Thousand Oaks, CA, United States of America

Neil E Paton