Abstract: A method for laser shock peening an article by simultaneously firing low energy first and second laser beams to form pairs of longitudinally spaced apart first and second laser shock peened spots that are on opposite sides of the article, simultaneously laser shock peened, and transversely offset from each other. Each of the low energy first and second laser beams having a level of energy of between 1-10 joules.

Abstract: A method to laser shock peen articles such as a gas turbine engine rotor blade with first and second oblique laser beams to form pairs of longitudinally spaced apart first and second laser shock peened elliptical spots that are on opposite sides of the article or blade and transversely offset from each other. The oblique laser beams are fired at a portion of the leading or trailing edges of the blade at first and second oblique angles with respect to opposite surfaces of the edge. Another method laser shock peens the leading and trailing edges of gas turbine engine integrally bladed rotors and disks that are blocked by other rows of blades by firing the laser beams at compound angles such that the beams are aimed at the first and second oblique angles with respect to the surfaces of the edge and at a third oblique angle with respect to a rotor axis.

Abstract: A method for single sided laser shock peening an article includes laser shock peening a laser shock peening surface on a first side of the article while maintaining an opposite second surface on a back side of the article in acoustic communication with a shock attenuating material. The second surface is opposite the laser shock peening surface. The shock attenuating material is a material that does not allow tensile waves to be reflected back off the back side through the article. The shock attenuating material may be a liquid metal and the article made from a titanium alloy. One such article is a gas turbine engine airfoil of an integrally bladed disk and the surfaces may be on an edge of the airfoil. The shock attenuating material may be one that dissipates compressive waves or reflects back compressive shock waves caused by the laser shock peening.

Abstract: An intermetallic article such as a gas turbine engine component and method of manufacture thereof includes a region having compressive residual stresses imparted by laser shock peening (LSP) extending into the article from a laser shock peened surface. One embodiment includes a turbine or compressor blade with an intermetallic airfoil having a leading edge and at least one laser shock peened surface extending radially along at least a portion of the leading edge with a region having compressive residual stresses imparted by laser shock peening (LSP) extending into the intermetallic airfoil from the laser shock peened surface.

Abstract: A method for laser shock peening rotor blade leading and trailing edges of gas turbine engine integrally bladed rotors and disks that are not blocked by other rows of blades. The method includes continuously firing a stationary laser beam, which repeatable pulses between relatively constant periods, along at least a portion of leading or trailing edges of the blade, with the laser beam aimed at an oblique angle with respect to a surface of the edge such that laser pulses form overlapping elliptical shaped laser spots. In the exemplary embodiment of the invention, the elliptical shaped laser spots have an overlap of about 50% and are on the order of 11.7 mm by 4 mm in diameter. Another method is for laser shock peening rotor blade leading and trailing edges of gas turbine engine integrally bladed rotors and disks that are blocked by other rows of blades.

Abstract: A method to laser shock peen articles such as a gas turbine engine rotor blade with first and second oblique laser beams to form pairs of longitudinally spaced apart first and second laser shock peened elliptical spots that are on opposite sides of the article or blade and transversely offset from each other. The oblique laser beams are fired at a portion of the leading or trailing edges of the blade at first and second oblique angles with respect to opposite surfaces of the edge. Another method laser shock peens the leading and trailing edges of gas turbine engine integrally bladed rotors and disks that are blocked by other rows of blades by firing the laser beams at compound angles such that the beams are aimed at the first and second oblique angles with respect to the surfaces of the edge and at a third oblique angle with respect to a rotor axis.

Abstract: A method for laser shock peening an article by simultaneously firing low energy first and second laser beams to form pairs of longitudinally spaced apart first and second laser shock peened spots that are on opposite sides of the article, simultaneously laser shock peened, and transversely offset from each other. Each of the low energy first and second laser beams having a level of energy of between 1-10 joules.

Abstract: The present invention is a method for operating a gas turbine engine airfoil having leading and trailing edges subject to FOD (foreign object damage) damage. The method includes inspecting the airfoil along at least a first one of the edges having at least a first laser shock peened patch along the first one of the edges, ascertaining FOD lengths of foreign object damage (FOD) extending from the first one of the edges into the airfoil within the patch, and allowing the airfoil to remain in service without repair if the FOD lengths are up to a maximum length of about one-half of a width of the laser shock peened patch, as measured from the edge.

Abstract: A laser shock peening system includes an apparatus and method that senses a thickness of laser transparent confinement media flow, such as water. In one embodiment, the apparatus indicates a proper thickness, in another embodiment, the apparatus controls the flow rate of the confinement media using signals from probes of the apparatus. A first probe is used to sense a predetermined minimum thickness and another embodiment further includes a second probe to indicate a predetermined maximum thickness of the confinement media.

Abstract: An on the fly method of laser shock peening a gas turbine engine part by continuously moving a metallic gas turbine engine part while continuously firing a stationary laser beam, which repeatably pulses between relatively constant periods, on a portion of the part with sufficient power to vaporize material on the surface of the portion of the part with the pulses around laser beam spots formed by the laser beam on the surface and form a region having deep compressive residual stresses extending into the part from the laser shock peened surface. Flowing a curtain of water over the surface upon which the laser beam is firing while moving the part until the laser shock peened surface is completely covered by laser beam spots at least once. The surface may covered by a paint which is then the material used to produce the plasma or the surface may be unpainted and the metal of the part is used to produce the plasma.

Abstract: The present invention includes a method of repairing an annular metallic article and the repaired article itself which has an axially extending annular support and a projection generally radially extending therefrom. The projection has an associated operating radial height as measured from a radially facing annular first surface of the support and an associated shape. An upper portion of the projection is removed forming a stub extending away from the first surface and having a bonding surface at a stub end spaced apart from the first surface. A metallic material is metallurgically bonded to the bonding surface forming an annular heat affected zone in the stub bounded by the bonding surface. A first portion of the metallic material is removed to restore the projection to the operating height and shape. At least one annular outer surface of the tooth extending over at least a portion of the heat affected zone is laser shock peened, preferably after the first portion of the metallic material is removed.

Abstract: A test coupon is formed from a metallic strip having opposite first and second sides that generally define a plane of the strip and the strip includes a laser shock peened patch of the strip that has first and second laser shock peened surfaces on the first and second sides, respectively, first and second laser shocked regions having deep compressive residual stresses imparted by the laser shock peening extending into the strip from the first and second laser shock peened surfaces, respectively, and a deflection of a portion of the strip from a position of the portion before the laser shock peening. The deflection is formed by the laser shock peening such that at least a part and preferably substantially all of the deflection lies in the plane and the test coupon preferably includes an indicating means to indicate the deflection.

Abstract: A gas turbine engine airfoil assembly for damping airfoil vibrations includes a metallic airfoil having an outer surface and a chordwise extending cavity beneath the outer surface of the airfoil. A damper is trapped within the cavity and a region in the airfoil surrounding the cavity has compressive residual stresses imparted by laser shock peening. The damper is preferably a chordwise extending linear wire having a distal end tacked down within the cavity. The invention includes a method for constructing the assembly for damping airfoil vibrations.

Abstract: A method for quality assurance of a laser process and more particularly a laser shock peening process that uses a test coupon having a deflection formed by a laser firing. The test coupon is from a metallic strip having opposite first and second sides that generally define a plane of the strip and the strip includes a laser shock peened patch of the strip that has first and second laser shock peened surfaces on the first and second sides, respectively, first and second laser shocked regions having deep compressive residual stresses imparted by the laser shock peening extending into the strip from the first and second laser shock peened surfaces, respectively, and a deflection of a portion of the strip from a position of the portion before the laser shock peening. The deflection is formed by the laser shock peening such that at least a part and preferably substantially all of the deflection lies in the plane of the strip and the test coupon preferably includes an indicating means to indicate the deflection.

Abstract: A method of laser shock peening a gas turbine engine object continuously firing a stationary laser beam, which repeatably pulses between relatively constant periods, on a portion of the object with a low power laser beam, on the order of 3-10 joules, to vaporize material on the surface of a portion of a part made of a strong hard metal, such as a titanium alloy. Laser pulses around small laser beam spots, on the order of 1 mm in diameter, are used to vaporize material on the surface of the portion of the object with the pulses around laser beam spots formed by the laser beam on the surface and form a region having deep compressive residual stresses extending into the object from the laser shock peened surface. Flowing a curtain of water over the surface upon which the laser beam is firing while preferably moving the object until the laser shock peened surface is completely covered by laser beam spots at least once.

Abstract: A crack weld repair and method, particularly, for a gas turbine engine blade or other metallic component in the engine, providing a metallic substrate, a metallic filler bonded onto a substrate bond surface on the metallic substrate, and a region having deep compressive residual stresses imparted by laser shock peening extending into the substrate beneath the substrate bond surface. One embodiment provides a laser shock peened surface below the weld material filled void in a damaged area of the component forming a region of deep compressive residual stresses imparted by laser shock peening (LSP) extending from the laser shock peened surface into the component. Optionally, the surface over the repaired area of the weld filled void may also be laser shock peened forming a second region of deep compressive residual stresses imparted by laser shock peening (LSP) extending from the laser shock peened surface into the weld repair.

Abstract: A dovetail assembly for mounting blades with dovetail roots axially into disk dovetail slots around a disk periphery which is subject to a tensile stress field due to centrifugal and thermal growth induced forces generated by the rotor when the rotor is rotating. The dovetail assembly has stress risers each in the form of a transition fillet between a neck or an area of minimum width and a pressure face which is designed to be a contact surface between complementary blade dovetail roots and disk dovetail slots formed between adjacent disk posts. The region around the stress riser has deep compressive residual stresses imparted by laser shock peening and is radially adjacent the stress riser and extends inward from a laser shocked surface of the component along the transition fillet.

Abstract: A method of forming a thermal barrier coating on an article designed for use in a hostile thermal environment, such as turbine, combustor and augmentor components of a gas turbine engine. The method is particularly directed to increasing spallation resistance of thermal barrier coatings composed of an aluminum-containing bond coat formed on the surface of an article, and an insulating ceramic layer overlaying the bond coat. Processing steps include forming the bond coat on the surface of the article, and then treating the surface of the bond coat with laser energy so as to form a diffusion barrier layer of alumina. Thereafter, a ceramic material is deposited on the surface of the diffusion barrier layer so as to form the insulating ceramic layer. A preferred technique for the treating step is to scan the surface of the bond coat with an ultraviolet laser beam characterized by an appropriate beam geometry and fluence to yield the desired diffusion barrier layer.

Abstract: An on the fly method of laser shock peening a gas turbine engine part by continuously moving a metallic gas turbine engine part while continuously firing a stationary laser beam, which repeatably pulses between relatively constant periods, on a portion of the part with sufficient power to vaporize material on the surface of the portion of the part with the pulses around laser beam spots formed by the laser beam on the surface and form a region having deep compressive residual stresses extending into the part from the laser shock peened surface. Flowing a curtain of water over the surface upon which the laser beam is firing while moving the part until the laser shock peened surface is completely covered by laser beam spots at least once. The surface may covered by a paint which is then the material used to produce the plasma or the surface may be unpainted and the metal of the part is used to produce the plasma.

Abstract: A method of laser shock peening a gas turbine engine article by loading the article such that a portion of the article to be laser shock peened is placed in a loaded condition while the portion is laser shock peened using a laser to fire a laser beam with sufficient power to vaporize material on a laser shock peening surface of the portion of the article to form a region in the portion having deep compressive residual stresses imparted by the laser shock peening process extending into the article from the laser shock peened surface. The loaded condition may be either in compression or preferably tension.