Abstract: A system and method for monitoring a laser shock peening process includes a sensor connected to a controller. The controller includes an input and a processor. The input is connected to the sensor to receive a signal indicative of a laser shock event at a workpiece. The processor is connected to the input and is configured to determine a time-of-flight of residual energy associated with the laser shock event from the workpiece to the sensor and determine peen quality from the time-of-flight of the residual energy.

Abstract: The invention provides a method for sealing arc tubes while preventing cracking of the tube. The method comprises sealing a pair of electrodes on the arc tube in a furnace. A heat shield structure is used to reduce the thermal gradient generated by the sealing process. The heat shield comprises alternating layers of thermally conducting materials and thermally non-conducting materials.

Abstract: The invention provides a method for sealing arc tubes while preventing cracking of the tube. The method comprises sealing a pair of electrodes on the arc tube in a furnace. A heat shield structure is used to reduce the thermal gradient generated by the sealing process. The heat shield comprises alternating layers of thermally conducting materials and thermally non-conducting materials.

Abstract: An ablative tape is applied onto a substrate surface. The ablative tape comprises an ablative medium comprising a polymer and dispersed metallic component. The tape is then irradiated to ablate the ablative medium. An article comprises a substrate and the ablative tape applied to the substrate.

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: A polycrystalline article is converted to a single crystal in a solid-state process. Heat is applied at a first end of the article to effect a predetermined spatial temperature profile thereat having a maximum temperature approaching a melting temperature thereof. The temperature profile is maintained to initiate conversion at the first end. The heat is moved along the article toward an opposite second end to correspondingly propagate the conversion along the article.

Abstract: A method of controlling the size of a laser beam comprises the steps of generating the laser beam with a laser, focusing the laser beam, directing the laser beam to a target, directing a portion of the laser beam to an optical detector which generates a signal representative of a fluence distribution of the laser beam, and adjusting a focal point of the laser beam based on the measured fluence distribution to control the size of the laser beam on the target.

Abstract: A laser shock peening apparatus includes a cavity dumping laser oscillator including in optical serial alignment a first mirror, a Pockels cell, a polarizer, a laser rod, and a second mirror defining a cavity having an optical length between the mirrors. The laser rod is optically pumped to generate a laser beam in the cavity, and the Pockels cell has selective wave retardation to allow the beam to oscillate between the mirrors and increase energy therein, followed in turn by dumping the beam into a laser amplifier. The laser amplifier directs the amplified pulse at a target for laser shock peening thereof. The cavity length is selected to develop a substantially square-wave laser pulse for temporally shaping the resulting pressure pulse at the target.

Abstract: A method and apparatus are provided for measuring effective focus of an electron beam directed at a target. The electron beam imparts heat flux into the target to effect a target surface temperature profile thereon. A mathematical process model is used to predict an initial iteration of the temperature profile based on operating beam parameters and based on heat transfer behavioral relationships of the target. The temperature profile is optically measured and then compared with the initial iteration to obtain a residual error therebetween. The predicted temperature profile is iterated by varying the beam focus operating parameter until the residual error is less than a predetermined value for determining the effective beam focus.

Abstract: A method is disclosed for operating an electron beam physical vapor deposition apparatus including a vacuum chamber containing an ingot disposed in a crucible, a workpiece disposed above the ingot, and an electron gun for emitting an electron beam to melt and vaporize the ingot to disperse vapors for deposition coating of the workpiece. The method includes directing a primary electron beam with a primary beam focus in a primary scanning pattern across a top surface of the ingot to melt and vaporize the ingot and develop an ingot melt pool floating atop an underlying ingot substrate. A secondary electron beam is superimposed across the ingot top surface in conjunction with the primary electron beam. The secondary electron beam has a secondary beam focus in a secondary scanning pattern to locally and transiently increase vaporization rate of the melt pool.