Positron Systems Works with Lockheed Martin Aeronautics to Identify Beneficial Cold Expansion Effects in Metal Alloys.Business Editors BOISE, Idaho--(BUSINESS WIRE)--Feb. 24, 2004 Positron positron: see antiparticle. positron Subatomic particle having the same mass as an electron but with an electric charge of +1 (an electron has a charge of −1). It constitutes the antiparticle (see antimatter) of an electron. Systems, an innovator in the field of nondestructive non·de·struc·tive adj. Of, relating to, or being a process that does not result in damage to the material under investigation or testing. non and material characterization testing, has demonstrated in a project commissioned by Lockheed Martin Aeronautics that its Photon Induced Positron Annihilation (PIPA) and related technologies can reliably and accurately measure the effectiveness of cold expansion techniques in metal alloys. This capability will lead to improved inspection intervals and lower maintenance costs in the aerospace sector. Further, with PIPA's multi-layer damage assessment capability, early damage in subsurface layers can be detected, thereby providing a method for quantifying damage without component disassembly dis·as·sem·ble v. dis·as·sem·bled, dis·as·sem·bling, dis·as·sem·bles v.tr. To take apart: disassemble a toaster. v.intr. 1. . Many fastener holes in aerospace components are "cold worked" to produce a compressive com·pres·sive adj. Serving to or able to compress. com·pres  sive·ly adv. residual stress field around the hole to improve resistance to fatigue cracking. Other nondestructive testing methods cannot accurately assess the effectiveness of cold working on fastener holes in aluminum alloys due to their material characteristics. Further, current techniques are not easily deployed in the field to inspect in-use components. In the project commissioned by Lockheed Martin Aeronautics, Positron Systems utilized its PIPA and Distributed Source Positron Annihilation (DSPA DSPA Desmodus Rotundus Salivary Plasminogen Activator (vampire bat saliva-derived anticlotting agent) DSPA digital subtraction pulmonary angiography ) technologies to demonstrate that it can detect and differentiate beneficial residual stress in cold-worked fastener holes due to applied expansion levels ranging incrementally from 0% to 5.2% in 2000 series aluminum alloy. These technologies have also been shown to be effective in quantifying the effects of surface treatments such as shot peening. This capability was proven in projects completed for the National Science Foundation and other groups. These demonstrated capabilities are a significant first step towards the eventual goal of deploying a unit to inspect fastener holes and other surface treatments in the field, thereby filling a significant industry need. Results of the Lockheed Martin cold expansion study were presented in a paper during the 2003 United States Air Force United States Air Force (USAF) Major component of the U.S. military organization, with primary responsibility for air warfare, air defense, and military space research. It also provides air services in coordination with the other military branches. U.S. (USAF) Aircraft Structural Integrity Program (ASIP ASIP American Society for Investigative Pathology ASIP Application Specific Instruction Set Processor ASIP Aircraft Structural Integrity Program ASIP Arrow System Improvement Program (US DoD) ASIP Airborne Signals Intelligence Payload ) Conference in Savannah, Georgia. The study was presented by representatives of Lockheed Martin Aeronautics Company. The paper is available for download at www.positronsystems.com. About Photon Induced Positron Annihilation (PIPA) The PIPA process involves penetrating materials with a photon beam generated by a small linear accelerator linear accelerator: see particle accelerator. linear accelerator or linac Type of particle accelerator that imparts a series of relatively small increases in energy to subatomic particles as they pass through a sequence of or other techniques. This process creates positrons, which are attracted to nano-sized defects in the material. Eventually, the positrons collide with electrons in the material and are annihilated, releasing energy in the form of gamma rays Gamma rays Electromagnetic radiation emitted from excited atomic nuclei as an integral part of the process whereby the nucleus rearranges itself into a state of lower excitation (that is, energy content). . The gamma ray gamma ray Penetrating very short-wavelength electromagnetic radiation, similar to an X-ray but of higher energy, that is emitted spontaneously by some radioactive substances (see gamma decay; radioactivity). energy spectrum creates a distinct and readable signature of the size, quantity and type of defects present in the material. PIPA can detect a wide variety of damage types in a wide variety of materials. Because PIPA examines materials at the atomic level, it can detect damage at its earliest stage, before cracks appear. The technology can also determine the remaining useful life of a component and detect damage in 2nd layer materials. Pricing and Availability Positron Systems currently provides induced positron annihilation testing at the company's Test and Analysis Center. A mobile field unit is currently in development. Service price varies according to testing time, material of interest, and other customer specific criteria. About Positron Systems Founded in 2001, Positron Systems' headquarters is located in Boise, Idaho. For more information, visit the company Web site at www.positronsystems.com or call 208-672-1923, ext. 204. |
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