BOISE, Idaho, January 13, 2004. Positron Systems has been awarded a Small Business Innovative Research (SBIR) contract by the National Science Foundation. Under the contract, the company will demonstrate that its Photon Induced Positron Annihilation (PIPA) technology can nondestructively detect hard alpha inclusion defects in titanium components. This research will verify that PIPA can detect this type of defect and quantify the damage.
No existing nondestructive testing method has the capability to detect this type of defect, except at or near the surface of a component. The capability to detect this type of defect will lead to superior product designs, improved maintenance procedures, and increased safety.
Commercial and military aircraft use titanium in critical structural components and especially in some rotating components used in jet engines. Hard alpha inclusions can form crack initiation sites in these components that can significantly affect their remaining useful life or lead to catastrophic failure. Current nondestructive inspection techniques available to detect these types of defects can only identify relatively large inclusions that are on or near the component surface, resulting in a high potential for missed defects.
Positron Systems will demonstrate that PIPA can detect smaller (previously undetectable) buried inclusions, earlier in the manufacturing process of the component. Positron Systems will also evaluate the technology for use in the field to assess damage buildup in installed titanium components at any point in their life cycle.
"This research award allows us to demonstrate the unique atomic level detection capabilities of Photon Induced Positron Annihilation," said Steve Bolen, president and CEO of Positron Systems. "The technology has the potential to significantly advance how the aerospace industry nondestructively detects hard alpha inclusion defects and how they assess damage build up in critical titanium components. The industry will benefit in lower inspection and inventory costs with the development of this advanced inspection capability."
PIPA will also provide an improved understanding of the impact of hard alpha inclusions and how operational conditions change the microstructural state of titanium materials. This will benefit materials research in the areas of fatigue fundamentals, crack propagation models, life assessment, and basic failure mechanisms.
The PIPA process involves penetrating materials with a photon beam generated by a linear accelerator or other techniques. This process creates positrons, which are attracted to nano-sized defects or changes in the lattice structure of the material. Eventually, the positrons collide with electrons in the material and are annihilated, releasing energy in the form of gamma rays. The gamma ray 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 including metals, polymers, ceramics, and composites. Because PIPA examines materials at the atomic level, it can detect damage at its earliest stage, from initial manufacture through failure. The technology can also determine the remaining useful life of a component and detect damage in 2nd layer materials.
Positron Systems currently provides induced positron annihilation testing at the company's Test and Analysis Center. Service price varies according to testing time, material of interest, and other customer specific criteria. Mobile systems are available on a made-to-order basis.
For more information, visit www.positronsystems.com .
Military & Aerospace Electronics