Non-destructive positron-lifetime measurements during fatigue of stainless steel AISI 316L using a mobile positron beam
Fatigue in metals and other materials poses a great threat in industry while it cannot be detected. A technique to identify the early stages of fatigue is being developed to help industrial workers replace equipment parts before they become dangerous. Positron lifetime measurements are an ideal way to non-destructively test materials put under stress and fatigue. A stream of positrons from a Selenium/Arsenic generator is bombarded against a sample of stainless steel kept under stress to induce fatigue. Positron decay is measured using spectroscopy. Positrons will decay rapidly when in contact with electrons which in a fully sound material results in rapid disintegration of the positron stream. A material with a defect or hole will have a gap in the electron structure allowing positrons to congregate. These defects are seen on the spectrometer as longer living positrons that are protected from electron activity. This technique will replace earlier defect detection methods that only operated on a microscopic scale and were often material dependent. The positron lifetime measurements will be adaptable to all materials and will detect a defect as soon as it starts to occur.
Bibliographic Reference: Article: Applied Physics Letters (2000), further details unknown
Availability: Applied Physics Letters (Journal)
Record Number: 200012132 / Last updated on: 2000-07-21
Original language: en
Available languages: en