Nondestructive characterization of material states and evaluation of material properties: Kap.3

The process approaches and measurement techniques developed by the IZFP are presented. The caracterization of the initial state of component with respect to its homogeneity and isotropy of its properties is possible by way of ultrasonic and magnetic techniques. Detecting areas of plastic deformation is possible via ultrasonic and magnetic techniques. Positron annihiliation offers the advantage of bing independent of residual stress for the most part. The detection and characterization of creep damage has not been possible to date with the required degree of detection sensitivity. The potential offered by ultrasonic and magnetic techniques for the early detection of damange, i.e. for reliably detecting advanced prosity, is limited. It seems necessary to utilize ohter creep-induced structural changes via instrumentation and monitoring technology. Experimental studies for detecting hydrogen-induced embrittelment and stress-sorrosion cracking demonstrate the possibilities offered by elect ric and magnetic techniques