Measurements on cracktips in stainless steel AISI 321 by using a new positron microprobe

High resolution positron microscopy provides a new method for non-destructive investigations of plastic deformation with spatial resolution in the micron range. As positron annihilation is highly sensitive to lattice defects, low concentrations of dislocations are detectable, so that the plastic zone in front of a cracktip appears larger than in comparable metallographic methods. To demonstrate this, a plastic zone in the common stainless steel AISI 321 is imaged with the Bonn Positron Microprobe BPM.with a spatial resolution of 20 mm. q1999 Published by Elsevier Science B.V. All rights reserved.