| Titel: |
Material Science with Positrons: From Doppler Spectroscopy to Failure Prediction |
| Autor(en): |
M. Haaks  , P. Eich , J. Fingerhuth und I. Müller |
| Journal: |
Advances in Solid State Physics |
| Editor: |
Rolf Haug |
| Jahr: |
2008 |
| Band: |
47 |
| Reihe: |
Advances in Solid State Physics |
| Seite(n): |
289-300 |
| Verlag: |
Springer Berlin / Heidelberg |
| Zugehörigkeit: |
Helmholtz Institut für Strahlen- und Kernphysik, Universität Bonn, Nußallee 14-16, 53115 Bonn, Germany |
| DOI: |
10.1007/978-3-540-74325-5_23 |
| ISBN: |
978-3-540-74324-8 |
| Datei / URL: |
http://www.springerlink.com/content/k4lx118586wl3227/ |
| Zusammenfassung: |
We describe an alternative approach for a reliable lifetime prediction employing the local concentration of lattice defects as a precursor for fatigue failure. We present positron annihilation spectroscopy (PAS) as a non-destructive technique sensitive for defect concentrations in the range relevant to plasticity in metals. The Bonn Positron Microprobe (BPM), a currently unique device, provides a fine focused positron beam with a selectable beam diameter from 5 to 200 µm assisted by an inbuilt fully functional scanning electron microscope (SEM). Using the BPM, plasticity and fatigue can be measured with a lateral resolution from some microns up to the range of millimeters. Employing laterally resolved PAS and the empirical supposition of a linear relation between the defect concentration and the logarithm of the number of fatigue cycles, the point of failure was successfully predicted on the common carbon steel AISI 1045. For a generalization of the precursor method, a minimal model of fatigue based on a cellular automaton was developed. First results from a one-dimensional implementation are presented. |
