Articles



Publication single view

Article

Title: Material Science with Positrons: From Doppler Spectroscopy to Failure Prediction
Author(s): M. Haaks Person, P. Eich Person, J. Fingerhuth Person and I. Müller Person
Journal: Advances in Solid State Physics
Editor: Rolf Haug
Year: 2008
Volume: 47
Series: Advances in Solid State Physics
Pages: 289-300
Publisher: Springer Berlin / Heidelberg
Affiliation: 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
File URL: http://www.springerlink.com/content/k4lx118586wl3227/
Abstract: 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.

Back to the list view