Dresden 2003 – scientific programme
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M: Metallphysik
M 21: Mechanische Eigenschaften II
M 21.4: Talk
Tuesday, March 25, 2003, 12:30–12:45, IFW B
High Cycle Fatigue in metals: A pop-out mechanism in thin Al films — •Christoph Eberl1, Ralph Spolenak2, Oliver Kraft3, Franz Kubat4, Anton Leidl4, and Eduard Arzt1,2 — 1Institut f/"ur Metallkunde der Universit/"at Stuttgart — 2Max-Planck Institut f/"ur Metallforschung Stuttgart — 3Forschungszentrum Karlsruhe — 4EPCOS AG
We present a novel pop-out mechanism of high cycle damage formation in thin metal films. Quantitative post test analysis as a function of testing time, power density and temperature revealed a direct correlation between extrusion density and film performance. The effect of alloying, though in general beneficial, will be critically assessed. The kind of damage observed will be examined in the light of the local mechanical stress state. A combination of measurement for thermal stresses (substrate curvature, X-ray diffraction) and finite element as well as P-Matrix based modelling allowed the complete stress tensor to be determined. The mechanistic insight obtained in this way will be a key element in life-time prediction of devices undergoing a large number of loading cycles.