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MM: Fachverband Metall- und Materialphysik

MM 16: Phase transitions II

MM 16.2: Vortrag

Dienstag, 27. März 2007, 12:00–12:15, H4

The contribution of elastic strain onto the early stage of decomposition in a Cu1,7at%Fe alloy — •Thomas Rademacher, Talaat Al-Kassab, and Reiner Kirchheim — Institut für Materialphysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany

The early stage of decomposition of supersaturated Cu Fe alloys has been previously intensely studied in the course of classical homogeneous phase separation. Up to now contributions of the strain energy to the decomposition process and its influence on the early stage has been neglected in this system.

In a former study Heinrich et al. (Mat. Sci. Eng. A353 (2003) 92-98) showed that decomposition at low temperatures of supersaturated Cu Co alloys is mainly controlled by strain energy. Hence, cluster’s size and morphology are biased and the formation of chains of precipitates in the elastic soft <100> directions of the Cu-matrix is promoted.

In the current study, these phenomena will be investigated for Cu1,7at%Fe after a heat treatment at 722 K for times ranging from 1 to 48 hours. Analyses are performed by utilizing the Tomographic Atom Probe (TAP) and the newly developed computer assisted Field Ion Image Tomography (CFIIT). Amongst others, a chain like formation of precipitates can be observed in our results as well. By means of computer based methodical analyses the directions and distances of alignments of precipitates can be ascertained. The consistency of the results with calculations established by Miyasaki and Yamauchi/ De Fontaine in terms of linear anisotropic elasticity theory will be presented and discussed.