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M: Metallphysik

M 16: Phasenumwandlung I

M 16.1: Vortrag

Samstag, 5. März 2005, 09:15–09:30, TU H1058

In-situ observation of Short Range Order and Precipitation Processes in Ti-V by High Energy X-Ray Diffraction — •Ingo Ramsteiner, Andreas Schöps, Harald Reichert, and Helmut Dosch — Max-Planck-Institut für Metallforschung, Stuttgart

Phase transformations, especially precipitation processes, are a key factor in alloy design. Therefore, they are of major interest in materials science. Understanding these processes in the framework of statistical thermodynamics requires knowledge about the atomic interaction potentials between the alloy constituents. Experimentally, these parameters can be accessed via the diffuse scattering caused by the configurational short range order (SRO) and lattice distortions. With the high energy monochromatic Laue technique we present a tool to study both phenomena simultaneously in situ in the bulk of a macroscopic single crystal. Recording the scattered intensity with a 2D detector reveals distinct precipitate Bragg peaks embedded into the diffuse scattering of the matrix.

We present an in situ case study of bcc Ti-V. Apart from the SRO, growth and dissolution of two different types of precipitates are observed, depending on the anneal temperature. HRTEM experiments have been conducted to complement and verify our results.