Regensburg 2004 – scientific programme

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M: Metallphysik

M 22: Intermetallische Phasen

M 22.6: Talk

Wednesday, March 10, 2004, 17:45–18:00, H6

Three-dimensional finite element analysis of mismatch-induced stresses and elastic strain energy distribution around precipitates in INCONEL 706 alloy — •Vitaliy Kindrachuk, Nelia Wanderka, Weiye Chen, and John Banhart — Hahn-Meitner-Institut Berlin, Glienicker Str. 100, 14109 Berlin, Germany

The good mechanical properties of Inconel 706 up to 600^∘C are due to strengthening by γ′, γ″ and γ′-γ″ precipitates. To better understand the microstructure behaviour (the morphological and phase changes) during the heat treatment is the stressed state on the interfaces of great interest. The three-dimensional finite element (FE) analysis was used to investigate the stress and strain energy features arising from a mismatch of crystal lattices of coexisting phases.

The FE model was built based on characterization of the precipitates and matrix by three-dimensional atom probe, high resolution transmission electron microscopy, X-ray and synchrotron measurements. The precipitates were modelled to have an oval morphology, negative misfit and oriented parallel to the <001> lattice direction of the γ matrix. The individual precipitate variants of γ′,γ″ and γ′-γ″ co-precipitates were analysed under stress-free conditions. To obtain the long-range stress field we have simulated the combination of precipitates taking into account their mutual spatial arrangement. Prediction of the selective variant growth was realized by addition the coupling between the applied stress and the strain caused by the precipitates.