Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7973507 | Materials Science and Engineering: A | 2018 | 19 Pages |
Abstract
The high temperature creep properties of next generation cast and wrought AD730 superalloy have been investigated taking into consideration three microstructural parameters: the grain size, the presence of grain boundaries and the γⲠprecipitates size and distribution. Definitive analysis of the influence of the grain boundaries and γⲠprecipitates size distribution has been enabled by the study of single crystalline versions of the polycrystalline alloys studied. At high temperature (equal to or in excess of 850 °C), the grain size controls creep properties. Comparisons between polycrystalline and single crystalline specimens indicate that the grain boundaries provide a strengthening effect, especially in the small strain regime. At intermediate temperature (700 °C), the γⲠprecipitates size is the main creep-rate controlling parameter. In this temperature domain, creep strength seems to be mainly controlled by dislocation motion. A very striking grain boundary strengthening mechanism is observed at small creep strain and intermediate temperature.
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Authors
Louis Thébaud, Patrick Villechaise, Coraline Crozet, Alexandre Devaux, Denis Béchet, Jean-Michel Franchet, Anne-Laure Rouffié, Michael Mills, Jonathan Cormier,