Novel lamellar in situ composite materials in the Al-rich part of Fe-Al
Xiaolin Li, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, GermanyFabian Bottler, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, GermanyRobert Spatschek, IEK-2, Research Center Julich, Jülich, GermanyAnke Scherf, Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology (KIT), Karlsruhe, GermanyMartin Heilmaier, Institute for Applied Materials (IAM-WK), Karlsruhe Institute of Technology (KIT), Karlsruhe, GermanyFrank Stein, Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
Phase equilibria and microstructures in the Al-rich part of the Fe-AI system (50-80 at.%) were investigated by studying heat-treated alloys of fixed compositions as well as a series of diffusion couples resulting in a detailed, revised phase diagram.
As a consequence of a very rapid eutectoid decomposition reaction at 1095 °C, alloys with about 61 at.% AI form a fine-scaled, fully lamellar microstructure consisting of the phases FeAI and FeAI2. A series of heat treatments for up to 7000 h was conducted at different temperatures between 600 and 1000 °C to investigate the coarsening kinetics of the lamellar microstructure. Simulations based on the phase field method were also applied.
In order to understand the effect of ternary elements on the morphology and properties of the lamellar material, microstructure, transition temperatures and mechanical behaviour of lamellar Fe-61AI based alloys with additions of Ti, Cr, Cu, Mo (always 2 at.%), or B (0.05-0.1 at.%} were also studied. Compressions test, microhardness measurement and four-point bending tests were conducted. In addition, the influence of ternary elements B and Cu on the coarsening kinetics of the lamellar microstructure are under investigation.