(Project financed by the Deutsche Forschungsgemeinschaft)
Description:
The systematic investigation of the correlation of microstructure and forming behavior of ordered Iron-Aluminides is realized in a two-stage strategy. In the first step, process relevant characteristics as well as deformation behavior during hot and warm rolling, microstructure and texture of the as-cast condition as well as their development in dependence of different rolling parameters and the characteristics of the produced sheet metal of the binary Fe3Al-alloy are investigated. In the second step, the characteristics and influences of the related alloy elements are examined. The hot forming behavior is analyzed dependent upon temperature and deformation rate. Suitable rolling parameters are determined. First results show the effects of deformation on the ductility. The critical temperatures of the order transitions A2-B2 as well as B2-D03 and the temperatures of further transformation processes are determined with the help of DTA-investigations. The developed thermomechanical process is able to produce thin sheet material from the applied alloys. The texture evolution during rolling as well as in subsequent heat treatments is examined with different methods. The nucleation mechanisms of recrystallization is examined. Especially the influence of secondary phases on this nucleation behavior is observed more closely.
Publications:
[1] Konrad J, Zaefferer S, Raabe D. GeNF Experimental Report 2003;1:183.
[2] Konrad J, Zaefferer S, Schneider A, Raabe D, Frommeyer G. Intermetallics; submitted.
[3] Konrad J, Zaefferer S, Schneider A. Materials Science Forum 2004;467-470:75.
Figures:
Fig. 1: Micrographs (LOM) and pole-figures of the corresponding crystallographic texture of the as cast Fe-26at.%Al alloy. A fiber texture with the <100> fiber axis in solidification direction. This results in a <100> in ND texture for the major part of the sample. The pole-figures were measured by neutron diffraction at the FRG-1 (TEX2), GKSS, Institute of Materials Research in Geestacht, Germany.
Fig. 2: Map of the kernel average misorientation (each point orientation compared to the neighboring points up to the 3rd nearest neighbors) calculated from EBSD data. Blue areas represent a low local misorientation characteristic for growing recrystallized grains. Preferred nucleation at second-phase particles (PSN).
Fig. 3 : SEM picture and diffraction patterns of secondary phase particles. Two different Laves-Phases were identified applying a combination of EBSD and EDX
