International audienceA microgrid technique has been developed for the analysis of the high-temperature micro-scale strain distribution between ferrite and austenite into duplex stainless steels. The local strain is measured by micro-extensometry using square microgrids engraved on flat specimens by electro-lithography. The sample with microgrids on the surface and preliminary imaged with high definition scanning electron microscope (SEM), is inserted in a plane strain compression specimen to be deformed under conditions representative of hot rolling. After deformation, the sample is extracted from the compressed block and the surface is again analyzed by SEM and image processing to determine the strain field. The strain is heterogeneously distributed with a strong localization of the deformation, in the form of shear bands located within the ferrite and at the vicinity of the austenite/ferrite interphase boundaries. These strain maps provide useful informations about the rheology of the phases as well as about the local conditions at the origin of the damage proces

tron diffraction pattern stems from a significantly smaller volume than in the SEM. Additionally, dislocations are visible with the TEM and so localization of subgrains or cell structures is much easier.A TEM image of c-fibre orientations is shown in Figure 7. Subgrain structures are visible here too. However, in this case, the subgrains have a longitudinal shape and are separated by much sharper boundaries. The misorientations between neighboring subgrains are significantly higher as compared to the a-fibre structures. Values of about 1.5±6 were found. Obviously these structures can be resolved by the EBSD system because they show sharper boundaries and higher misorientations than a-fibre subgrains.This comparison of EBSD results with TEM observations shows that not all subgrain structures are clearly resolved by the EBSD system. In this context, it is very useful to take additional information into account. For example, images provided by a backscatter detector often show cell structures at places where an orientation map only shows continuous orientation gradients. This indicates that using both methods (EBSD + SEM with strong orientation contrast) in combination can prevent misinterpretation of EBSD data.The recrystallization behavior of laboratory-processed AISI409 ferritic stainless steel sheet has been studied with a focus on texture inhomogeneity and ªsluggishº recrystallization kinetics. This communication focuses primarily on observations made by electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM). Pronounced texture gradients were observed in some grain orientations and correlated with the deformation-induced substructure. The strong pinning of some boundaries has been linked, not only to textural effects, but also to the precipitation of fine titanium carbonitrides.Tailoring the physical and mechanical properties of steels through careful engineering of microstructure and texture has been responsible for many of the recent developments in light-weight, high-strength, and highly formable alloys. Demands for further improvements in material properties require ever more sophisticated descriptions of microstructure evolution under complex processing paths. Widespread availability of new techniques, such as EBSD, are now being used to provide a fully quantitative link between microstructure, texture, and mechanical properties. Of the many properties that must be controlled via processing, optimization of formability continues to be a priority for ferritic steel producers. Control of plastic anisotropy via the bulk texture of the final product is crucial in this regard and consequently has been heavily studied, particularly for carbon steels. [1] While COMMUNICATIONS 570

An experimental study of the microstructural evolution attending recrystallization of cold-rolled Ti-stabilized ferritic stainless steel is presented. Particular attention is paid to the slow approach to full recrystallization. It is shown that this "sluggish" recrystallization can be attributed to the heterogeneity of microstructure and texture resulting from the processing of the material. In particular, it is shown that the presence of fine Ti(C,N) precipitates acts to significantly hinder the final approach to full recrystallization.

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