1.5.1 Light microscope images
Images of etched specimen at 100, 200, 500 and 1000 times magnification. The duplex brass microstructure can be seen with distinct difference in etch response between the two phases. Alpha phase appears bright and beta phase darker. Lead particles are etched dark. Grain boundaries in the beta phase are visible to some extent, and also a difference between grains which was not seen in the former material with smaller diameter). From EBSD we learn that the beta phase has a less strong texture in ED in this material.
Etching: 5g ferric chloride + 10ml conc. hydrochloric acid + 100 ml de-ionised water.
Specimen surface was parallel with extrusion direction (X=ED). Position ¼ depth.
Composition of CW617N
1.5.2 EBSD/EDS analysis in the SEM
EBSD analysis with 1 µm step size
The material show a fine grained duplex microstructure consisting of alpha-beta phase, and lead particles. In this limited area it is difficult to make assumptions about texture.
Specimen surface was parallel with extrusion direction (X=ED). Position ¼ depth.
Surface was OP-S-polished.
Grain- and phase boundaries
In this material there is a tendency to have low angle boundaries, mostly in the beta phase. In the previous IPF maps there are shifts of colour within grains. The assumption would be that some plastic deformation occurred after recrystallisation during extrusion.
Phase boundaries are light blue (aqua).
Grain boundaries (>15°) are black.
Low angle boundaries (2-15°) are thin black.
Twin boundaries (60<111>) are red.
EDS mapping in parallel to EBSD analysis
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Large area mapping – Many (>40) analyses stitched together
The large area make statistics for grain size, phase fractions, texture, etc. better and now it is obvious that there ARE preferred orientations in X (ED). Pole figures for both phases show textures for the alpha phase <100>&<111>//ED, and for the beta phase <110> // ED.
Phases
Alpha: 63%
Beta: 37%
Grain size, area weighted distribution
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