ECOBRASS CW724R, round bar, d=19 mm

1.9.1 Light microscope images

Images of etched specimen at 100, 200, 500 and 1000 times magnification. Duplex phase brass microstructure, alpha and Kappa phase, with grains aligned in the ED. The etch effect of crystallographic orientations makes grains easy to distinguish, but the phases are not very easy to separate from these images. Small particles can be seen, they are etched dark, they appear to be round and homogeneously distributed. EDS results propose that they are mainly lead particles.

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.

ECOBRASS CW724R, 100x Magnification

ECOBRASS CW724R, 200x Magnification

ECOBRASS CW724R, 500x Magnification

ECOBRASS CW724R, 1000x Magnification

Composition of ECOBRASS CW724R

1.9.2 EBSD/EDS analysis in the SEM

EBSD analysis with 1 µm step size

The material show a duplex, banded micro-structure consisting of alpha and kappa phase. In this limited area it is difficult to make assumptions about texture. In literature it is reported that CW724R also could contain Gamma phase but in this analysis Gamma phase description was not included during analysis.

Specimen surface was parallel with extrusion direction (X=ED). Position ¼ depth.

Surface was OP-S-polished.

FSD image of the area for EBSD analysis.

IPF-Z EBSD map with colours according to crystal orientations in Z direction (transverse dir.).

EBSD phase map, alpha phase is red and kappa phase yellow. Grain boundaries (>15°) are included.

EBSD map showing IPF in X direction (extrusion dir.).

Alpha phase crystal orientations (ED)

Kappa phase crystal orientations (ED)

Grain- and phase boundaries

In this material there is a tendency to have low angle boundaries. 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 kappa phase <1010> // ED.