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    1.2.1 Light microscope images

    Images of etched specimen at 100, 200 and 500 times magnification. Single phase brass microstructure with grains aligned in the ED. Etch effect homogeneous in the alpha phase, not very sensitive to crystallographic orientations in this case. Lead particles in streaks along the ED.

    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.

    CW602N, 100x Magnification CW602N, 100x Magnification
    CW602N, 200x Magnification CW602N, 200x Magnification
    CW602N, 500x Magnification CW602N, 500x Magnification
    Composition of CW602N Composition of CW602N

    1.2.2 EBSD/EDS analysis in the SEM

     

     

     

    EBSD analysis with 1 µm step size

    The material show a microstructure consisting of alpha phase with some beta phase. 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.

    SED image of the area for EBSD analysis. Streaks of Pb particles along ED is seen.
    IPF-Z EBSD map with colours according to crystal orientations in Z direction (transverse dir.).
    EBSD phase map, alpha phase is red and in beta phase is blue. Grain boundaries (>15deg) and low angle boundaries (2-15deg) are included.
    EBSD map showing IPF in X direction (extrusion dir.).
    Alpha phase crystal orientations (ED)
    Beta phase crystal orientations (ED)

    Grain- and phase boundaries

    In this material there are not a lot of low angle boundaries. The assumption would be that recrystallisation occurred after 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. 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

    Some segregation of Cu/Zn is seen and small amounts of beta phase was found in the microstructure. Pb particles in streaks. Small Fe, P, and Bi particles could be detected as well, but As and other elements etc. were not detected which indicates low levels and very small particles if present.

    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 alpha texture with strong <100>//ED (48 times random) and weaker <111>//ED.

    Beta texture is a strong <110>//ED, 27 times random.

    Alpha: 99.7% Beta: 0.3%
    Alpha texture: <100>//ED 48 times random. Weaker texture component <111>//ED
    Beta texture: <110>//ED 28 times random

    Grain size, area weighted distribution

     

     

    There is a very small fraction of beta phase. Fine grain size!