CW510L | CuZn42 quantitative phase analysis

In a standard alpha-beta brass alloy, the beta phase content was to be determined using image analysis (Imagic).

Whilst brass etching agents cause the beta phase to be etched to a degree that is partly lighter and partly darker than the alpha phase (Figure 1), clamp etching (Figure 2) allows the lighter alpha phase and the consistently darker beta phase to be distinguished more clearly by image analysis.

First, a white balance was performed on the alpha phase, Figure 3. Direct evaluation of the alpha phase yields a content of 40 vol-%, Figure 4. If the beta phase is evaluated instead, scratches are also detected, which slightly distorts the result, Figure 5. The image processing step ‘Median Circle Option’ in Imagic introduces a certain amount of blurring into the image, causing the scratches to ‘blur’, Figure 6.
The beta content is approximately 60 vol-%.