Grain Size Measurement
Types of Grain Sizes
- Non-twinned(ferrite, BCC metals, Al)
- Twinned FCC Metals (austenite)
- Prior-Austenite (Parent Phase in Q&T Steels)
Intercept Grain Size Example: Single Phase Twinned Grain Structure
The 100X micrograph is that of a twinned FCC Ni-base superalloy, X-750, in the solution annealed and aged condition after etching with Beraha’s reagent which colored the grains. This is a much more difficult microstructure for intercept counting. The three circles measure 500 mm and P is 63 (intersections with twin boundaries are ignored).