If a grid is too dense, multiple points will land on a single small particle. This violates the rule of independent observations and skews the statistical standard deviation. Ensure point spacing exceeds the average feature diameter.
ASTM E562-19 outlines a systematic manual point-count procedure to determine the volume fraction of microstructural constituents in materials, utilizing a grid-based overlay for statistical estimation. This standard, which supports accurate phase identification, provides a 95% confidence interval for measuring constituent ratios in metals, ceramics, and composites. Purchase the official ASTM E562-19 PDF from ASTM International ASTM International astm e56219 pdf
Volume Fraction (VV)≈Area Fraction (AA)≈Point Fraction (PP)Volume Fraction open paren cap V sub cap V close paren is approximately equal to Area Fraction open paren cap A sub cap A close paren is approximately equal to Point Fraction open paren cap P sub cap P close paren If a grid is too dense, multiple points
It can be used for any number of distinct phases. which supports accurate phase identification