Quantitative estimation of particles with large size variation
Abstract
Quantitative evaluation of particles of the size more than 1 µm, inhomogeneously distributed in matrix, is successfully carried on by automatic analysis of images obtained with light microscope (LM - QM). Stereological assessment of smaller particles requires applying of equipment with higher resolution, mainly scanning electron microscope (SEM - QM), which enables more accurate measurements of area fraction AA.
After common LM - QM assessment, the authors have suggested the SEM - QM measurement, but only in the areas among large, already measured particles. Such LM + SEM - QM method seems to join advantages of both microscopy techniques as well as to avoid their drawbacks. It is of importance that area fractions obtained this way are not additive and following formula should be employed:
AA=(AA)LM +(AA)SEM-(AA)LM.(AA)SEM ≤1
This scheme has been used to assess carbide phase of new nonledeburitic high-speed steel and to correlate carbide size, shape and arrangement with tool wear resistance. The obtained findings are indicative of significant differences between carbides of new tool alloys and conventional grades of high-speed steels (HSS).