Reply to “comments on ‘grain size measurements using the point-sampled intercept technique’” by G. F. Vander Voort and A. M. Gokhale

Abstract

Here, the authors respond to the technical points which were raised by G.F. Vander Voort and A.M. Gokhale. First, the basic point of the original paper is to distinguish between the conventional'' method of measuring a microstructural property which is usually called Grain Size,'' and the Gundersen method, or volume-weighted mean volume. It is true that the latter method has heretofore been primarily applied in the biological and medical field, and that it is a relatively new method. It was the point of the note that it has the potential for considerable applicability to materials specimens, particularly to sintered ceramics in which the traditional method of measuring particle size has been by sieving methods. Vander Voort and Gokhale (V-G) correctly point out that the conventional method has been sanctioned as an ASTM'' method, currently ASTM E112, for more than 75 years, and that it does not measure the actual size distribution of the grains but instead measures the amount of grain boundary surface area per unit volume (stereological notation S[sub V]). V-G also mentions the other ASTM method, which counts the grains per unit area on a section plane and actually measures the length of triple lines between grains inmore » the microstructure. This is yet a different parameter (stereological notation L[sub V]) which also has little to do with the actual size of grains. The authors had not raised this point because of its additional prospect for introducing confusion, but it should be noted that the two methods are only able to agree on a numeric index of grain size'' due to the introduction of artificial constants and an underlying set of assumptions about grain size and shape.« less