Characteristic grain size: Part I description and definition

Characteristic grain size, G _c, is defined in the present paper. It indicates an intrinsic size of grain for a given system, and has the following advantages over the average grain size which is based on a statistical mean value of the linear intercept length of grains: (1) The characteristic grain size G _c has clear and determined geometric meaning, i. e. G _c refers to two times of the area-weighted average height of the surface elements to the centroid of grain or the average length of the chord through the centroid of grain; (2) The value of G _c can be directly obtained without introducing any correcting factors such as grain shape or grain size distribution factors. Generally, G _c is larger than the average grain size G when the Heyn intercept method is adopted for the grain size measurement. Project supported by the British Council Academic Link Scheme Synopsis of the first author Cao Shunhua, lecturer, born in Jan. 1965, strong interest in the following research areas: ceramic composites, FGMs, prototype design of WC-Co alloys, and preparation of β-SiC and sialon powders.