TITANIUM PRIOR-BETA GRAIN VOLUME DISTRIBUTION BY QUANTITATIVE SERIAL SECTIONING TECHNIQUES

A prior-beta grain (PBG) volume distribution was determined for a titanium IMI 829 disk forging. Individual PBGs were identified and tracked by serial sectioning at sample areas adjacent to the disk bore and rim. Each grain's volume and surface area were calculated from a set of paired contours and elevations. Fisher and Student's t tests showed that grains taken from the two sample areas were drawn from the same distributio at a 95% confidence level. A three-parameter Weibull distribution function was used to fit the grain volume data. PBG surface area versus volume was compared to a sphere's surface area versus volume curve. A computer-aided design and manufacturing system, CATIA, was used to reconstruct several grains' three-dimensional shape.