DEVELOPMENT OF ROCKING CURVE METHOD FOR POLYCRYSTALLINE MATERIALS. S.Ya. Betsofen, Baikov Inst. of Metallurgy, Russian Academy of Sciences, 49 Leninsky pr. Moscow 117334 Russia

The rocking curve ([[omega]]-scanning) method is successfully used for misorientation measurements of single crystals. The electron channelling patterns (ECP) method use to measure of grain orientation of polycrystalls with a variety of grain size. The time consuming procedure of this method is limited for its application for industrial scale specimens with nonuniform microstructure. In the present paper the various quantative procedures for microstructure characterization on the base [[omega]]-scanning technique are developed for polycrystals with grain size more than 20 um. The principal advantages of the method is that it allows to make the non-destructive measurement and also it gives more statistic validity. The technique allows to measure a volume fraction of recrystallized grains and its grain size distribution for the different grain orientations (in accordingly to a number of X-ray reflexes under measurement). It permits to assess the actually texture formation mode for the recrystallization process. The application of the [[omega]]-scanning method for development of the production technology of the textured Ti parts is demonstrated in the present paper. The dynamic and static recrystallization behaviour of a commercial grade Ti is studied on the basis of texture mode changes during industrial processing steps. The damage accumulation under loading in form subgrain fragmentation is obtainable from the [[omega]]-scanning patterns for structural materials which are used in recrystallized state, such as Ni-superalloys. On this base the non-destructive method of residual lifetime forecast was proposed for the aircraft engine discs. A volume fraction of a precipitated phase in recrystallized matrix also can be estimated from the [[omega]]-scanning patterns, for example a fraction of the [[gamma]]'-phase in the Ni-superalloys.