Texture and Cleavage in Molybdenum

It is of considerable technological importance to establish how far textures introducedinto controlled-rolled steels by finish rolling at low temperatures may affect the fracturestrength. The purely textural effect is difficult to isolate in such steels because of anisotropyassociated with grain shape, inclusions and pearlite banding. Consequently, an investigationwas carried out using molybdenum, a b.c.c. single phase material showing goodstructural homogeneity, as a model. Texture development was studied using crystalliteorientation distribution function analysis to identify a suitable processing route leadingto a sharp texture with a suitable distribution of {100} cleavage planes. The behaviourof a sharply textured specimen was analysed by taking fracture specimens from variousorientations in the plate. The energy absorbed in impact showed a positive correlationwith the density of 100 planes in the crack direction, but the extent of the variation wasless than would have been expected had crack propagation been the controlling step inthe fracture process.