RECRYSTALLIZATION AND GRAIN-GROWTH PHENOMENA IN A PARTICLE-REINFORCEDALUMINUM COMPOSITE

Recrystallization and grain growth in a 2219/TiC/15p composite were in vestigated as functions of the amount of deformation and deformation t emperature. Both cold and hot deformed samples were annealed at the no rmal solution treatment temperature of 535 degrees C. It was shown tha t large recrystallized grain diameters, relative to the interparticle spacing, could be produced in a narrow range of deformation for sample s cold-worked and those hot-worked below 450 degrees C. For cold-worke d samples, between 4 to 6 pet deformation, the recrystallized grain di ameters varied from 530 to 66 mu m as the amount of deformation increa sed. Subsequent grain growth was not observed in these recrystallized materials and noncompact grain shapes were observed. For deformations greater than 15 pet, recrystallized grain diameters less than the inte rparticle spacing were observed and subsequent grain growth produced a pinned grain diameter of 27 mu m. The pinned grain diameter agreed we ll with an empirical model based on three dimensional (3-D) Monte Carl o simulations of grain growth and particle pinning in a two-phase mate rial. Tensile properties were determined as a function of grain size, and it was shown that grain size had a weak influence on yield strengt h. A maximum in the yield strength was observed at a grain size larger than the normal grain growth and particle-pinned diameter.