Grain growth texture evolution in zirconium (Zr702) and commercially pure titanium (T40)

Primary recrystallization of a 80% cold-rolled T40 or Zr702 sheets leads to equiaxed microstructures. Subsequently, only normal grain growth takes place in T40 while a few grains can grow abnormally after sufficient time at high annealing temperature (close to the transus) in Zr702. The grain sizes reached after extended grain growth at moderate temperatures in Zr702 are smaller than in T40. The presence of precipitates in Zr702 is probably responsible for this and also for the abnormal phenomena observed at high temperature in this material. The texture changes occurring in both materials under normal grain growth conditions (often roughly described as "30degrees rotation around c axes") are due to the development of the largest gains produced by the primary recrystallization. These large grains are preferentially oriented around {phi(1)=0degrees, Phi=30degrees, phi(2)=30degrees} for T40 and around {phi(1)=0degrees, Phi=25degrees, phi(2)=30degrees} for Zr702, orientations which become predominant after extended grain growth.