Abstract: The 99.99% high purity copper target was hot rolled at 600 ℃ with 55% deformation and annealed at 280, 300 and 320 ℃ for 2 h, respectively. The evolution of grain size, orientation distribution and twins of the high purity copper target at different annealing temperatures were studied by EBSD technique. The results show that the large grains in the copper target are fully broken by rolled at 600 ℃. The annealing at 320 ℃ leads to more uniform grains and less twin content by 14% than that at 280 ℃. The <311> orientation of the high purity copper target can form easily during rolling, and tends to decrease when the annealing temperature rising from 280 ℃ to 320 ℃, while the<110> orientation tends to increase. Therefore, the 320 ℃ annealing temperature is beneficial to obtain uniform and fine grains, a lower twin content and uniform orientation distribution.

Key words: high purity copper target, microstructure, grain size, texture, twin