Abstract: Microstructure and mechanical properties of T2 pure copper annealed with different processes were studied by using OM, SEM and tensile tests. The results show that the increase of annealing temperature and the extension of annealing time lead to increase in the content of recrystallized structure and annealing twin in the microstructure of the pure copper, thereby enhancing the plasticity of annealed pure copper. After annealing at 150 ℃ for 60 min, the pure copper achieves room temperature tensile strength of 309.1 MPa and elongation after fracture of 16.7% under the multiple effects of grain boundary strengthening, dislocation strengthening and twinning. Compared with the original pure copper, the room temperature tensile strength increases by 11.6% and the elongation increases by 34.7%. According to the tensile test at high temperature, the pure copper exhibits excellent thermal stability after annealing at 100 ℃ for 30 min.

Key words: pure copper, annealing treatment, microstructure, mechanical properties, thermal stability