Effects of annealing treatment on the microstructure evolution and the strength degradation behavior of the commercially pure Al conductor

Strength degradation during the electron transmission process is always a hidden danger to the overhead transmission lines. In this study, the microstructure evolutions and the strength degradation behaviors of a cold-drawn commercially pure Al conductor (CPAC) were investigated systematically by a series of annealing experiments. The results show that the texture evolution, dislocation recovery and subgrain growth during the recrystallization should be responsible for the strength degradation of CPAC. Besides, the microstructure evolution depends on the annealing temperature. For instance, some of the <111> texture was changed into the <001> one in the CPACs annealed at a temperature of 90 °C; while, there is an obvious increase in the subgrain width when the CPACs were annealed in the high temperature range from 150 °C to 300 °C. Finally, the strength degradation due to the texture evolution and the subgrain coarsening was quantitatively calculated based on the crystallographic analysis.