Influences of magnetic annealing on the grain growth in a cryoECAPed 1050 aluminum alloy

The evolutions of hardness, grain microstructures and dislocations were investigated in cryoECAPed 1050 aluminum alloy after annealing at 423-673 K for 1 h without and with a magnetic field of 12 T. Compared to those of samples annealed without the magnetic field, the hardness of samples annealed with the magnetic field is lower at 423-573 K, and then higher at > 573 K. The high magnetic field accelerates the formation of dislocation cells or sub-grains. The interface dislocations frequently observed in materials deformed at high temperature were detected in samples annealed with the magnetic field at ≥ 423 K. The fraction of low angle boundaries in sample annealed with the field is 49% and 34% in sample annealed without the field even at 673 K. No abnormal grain growth occurs in samples annealed with the magnetic field due to the rapid consumption of the stored distortion energy during recovery.