Microstructural evolution of ECAPed 1050 alloy under magnetic annealing

Hardness and microstructure evolutions in 1050 aluminum alloy prepared by equal-channel angular pressing (ECAP) were investigated by hardness testing, optical microscopy, and transmission electron microscopy after samples were annealed at different temperatures for 1 h both in the absence and presence of a 12-T magnetic field. The results showed that the hardness of samples after magnetic annealing were lower than that of samples after normal annealing at 150–250°C, but it was higher than that of samples after normal annealing at >250°C. During annealing, the rate of softening was faster, and the grains were more homogeneous in 8-ECAPed samples than in 2-ECAPed samples. A rapid grain growth occurred when 2-ECAPed samples were annealed at high temperature (≥300°C). The magnetic field enhanced the mobility of dislocations and grain boundaries. A more homogeneous grain size was observed in samples prepared under an applied magnetic field.