14 m-2下降到4.2×1013 m-2，大角度晶界含量從63.8%增加到70.8%，使得位錯(cuò)湮滅速率提升，從而導(dǎo)致了應(yīng)變硬化能力的降低。在90~210 ℃的強(qiáng)磁場退火條件下，低含量的大角度晶界（61.7%~66.2%）可以提供一個(gè)較慢的位錯(cuò)湮滅速率，從而導(dǎo)致較高的均勻延伸率（0.64%~1.60%）和更慢的屈服點(diǎn)后的流變應(yīng)力下降。;The ultrafine grained (UFG) 1050 aluminum alloy was prepared by equal channel angular pressing at cryogenic temperature, namely cryoECAP process. The tensile behavior and microstructures of UFG 1050 aluminum alloy after annealing at 90–210 °C for 4 h without and with high magnetic field of 12 T were investigated by tensile tests, transmission electron microscope, and electron backscattered diffraction analyses. After cryoECAP and annealing treatments, the 1050 aluminum alloy has ultrafine grains with 0.7–1.28 μm in size, the ratio of ultimate tensile strength to yield strength is less than 1.24, and the uniform elongation is less than 2.3%. With increasing the annealing temperature from 90 °C to 210 °C, the yield-drop phenomenon becomes more obvious due to the decrease in mobile dislocations to maintain the applied strain rate during tensile deformation. The uniform elongation decreases from 1.55% to 0.55%, the dislocation density reduces from 5.6×1014 m-2 to 4.2×1013 m-2, and the fraction of high-angle grain boundaries (HABs) increases from 63.8% to 70.8%. These phenomena cause the higher annihilation rate of dislocations, thereby leading to the degradation of strain hardening effect. During annealing under high magnetic field at 90–210 °C, the low fraction of HABs (61.7%–66.2%) can provide a slower annihilation rate of dislocations, therefore resulting in the higher uniform elongation (0.64%–1.60%) and slower decrease in the flow stress after the yield peak."/>