Grain orientations and grain boundary migrations near triple junctions in a high purity aluminum were analyzed by electron backscattered diffraction (EBSD). The results indicate that good correlations exist between the Schmid factors and Taylor factors and misorientation values of the point in grains near triple junctions in deformed samples to the original point. Grains with higher Schmid factors or lower Taylor factors typically correspond to higher misorientation values near the triple junctions. The largest misori-entation increases with the increasing degree of deformation. In subsequent annealing at 400 ?C for 15 min, both grain boundaries and triple junctions migrate, and the former leaves ghost lines. During such migration, in general, a grain boundary grows from the grain with a lower Schmid factor into that with a higher Schmid factor, that is, a hard crystal grows into an adjacent soft crystal. Usually, the amount of migration of a grain boundary is considerably greater than that of a triple junction in light deformation, and the grain boundary becomes more curved after migration. The grain boundary migrates further during the second annealing at 400 ?C for 17 min to reduce the residual strain energy.%采用电子背散射衍射(electron backscattered diffraction,EBSD)技术研究了不同变形量高纯铝试样的变形行为和退火后三叉晶界及晶界的迁移行为.研究结果表明,冷轧变形后三叉晶界附近的点对原点的取向差与泰勒因子及施密特因子有很好的一致性.具有较大施密特因子或者较小泰勒因子的晶粒的取向差较大,并且随着变形量的增大取向差的最大值也增大.Kernel平均取向差(Kernel average misorientation,KAM)图表明塑性变形时,三叉晶界和晶界处应变集中.对于冷轧变形量为17%的三叉晶界,施密特因子最大的晶粒内部滑移带终止于晶内,主要原因是相邻晶粒变形时为了相互协调,晶界附近的晶粒间发生了较大偏转,出现了晶界影响区外;对于变形量为35%的三叉晶界,除了出现晶界影响区外,在施密特因子最大的晶粒内三叉结附近出现了折痕.随后试样经过第一次400?C退火15 min,三叉晶界及其相关晶界发生了迁移,并且晶界在原来的位置留下了鬼线.晶界都是由施密特因子较小的晶粒向施密特因子较大的晶粒迁移,也就是由硬取向的晶粒向软取向的晶粒迁移,并且迁移后晶界变得更弯曲,晶界的迁移距离比三叉结的大,说明在此温度下退火后,三叉结对晶界的迁移有拖曳作用.三叉晶界及其晶界的迁移量随着变形量的增大而增大,这是因为变形量大、储能高,给三叉晶界及晶界提供的驱动力也大.最后试样经过第二次400?C退火17 min,为了降低第一次退火后残留的应变能,晶界又进一步迁移.
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