体心立方金属铌中小角度晶界分解的原位电子显微学表征

Study on the elimination of low-angle grain boundaries in body-centered cubic niobium

本文利用像差校正透射电子显微镜研究了体心立方金属铌中的小角度晶界,并结合原位拉伸实验技术对其在拉伸加载过程中的变形行为进行观察。结果表明,在铌金属中的小角度晶界为非对称倾转晶界,由1/2[111]和1/2[111]两种类型的全位错构成。加载过程中该小角度晶界上的位错向外滑移,并最终导致了小角度晶界的分解消失。

Low-angle grain boundaries in the body-centered cubic structured Nb and the elimination of these grain boundaries were investigated by using in situ aberration-corrected electron microscopy. It is found that these grain boundaries are asymmetrical tilt low-angle grain boundaries, which consist of 1/2[-111] and 1/2[11-1] dislocations. The elimination of low-angle grain boundaries can take place due to the glide of these dislocations away from the boundaries under tensile loading.