High-entropy alloys (HEAs) open up a new horizon for discovering un-explored mechanical properties and deformation mechanisms. Local chemical fluctuations (LCFs) in HEAs were found to have significant influences on their mechanical performance, however, the underlying origins remain unclear. In this work, direct dynamic observation of the interaction between LCFs and dislocations was captured by in situ transmission electron microscopy in a ductile body-centered-cubic (BCC) HfNbTiZr HEA under loading. The observed dislocation pinning induced by LCFs contributes to the increment not only in the strength but also in the ductility due to strongly promoted dislocation interaction. The observed local double cross-slips caused by the LCFs distribute dislocations onto various atomic planes homogenously, which is also beneficial for ductilization in HfNbTiZr. Our findings not only shed light on the understanding of deformation mechanisms of HEAs, but also provide a new perspective to design ductile BCC HEAs.

高熵合金 (HEAs) 为发现未探索的机械性能和变形机制开辟了新的视野。发现 HEA 中的局部化学波动 (LCF) 对其机械性能有显着影响，然而，潜在的起源仍不清楚。在这项工作中，通过原位捕获 LCF 和位错之间相互作用的直接动态观察载荷下延展性体心立方 (BCC) HfNbTiZr HEA 中的透射电子显微镜。由于强烈促进的位错相互作用，观察到的由 LCF 引起的位错钉扎不仅有助于强度的增加，而且有助于延展性的增加。观察到的由 LCF 引起的局部双交叉滑移将位错均匀地分布在各个原子平面上，这也有利于 HfNbTiZr 的延展性。我们的发现不仅阐明了对 HEA 变形机制的理解，而且为设计延性 BCC HEA 提供了新的视角。