Large relrod extension induced by lattice distortion in high entropy alloy

As a fundamental concept, lattice distortion is one of the four core effects in high entropy alloys (HEAs). However, there were few experimental evidences that directly observed the lattice distortion in HEAs. In this work, the experimental observation of lattice distortion in a new developed Fe(33)Mn(13)Co(22)Cr(15)Ni(17)HEA by multiple tilting selected area electron diffraction (SAED) was reported. SAED observation of 51 zone axes were performed in a single grain of the HEA sample. Among them, 24 normal diffraction patterns and 27 anomalous diffraction patterns with extra diffraction spots around the normal reflection spots were observed. According to the proportional relationship between the extra diffraction spots and the normal ones, the extra diffraction spots could be indexed with three non-integral Miller indices. The anomalous diffraction patterns were considered as the effect of reciprocal space lattice distortion, resulting in a relrod extension on the order of half of the reciprocal space lattice constant. The existence of numerous extended reciprocal relrod suggested that serious lattice distortion occurred in concerned HEA, and it significantly affected the transformation from direct lattice to reciprocal lattice.