Planar superstructure defects (PSDs) have a great influence on the mechanical and functional properties of ternary Heusler alloys, but a complete analysis of their structure and energy is lacking in the literature. In this work, for Heusler alloys of stoichiometric composition X₂YZ, having the L2₁ superstructure, expressions are given for calculating the sublimation energy and the energy of an arbitrary PSD under the assumption of hard coordination spheres and pair interatomic interactions. It is shown that for a given crystallographic orientation there cannot be more than three PSDs with different energies. An expression is given for finding the planes of occurrence of all possible conservative antiphase boundaries (APBs). It is established that in Heusler alloys there are only conservative and nonconservative APBs and there are no defects such as boundaries of C-domains or inversion APBs. The results obtained are useful for the analysis of slip systems and the configuration of magnetic domain walls of the considered family of alloys.

平面超结构缺陷（PSDs）对三元赫斯勒合金的机械和功能性能有很大影响，但文献中缺乏对其结构和能量的完整分析。在这项工作中，对于化学计量组成X ₂ YZ 的Heusler 合金，具有L 2 ₁在上层结构中，给出了在硬配位球和对原子间相互作用的假设下计算升华能量和任意 PSD 能量的表达式。结果表明，对于给定的晶体取向，具有不同能量的 PSD 不能超过三个。给出了用于找到所有可能的保守反相边界 (APB) 出现平面的表达式。已经确定，在 Heusler 合金中，只有保守和非保守 APB，并且不存在C域边界或反转 APB等缺陷。获得的结果可用于分析滑移系统和所考虑合金系列的磁畴壁配置。