In a typical sintered multi-component SmCo-type magnet with strong fiber texture, we show that the distributions of grain boundary precipitates (GBPs) are heavily dependent on the grain boundary (GB) geometry with respect to the texture direction, which has significant effects on domain wall pinning. Results demonstrate that the continuous GBPs turn into discrete upon the angle between {0001} planes and GB increases from 0° to 90°, meanwhile the GBPs thickness and precipitation free zones (PFZs) width both increase linearly by a factor of 2.5–4. Transmission electron microscopy (TEM) reveals that the GBPs are alternatively stacked Cu-rich SmCo and Zr-rich SmCo ( = 2,3,4) compounds, while the PFZs are composed of 2:17R and intermediate 2:17R’ phases. Atomic-level elemental mappings and first-principles calculations indicate that Cu exists at the Co-2c site in the SmCo forming SmCoCu and Zr locates at the dumbbell Sm-6c sites in the SmCo. The symbiotic GBPs have orientation relationships of [0001]//[0001] and [100]//[20]. The formation of anisotropic GBPs is owing to the strong fiber texture, i.e., the larger angle between {0001} planes and GBs, the more {0001} diffusion channels for atoms to GBs, resulting in discrete and thick GBPs. In-situ Lorentz TEM shows that the domain walls interrupted by GBPs migrate easily under applied magnetic fields. Possible approaches to enhance the magnetic hardness via tuning the GBs are proposed.

中文翻译：

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烧结 Sm2Co17 型磁体中取向相关的晶界析出物分布和磁畴壁钉扎效应减弱


在具有强纤维织构的典型烧结多组分钐钴型磁体中，我们发现晶界析出物（GBP）的分布很大程度上取决于相对于织构方向的晶界（GB）几何形状，这具有显着的影响在域壁钉扎上。结果表明，当{0001}面与GB之间的角度从0°增加到90°时，连续GBP变成离散的，同时GBP厚度和无降水区（PFZ）宽度均线性增加2.5-4倍。透射电子显微镜（TEM）显示GBP是交替堆叠的富Cu SmCo和富Zr SmCo（= 2,3,4）化合物，而PFZ由2:17R和中间2:17R'相组成。原子级元素图谱和第一性原理计算表明，Cu存在于SmCo中的Co-2c位点，形成SmCoCu，而Zr位于SmCo中的哑铃型Sm-6c位点。共生GBP具有[0001]//[0001]和[100]//[20]的取向关系。各向异性GBP的形成是由于强纤维织构，即{0001}平面与GB之间的角度越大，原子到GBP的{0001}扩散通道就越多，从而导致离散且厚的GBP。原位洛伦兹 TEM 显示，被 GBP 中断的磁畴壁在施加的磁场下很容易迁移。提出了通过调整 GB 来提高磁硬度的可能方法。