Abstract

X-ray diffraction analysis, scanning electron microscopy, and atomic force microscopy are used to study the phase composition, texture, and peculiarities of the morphology of R–Fe–B (R = Nd, Pr, Dy) alloys prepared by strip-casting technology. Along with the traditional structural components of the alloys, namely, areas characterized by randomly oriented fine grains of the main magnetic phase with the Nd₂Fe₁₄B-type structure (which are formed near the contact surface of flakes) and coarse extended textured grains of the phase (in the volume of flakes), wide areas characterized by uniform distribution of rare-earth metal-rich phase with a period of 2–4 µm were also found. The formation of these areas takes place in the absence of coarse dendritic crystallites and, according to the suggested mechanism, is related to the solidification of the melt under conditions of its motion upon quenching on a cooled cylindrical surface. Data indicating the melt twisting upon solidification, which favors the formation of the structure with the aforementioned distribution of intergranular phase, are reported. The data obtained are discussed from the viewpoint of their practical utility for the improvement of the structure of alloys prepared by strip-casting and powders for manufacturing Nd–Fe–B permanent magnets.

中文翻译：

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R-Fe-B（R = Nd，Pr）合金通过流延铸造凝固后形成的形貌特征

摘要

X射线衍射分析，扫描电子显微镜和原子力显微镜用于研究通过铸带法制备的R–Fe–B（R = Nd，Pr，Dy）合金的相组成，织构和特性。技术。与合金的传统结构成分一起，即具有以Nd ₂ Fe ₁₄主磁相随机取向的细晶粒为特征的区域B型结构（在薄片的接触表面附近形成）和该相的粗大延伸纹理晶粒（在薄片的体积中），宽阔的区域具有均匀分布的稀土金属富集相，周期为2还发现了–4 µm。这些区域的形成是在不存在粗大的树枝状微晶的情况下发生的，并且根据建议的机理，与在冷却的圆柱形表面上淬火时在其运动的条件下熔体的凝固有关。报道了表明凝固时熔体扭曲的数据，其有利于形成具有上述晶间相分布的结构。