crude niobium. The phase composition of sublimates formed during the first remelting of crude niobium is studied by scanning electron microscopy and X-ray microanalysis. Sublimates typically form structures of two types, i.e., dendritic and lamellar that is connected with niobium refining process conditions and the effect of various factors on sublimate crystallization. Niobium electron beam remelting sublimates are inconsistent with respect to both chemical and phase compositions. A layered structure is typical for the porous part of sublimates that are the basis of the material. The microstructure of another type is dendritic, typical for lamellar and rounded particles with a metallic sheen located within pores or dispersed in the layered part of sublimates. Alternation of phases within each layer is noted for a layered structure. The composition of the phases containing niobium is close to NbAl3 and a solid solution based on niobium (more than 90% Nb). Within the zone of phases consisting of aluminum, there are areas accumulating iron and silicon of variable composition that may be attributed to solid solutions based on Al5FeSi and Al3Fe. The structure of the metallized part of the sublimates consists of light rounded dendrites of niobium aluminide NbAl3, between which there is a phase close in composition to Al8Fe2Si. It is noted that single particles of pure niobium metal are found within the structure of the metallized part of sublimates. It is noted that as expected the main phase is NbAl3 intermetallic. Niobium is also present in the form of silicide Nb5Si3. Aluminum is found in sublimates in elemental form, in solid solution with iron and silicon, or in the form of oxide. Impurity elements are distributed between an oxide phase based on α –Al2O3 (Fe, Si, Ni) and Al–Fe–Si (Cr, Mn, Ni) solid solution.

中文翻译：

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粗铌电子束重熔升华物的显微组织和相组成研究

粗铌。通过扫描电子显微镜和 X 射线显微分析研究了粗铌第一次重熔过程中形成的升华物的相组成。升华物通常形成两种类型的结构，即树枝状和层状，这与铌精炼工艺条件和各种因素对升华结晶的影响有关。铌电子束重熔升华物在化学和相组成方面都不一致。层状结构对于作为材料基础的升华物的多孔部分是典型的。另一种类型的微观结构是树枝状的，典型的是层状和圆形颗粒，具有金属光泽，位于孔内或分散在升华物的层状部分。对于分层结构，注意到每一层内的相交替。含铌相的组成接近 NbAl3 和基于铌的固溶体（超过 90% Nb）。在由铝组成的相区中，有一些区域积累了不同成分的铁和硅，这可能归因于基于 Al5FeSi 和 Al3Fe 的固溶体。升华物的金属化部分的结构由铌铝化铌 NbAl3 的轻圆形枝晶组成，其间有一个组成接近 Al8Fe2Si 的相。注意到在升华物的金属化部分的结构中发现了纯铌金属的单个颗粒。值得注意的是，正如预期的那样，主相是 NbAl3 金属间化合物。铌也以硅化物 Nb5Si3 的形式存在。铝以元素形式存在于升华物中，与铁和硅的固溶体中，或以氧化物的形式。杂质元素分布在基于α-Al2O3（Fe、Si、Ni）和Al-Fe-Si（Cr、Mn、Ni）固溶体的氧化物相之间。