Abstract The peculiarities of microstructure of nanocrystalline powders of nonstoichiometric niobium carbides have been generalized in all homogeneity interval of cubic NbCy phase. Nanocrystalline NbCy powders were produced by high-energy milling of coarse-crystalline powders. For the first time, it is established that the microstructure of nanocrystalline NbCy powders is an inhomogeneous, and contains two cubic fractions differing by particle size and carbon content. Fine details of an inhomogeneous microstructure of NbCy nanopowders have been determined by the time-of-flight neutron high resolution Fourier diffractometry. The analysis of the neutron diffraction data revealed microstrain anisotropy in the nanopowders. The average sizes of the coherent scattering regions and microstrains in nanocrystallites with allowance for the anisotropy of the deformation distortions have been estimated. The consideration of the anisotropy of elastic properties has shown that the splitting of niobium carbide particles during high-energy milling is likely to take place in the (110) or (111) planes in the directions where the shear modulus has the least value.

中文翻译：

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碳化铌纳米粉体微观结构的各向异性和弹性性能

摘要 非化学计量比的碳化铌纳米晶粉末的显微结构特征已在立方NbCy相的所有均质区间中得到推广。纳米晶 NbCy 粉末是通过高能研磨粗晶粉末制备的。首次确定纳米晶 NbCy 粉末的微观结构是不均匀的，并且包含两种不同粒径和碳含量的立方部分。NbCy 纳米粉末的不均匀微观结构的精细细节已通过飞行时间中子高分辨率傅里叶衍射法确定。中子衍射数据的分析揭示了纳米粉末中的微应变各向异性。已经估计了纳米微晶中相干散射区域和微应变的平均尺寸，并考虑了变形畸变的各向异性。对弹性性能各向异性的考虑表明，高能球磨过程中碳化铌颗粒的分裂很可能发生在（110）或（111）面中剪切模量最小的方向。