Effective grain pinning revealed by nanoscale electron tomography

TitleEffective grain pinning revealed by nanoscale electron tomography
Publication TypeJournal Article
Year of Publication2011
AuthorsWu YQ, Tang W, Dennis KW, Oster N, McCallum RW, Anderson IE, Kramer MJ
Journal TitleJournal of Applied Physics
Date Published04/01
Type of ArticleProceedings Paper
ISBN Number0021-8979
Accession NumberISI:000289949000223
KeywordsADDITIONS, magnetic-properties, melt-spun ribbons, microstructure

The grain pinning behavior of TiC particles in a rapidly solidified MRE-Fe-B (MRE = Nd + Y + Dy) nanocrystalline hard magnet was studied using electron tomography (ET). The 3D reconstruction overcomes the inherent 2D nature of conventional transmission electron microscopy (TEM) to reveal how this grain boundary phase controls the nanoscale structure in the rapidly solidified alloy. The 3D reconstruction was performed on the optimally annealed alloy (750 degrees C/15 min) with hard magnetic properties of M-r = 8.1 kGs, H-c = 6.2 kOe, (BH)(max) = 11.2 MGOe measured at 300 k. The sampled volume, 425 x 425 x 92.5 nm(3), contains more than 20 grains of the RE2-14-1 phase and more than 70 TiC nanoparticles. The TiC grains' shapes depend on their sizes and locations along the grain boundary. Most of the TiC particles are oval or short rod like shapes and range from 5 nm to 10 nm. TiC particles less than 10 nm formed between adjacent 2-14-1 grains, while the largest ones formed at triple junctions. There are similar to 1.7 x 10(8) TiC particles within a 1 mm(3) volume in the alloy. This accounts for the strong grain boundary pinning effect, which limits grain growth during annealing. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3549603]

URL<Go to ISI>://000289949000223
Alternate JournalJ. Appl. Phys.