Open AccessBrittle fracture in Nd{sub 2}Fe{sub 14}B intermetallic magnets
Author(s) -
Joseph A. Horton,
L. Heatherly,
E. D. Specht,
D. Li,
J. W. Herchenroeder,
P. C. Canfield
Publication year - 1998
Language(s) - English
Resource type - Reports
DOI - 10.2172/650388
Subject(s) - cleavage (geology) , intermetallic , materials science , grain boundary , neodymium , eutectic system , crystallography , auger electron spectroscopy , fracture toughness , brittleness , scanning electron microscope , magnet , metallurgy , fracture (geology) , composite material , alloy , microstructure , chemistry , optics , physics , quantum mechanics , nuclear physics , laser
Efforts to understand and improve the fracture toughness of Nd{sub 2}Fe{sub 14}B permanent magnets require an understanding of the fracture process itself. Cleavage plane orientations in Nd{sub 2}Fe{sub 14}B were identified by X-ray diffraction and found to be rather random. Cleavage fracture surfaces often exhibited smooth curvatures with no evidence for cleavage steps. The small grain sizes of less than 100 nm in Magnequench MQ material preclude an easy assessment of the fracture mode by scanning electron microscopy. Auger electron spectroscopy showed that much of the surface is covered with a 1 nm thick layer of a neodymium-rich phase presumably the 70Nd-30Fe eutectic phase suggesting that the hard Nd{sub 2}Fe{sub 14}B grains do not cleave but instead failure is at or in the grain boundary phase