A generalized solidification model and microstructural verification for the Nd–Fe–B–Ti–C system processed by rapid solidification

Authors

Matthew J. Kramer, Iowa State UniversityFollow
C.P. Li, Iowa State University, Ames, Iowa
K.W. Dennis, Iowa State University, Ames, Iowa
R.W. McCallum, Iowa State University, Ames, Iowa
C.H. Sellers, Lockheed Martin Idaho Technologies, Idaho National Engineering Laboratory, Idaho Falls, Idaho
D.J. Branagan, Lockheed Martin Idaho Technologies, Idaho National Engineering Laboratory, Idaho Falls, Idaho
Jeffrey E. Shield, Iowa State UniversityFollow

Date of this Version

4-15-1997

Comments

Published in J. Appl. Phys. 81 (8), 15 April 1997. © 1997 American Institute of Physics. Used by permission.

Abstract

For the Nd₂Fe₁₄B (2-14-1) compound, the optimal grain size should be smaller than the size of the single domain size of 150 nm. Transition metal carbides (TMC) also reduce the quench rate necessary to achieve the optimal or overquenched condition. This allows inert gas atomization (IGA) to produce viable magnetic materials. In this article we will demonstrate that optimal microstructure for the 2-14-1 can be produced by IGA with the addition of TiC. Moreover, a solidification model will be presented to show (1) how recalescence is a critical feature to the evolution of the microstructure in rapidly solidified materials and (2) the role TMC and other solute phases have on inhibiting grain growth so that lower quench rates can be employed.