Title :
Basic study for plastic deformation of rapidly quenched Nd-Fe-Co-Ga-B magnets at elevated temperature
Author :
Akayama, M. ; Tanigawa, S. ; Tokunaga, M.
Author_Institution :
Hitachi Metals Ltd., Saitama, Japan
fDate :
9/1/1990 12:00:00 AM
Abstract :
In order to optimize hot-working conditions of rapidly quenched Nd-Fe-Co-Ga-B magnets, the behavior of plastic deformation at elevated temperatures has been studied. Compressive and tensile tests were performed with various hot-working parameters. From compression tests, a strain-rate sensitivity factor and a strain hardening factor at 700°C of 0.4 and 0.3, respectively, were obtained. From tensile tests, the tensile strength and elongation at 700°C were determined to be 1.0~1.8 kgf/mm2 and 6~12%, respectively. Based on these data, computer simulation of the die upsetting process was performed by rigid plastic FEM (finite-element method) calculation. It was found that, to suppress the occurrence of peripheral cracks and improve magnetic properties, low strain rates are necessary. Computer calculation of the stress distribution can explain the mechanism of peripheral crack initiation in the die upsetting process
Keywords :
boron alloys; cobalt alloys; cracks; finite element analysis; gallium alloys; hot working; iron alloys; neodymium alloys; plastic deformation; quenching (thermal); tensile strength; work hardening; 700 degC; Nd-Fe-Co-Ga-B magnets; compression tests; computer simulation; die upsetting; elevated temperature; elongation; finite-element method; hot-working conditions; magnetic properties; peripheral cracks; plastic deformation; rapidly quenched; rigid plastic FEM; strain hardening factor; strain-rate sensitivity factor; stress distribution; tensile strength; tensile tests; Computer peripherals; Computer simulation; Finite element methods; Magnetic field induced strain; Magnetic properties; Magnets; Performance evaluation; Plastics; Temperature sensors; Testing;
Journal_Title :
Magnetics, IEEE Transactions on
