论文信息 - Microstructure of aged (Co,Cu,Fe)7Sm magnets

Microstructure of aged (Co,Cu,Fe)7Sm magnets

The microstructure of (Co,Cu,Fe)7Sm magnets has been characterized at various states of aging by transmission electron microscopy. At peak magnet properties, the magnet consists of cells of 17 : 2 phase about 500 A in diameter, separated by a thin continuous fully coherent 5 : 1 boundary phase. This structure evolved by precipitation of ordered 17 : 2 particles from a disordered 5 : 1 matrix, and coarsens with aging until full coherence is lost and the cellular structure breaks up. The overaged alloy consists of semicoherent 5 : 1 particles in a 17 : 2 matrix, with a single set of interface dislocations accommodating the lattice mismatch. The effect of these various microstructural changes on domain‐wall pinning and coercivity is discussed.

J. Livingston | D. Martin | D. L. Martin | J. D. Livingston

[1] A. Menth,et al. Bulk‐hardened Sm‐Co‐Cu‐Fe 2:17 magnets , 1976 .

[2] J. Livingston,et al. Domain‐wall energy in cobalt‐rare‐earth compounds , 1972 .

[3] H. Leamy,et al. The structure of Co-Cu-Fe-Ce permanent magnets , 1973 .

[4] Discontinuous coarsening of aligned eutectoids , 1974 .

[5] J. Bernasconi,et al. Magnetic properties of Sm(Co,Cu) alloys. II. Coercivity mechanism , 1976 .

[6] A. Ardell,et al. The coarsening of γ' precipitates at large volume fractions , 1974 .

[7] Y. Tawara,et al. Magnetic Properties of Sm-Co-Fe-Cu Alloys for Permanent Magnet Materials , 1975 .

[8] H. Kronmüller,et al. Incoherent nucleation of reversed domains in Co5Sm permanent magnets , 1975 .

[9] J. Livingston. Domains in sintered Co‐Cu‐Fe‐Sm magnets , 1975 .

[10] D. Martin,et al. Phase stability of Co 5 Sm , 1974 .

[11] P. Haasen. Mechanical, magnetic and superconductor hardening by precipitates , 1972 .

[12] K. Melton,et al. Magnetic properties of Sm : (Co,Cu) alloys. I. Electron microscopy , 1976 .

[13] H. Kronmüller,et al. Statistical theory of the pinning of Bloch walls by randomly distributed defects , 1975 .

[14] K. Buschow,et al. Intermetallic compounds in the system samarium-cobalt , 1968 .