Structure and properties of the permanent magnet alloys

IT IS AN OLD NOTION that high coercivity in ferromagnetic materials is associated with high internal stresses. Cold working, quench hardening, and precipitation hardening have been known or suspected sources of residual stresses and they have been generally found to be responsible for increased coercive force. However, no quantitative correlation has yet been possible since the stresses or their counterpart, the reaction strains, have only recently been identified in a specific manner.