Mechanical properties of Fe-Co soft magnets

The tensile behavior of two magnetically soft alloys, Fe-49Co-2V and Fe-27C o, has been characterized as a function of testing temperature, grain size, and degree of long-range order. Several trends in the yield strength of th e two alloys have been noted and possible mechanisms for their occurrence d iscussed. Ordering is found to markedly lower the yield strength of the Fe- 49Co-2V. Both alloys exhibit three distinct regions in their yield strength vs. temperature curves. At lower and higher temperatures, i.e. regions I a nd III, the yield strength shows the normal drop with increasing temperatur e. In the intermediate temperature range (region II), however, Fe-49Co-2V w ith a B2 ordered structure demonstrates an anomalous strengthening with inc reasing temperature while the yield strength remains constant in the disord ered Fe-27Co. Both alloys exhibit a Hall-Petch type relationship in their y ield strength as a function of grain size and show a decrease in the strain hardening coefficient with increasing grain size. (C) 2001 Kluwer Academic Publishers.