Microstructure and Property Evolution in Cold Worked Equiatomic Fe-Pd During Isothermal Annealing.
In this work the evolution of microstructure and magnetic properties in cold deformed, equiatomic FePd during isothermal annealing has been studied. During annealing of the disordered cold deformed FePd at temperatures below the critical ordering temperature, Tc = 928 K (655 ºC), concomitant annealing and ordering (FCC -> L1sub0) reactions take place. The effects of the processing parameters - stored energy of cold work and temperature - on microstructural and property evolution are investigated. The combined solid state reaction (CR) produces complex microstructures that exhibit enhanced magnetic hardness (coercivity) relative to the conventionally processed material. The magnetic age hardening response of the CR processed FePd has been reported. For fully equiaxed polycrystalline microstructures of the ordered FePd phase a correlation between the average grain size and the coercivity has been observed. Based on these purely microstructural observations a qualitative coercivity mechanism analysis has been performed in order to elucidate the origin of the decrease in magnetic hardness (coercivity) in the overaged condition.
Advisor:Dr.J.A. Barnard; Dr W.A. Soffa; Dr Jorg.M.K. Wiezorek
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Keywords:materials science and engineering
Date of Publication:06/09/2004