| This thesis focus on the research of Fe-25Cr-12Co and Fe-25Cr-5Co alloys fabricated by directional solidification and heat treatment under high magnetic field.The microstructure of alloy under directional solidification,magnetic flux density,and annealing temperature have been studied to find out its relations with alloy performance.The increasement of drawing speed of directional solidification is benefit to decrease the precipitation of a phase,but a drawing speed too large is harmful to the directional regular arrangement of microstructure.The increasement of drawing speed is benefit to the decrease the dendrite distance of Fe-25Cr-5Co alloys,and a very large drawing disturb the directional regular arrangement of dendrites.The annealing of alloy under magnetic field is benefit to the transformation of ?1 particles to long rod shape,and retain this shape during a long speriod of tempering process.The shape of ?1 particles turns to be long and slim with increasing magnetic flux density.1T magnetic field does not change the the perentage of ?1 phase significantly,but strength field such like 12T decrease the percentage of ?1 particles.Under all the annealing and tempering conditions,the drawing speed of 400?m/s have a better magnetic performance than the other two case of drawing speed,the remanence and coercivity are improved.Fe-25Cr-5Co alloys with drawing speed 1000?m/s have better performance the other two drawing speed.A magnetic field applying during annealing process is benefit to increase the remanence and coercivity of Fe-25Cr-12Co and Fe-25Cr-5Co alloys,and 1T magnetic field has a better effect to improve magnetic performance than 12T magnetic field.For a magnetically annealed FeCrCo alloy,a tempering process with magnetic field further improve the magnetic performance compared with tempering without magnetic field.Under all the experimental conditions in this research,a second tempering process further improve the magnetic performance. |
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