Effect of high magnetic field on recovery of martensitic structure in a Fe-C-W alloy steel
High magnetic field,as an important factor affecting metal phase transformation,can significantly increase the starting temperature of austenite to martensite transformation and affect the final microstructure of martensite.However,there is little research on the effect of high magnetic fields on martensitic recovery.The effect of high magnetic field on the recovery of martensitic structure in Fe-C-W alloy steel after tempering at different temperatures for 1 h was studied.The results show that the application of a high magnetic field significantly increases the number density of carbides in the matrix.The reason for this is that the high magnetic field increases the magnetization intensity of carbides,reduces their magnetic free energy,and increases their nucleation driving force.The inhibitory effect of high magnetic field on martensitic recovery is not significant during low-temperature tempering at 200℃.When the tempering temperature increases to 500 ℃,the application of a 12 T high magnetic field significantly enhances the hindering effect of carbides on dislocation movement,greatly suppressing the recovery of dislocations,and increasing the residual dislocation density in the matrix by about 27.5％.High density dislocations significantly increase the content of small angle grain boundaries,reducing the average width of martensite lath by about 137 nm,indicating that the application of high magnetic field significantly inhibits the recovery of martensite.
high magnetic fieldmartensite recoverycarbidedislocationlow angle boundary
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