The segregation of phosphorus and the effect of phosphorus on the morphology were investigated by means of metallograph, EPMA and TEM in three kinds of Fe-P alloys (0.007wt%P, 0.06wt%P, 0.09wt%P) cold rolled70% and vaccum annealed (200 ℃～700 ℃). Mechanical test and electrochemical corrosion test were also carried out to anlayse the effect of P on mechanical properties and intergranular corrosion. The results show that phosphorus scgregates to dislocation and grain bowndary during annealing. P-riched, dense dislocation region and P-poored region and obvious subgains are formed during recovery, the unclei of recrystallization preferentially form at the permanent distortion region where dislocation is denad and phosphorus segregates strongly. Phosphorus increases the nucleation rate and decreases the growth rate after recrystallization, and makes the recrystallization grain small in Fe-P al. loys. Besides hardening of solid solution, phosphorus in solid solution pins against the motion of dislocation because of the segregation of P to dislo. cation, and phosphorus makes the recrystallization grain small, so increases the deformation resistance of Fe-P alloys, therefore increases strength. The phosphorussimilar to C.N segregates to dislocation and forms the Cottrell clouds, so that mades alloys appear yield phenomenon during recovery at high temperature and recrystallization. Phosphorus promotes the anodic dissolution of iron, and prevents the formation of a passive layer on iron in a nitrate solution. Especially, phosphours segregation to the dislocation and grain boundary mades it more difficulty to form a passive layer on iron during recovery and recrystallization. The grain boundary segregation of phosphorus accelerates intergranular corrosion of iron and decreases partial corrosion resistance of Fe-P alloys.
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