工业纯铁退火过程中的位错密度和磁性能EI北大核心CSCD

针对热轧工业纯铁退火过程的微观组织和磁性能,采用X射线衍射和磁滞分析法分别研究位错密度、最大磁导率、矫顽力和剩磁的演变规律。结果表明:退火前后工业纯铁的近等轴晶组织没有明显变化,晶粒度约为3.70级;随着650℃退火时间延长至5 h,位错密度从初始热轧态1.80×10^(14)m^(-2)逐渐降低至1.16×10^(14)m^(-2),降幅约35%,同时衍射峰在退火初期发生一定程度左移,并在后期明显右移,表明微观存在压应力及后续释放过程。随退火时间延长,最大磁导率整体呈上升趋势,矫顽力和剩磁存在突变点,磁滞回线形状较窄、变化不大,分析认为主要与位错密度、内应力和含碳量相关。退火处理可以改善工业纯铁的磁性能,进一步考虑成分进行一体化调控将提升工业纯铁磁性能并拓展其电磁应用空间。

Dislocation density and magnetic properties of industrial pure iron during annealing

To investigate the microstructure and magnetic properties of hot-rolled industrial pure iron during annealing, X-ray diffraction and magnetic hysteresis analysis were performed. The evolution of dislocation density, and magnetic parameters, i.e. the maximum permeability, coercivity, and remanence, were analyzed respectively. Results show that the near equiaxed grain structure of industrial pure iron has no obvious change before and after annealing, and the grain size number is about 3.70. With the annealing time increasing to 5 h at 650 ℃, the dislocation density gradually decreases from the hot-rolled state of 1.80×10¹⁴ m^-2 to 1.16×10¹⁴ m^-2, with an amplitude of 35%. At the same time, the diffraction peaks are observed to shift to the left to a certain extent compared with the hot-rolled state, and then to the right. It indicates that the existence of residual compressive stress in micro scale and a subsequent releasing process. The shape of the magnetic hysteresis loops is narrow and changes little with the increase of annealing time. However, the maximum permeability shows a continuous increment, and some abrupt changes are observed in the coercivity and remanence.This might be attributed to the comprehensive influences of dislocation density, internal stress and carbon content. It is indicated that annealing treatment could improve the magnetic properties of industrial pure iron. With a further consideration of the effects of impurity elements, an integrated strategy of composition and microstructure control will improve the ferromagnetic performance of industrial pure iron and expand its electromagnetic applications.