Fe-B-P(C, Si)非晶合金的成分设计及软磁性能研究

Fe-based metallic glasses have attracted considerable research interests due to their successful commercial applications as transformer core laminations with their excellent soft magnetic properties. But the lower saturation magnetization of Fe-based metallic glasses than silicon steel restrict the application. In Fe-based metallic glass, high Fe content can improve the saturation magnetization, and the metalloid alloying is important to improve glass formation. However, it remains a mystery on the quantitative correlation between metalloid alloying and the formation of Fe-based metallic glasses. The variation of atomic structures and electronic structure underpins the physical origin of the effect of alloying elements on the glass forming ability and properties of Fe-based metallic glasses. This project will research the influence the electron concentration and atomic configuration on glass formation of Fe-B-P alloys through wide composition range. And the relationship between electronic concentration and glass forming ability will be discussed through experimental methods, combined with the first-principles molecular dynamics simulations to analysis the intrinsic correlation between preferred polyhedra type and glass forming ability. Then, the correlation between atomic structure and electronic concentration of Fe-based mtallic glasses will be discussed. According to the above results, novel Fe-B-P(C,Si) metallic glass with high Fe content and high glass forming ability will be developed through proper admixture of metalloid elements C or Si in Fe-B-P metallic glass with more than 80% Fe.Finally, These findings will provide new guideline on the accurate control of the metalloid concentration for developing Fe-based metallic glasses with good soft magnetic properties and high glass forming ability.

Fe基非晶合金具有较优异的综合软磁性能，将其制成小型配电变压器，满足节能减排的重大需求。但其局限是饱和磁感应强度（Bs）较低，造成产品体积较大，成本增加。增加Fe含量是提高Bs的有效手段，同时类金属的掺杂对改善非晶形成能力尤为重要。目前类金属掺杂仍是经验式，缺乏科学的理论指导。本项目拟以形成非晶成分范围较宽的Fe-B-P合金为研究对象，通过对富P区和富B区非晶形成能力和软磁性能的实验研究，揭示高非晶形成能力的电子浓度特征；通过第一性原理分子动力学方法模拟非晶合金中的团簇结构，探索Fe基非晶中出现几率最高的团簇类型与非晶形成能力的关系，揭示不同类金属元素在价电子数和原子半径方面的差异对非晶形成的影响；进而指导在高Fe含量（80%以上）的Fe-B-P非晶合金基础上掺杂C或Si，获得高Bs、低矫顽力的Fe-B-P(C, Si)非晶合金，最终为Fe基非晶合金中类金属的科学成分设计提供理论依据。

利用电子浓度规律设计Fe基非晶合金，获得了类金属替代对非晶形成能力的影响，揭示电子浓度与非晶形成能力的关联。通过对大量Fe基非晶合金原子结构的第一性原理分子动力学模拟结果的分析，结合铁-类金属非晶合金形成能力的实验结果，阐明了添加元素对α-Fe析出的影响，提出了Fe基非晶合金形成的临界电子浓度，对高Fe含量Fe基非晶合金的成分设计提供理论支持。利用临界电子浓度设计Fe含量高于80%的FePBSn、FeSiBSn、FeBC、FeBPSiMn等一系列非晶合金，研究了类金属替代对Fe基非晶软磁性能的影响。并进一步根据刚性能带模型和电子转移模型对Fe基非晶合金的饱和磁感应强度随成分的变化进行了讨论，得到一个饱和磁感应强度的成分计算模型，与实验测试获得的饱和磁感应强度具有良好的线性关系，为高饱和磁感应强度Fe基非晶合金的成分设计提供依据。