钴基磁敏非晶合金非晶形成能力和塑性变形能力研究

Co-based amorphous magnetic-sensitive alloys exhibit near zero magnetostriction, superhigh permeability, high resistivity, and very low coercivity, which are potential for applications in electronics and communications industry. How to improve the glass-forming ability and plasticity of Co-based amorphous alloys while maintaining the excellent magnetic-sensitive properties is still unsolved. This project mainly focuses on improving the comprehensive properties of the Mo and rare-earth elements doped Co-based magnetic-sensitive amorphous alloys by utilizing synchrotron radiation technology of the microstructure observation. The goal of this project is to develop Co-based amorphous magnetic-sensitive alloys with excellent soft magnetic properties, large glass forming ability and high plasticity. A study about the Mo and rare-earth elements doping and its effects on the change of the local atomic structure in the alloys will be performed. The effect of the Mo and rare-earth elements doping on the glass-forming ability and plastic deformation ability will be interpreted from the perspective of microstructure analysis utilizing synchrotron technology.

钴基磁敏非晶合金兼具近零磁致伸缩、超高磁导率、高电阻率、极低矫顽力等特性，是在电子、通讯等行业应用前景广阔的一种新型材料，但如何在保持磁敏特性的同时，提高其非晶形成能力和塑性变形能力目前尚未解决。本项目以Mo元素和稀土元素掺杂调控钴基磁敏非晶合金的综合性能为主线，以微观结构同步辐射分析为基础，以期探索发现兼具优异软磁性能、大非晶形成能力和高塑性的钴基磁敏非晶合金。同时研究Mo元素和稀土元素掺杂前后合金局域原子结构，利用同步辐射微观结构分析解释Mo元素和稀土元素掺杂对合金非晶形成能力以及塑性变形能力的影响。

钴基非晶合金由于具有优异的软磁性能，大的非晶形成能力及超高强度而受到广泛关注，然而其室温变形能力较差，限制了其应用。本项目在课题组前期探索的具有大非晶形成能力及优异软磁性能的CoFeBSiNb非晶合金体系中，通过适量添加与Fe、Co具有正混合焓的Cu元素，以及具有大泊松比的Ni元素，提高了该钴基非晶合金系的室温塑性变形能力。利用X射线衍射（XRD）、同步辐射XRD、差示扫描量热仪（DSC）、电子万能试验机、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、球差校正电镜、振动样品磁强计（VSM）及交直流磁滞回线测量仪等设备分析了非晶合金的原子结构、热学性能、力学性能、断裂形貌及磁学性能等。研究表明，Cu、Ni的添加促使非晶基体中生成第二相纳米颗粒，与受力时产生的剪切带相交，导致剪切带的分枝，产生二级剪切带，这些剪切带彼此相交，阻碍样品的进一步变形直到断裂，导致了样品宏观塑性的提升。此外， Cu元素的适量添加可以提高合金的原子堆积密度，从而提高合金的强度。本项目成功制备了兼具大非晶形成能力、优异力学及软磁性能的[(Co0.7Fe0.3)0.68B0.219Si0.051Nb0.05]99.5Cu0.5非晶合金。其临界直径达4.5 mm，强度为4400 MPa，室温压缩塑性为2.5 %，饱和磁感应强度达0.73 T，矫顽力为1.32 A/m，进一步促进了钴基非晶合金的大规模工业应用。