累积叠轧方法制备高性能FeCrCo/MnGa纳米晶复相永磁材料及其性能的基础研究

High performance Fe-base permanent magnetic material is the key technology to the implementation of new generation dynamic systems, and it is also benefit to save noble metal and rare earth. FeCrCo and MnGa powders were used in this project to form a composite by Accumulative Roll Bonding technique. We will then anneal the composites under high magnetic fields to promote the formation of the desirable intermetallic compounds in MnGa alloys and textured composite. The high magnetic field is used to improve the magnetic properties though altering microstructure by three mechanisms: (1) Refinement and preferred orientation growth of hard magnetic particles under spinodal decomposition, <001> texture in FeCrCo alloys is promoted; (2) morphology, size , Composition and magnetic property of compounds formed in MnGa layer, the alignment of compound phase in same direction; (3) Prevention of grain growth coarsening, Inhibition of undesired phase content during heat treatment. The project will aim to fabricate FeCrCo/MnGa permanent magnetic nanomaterial with high magnetic and mechanical performance, and to develop a new method of magnetic nanomaterial fabrication.

FeCrCo/MnGa纳米复合材料是一种节约贵金属、环保型、具有较高的理论磁能积和力学性能，可实现新一代动力系统的关键永磁材料。本项目拟采用累积叠轧与强磁场相结合的新手段，实现FeCrCo合金与MnGa合金颗粒的叠轧复合，以强磁场控制热处理环节中合金的相变过程。研究解决FeCrCo/MnGa复合材料磁交换耦合的关键问题: 1) FeCrCo合金调幅分解硬磁粒子的生长形态和取向的控制，使铁磁性粒子沿<001>易磁化方向规则排列；2) MnGa合金退火新生相的形态、尺度与成分的控制，使硬磁相沿相同方向取向排列。3) 热处理过程中FeCrCo与MnGa晶粒粗化以及有害相的抑制。获得纳米尺度的软磁相与硬磁相规则间隔排列的磁交换耦合结构，从而开发一种高性能、新型纳米晶复相永磁材料及其制备方法，为新一代动力系统的开发提供关键永磁材料。

本项目针对一种环保经济型的新型FeCrCo/MnGa纳米复合材料的制备方法与组织性能开展研究。基于纳米复合材料的磁交换耦合原理，分别制备了FeCrCo与MnGa两种分别具有高剩磁与高矫顽力的磁性合金，并实现FeCrCo/MnGa复合材料的制备，以强磁场控制热处理环节中合金的相变过程。研究解决了FeCrCo/MnGa复合材料磁交换耦合的关键问题: FeCrCo合金调幅分解硬磁粒子的生长形态和取向的控制；MnGa合金退火新生相的形态、尺度与成分的控制；热处理过程中FeCrCo与MnGa晶粒细化以及有害相的抑制。获得纳米尺度的软磁相与硬磁相的磁交换耦合结构。项目采用高分辨电镜分析了FeCrCo中的调幅分解机理，采用相场法数值模拟了FeCrCo的调幅分解机理，发展了相关的理论。并利用交流磁场、强磁场、机械合金化等多种手段完善了FeCrCo/MnGa复合材料的制备工艺。从而开发了一种高性能、新型纳米晶复相永磁材料及其制备方法。