Strain Induced Anisotropic Magnetic Behaviour and Exchange Coupling Effect in Fe-SmCo5 Permanent Magnets Generated by High Pressure Torsion
Strain Induced Anisotropic Magnetic Behaviour and Exchange Coupling Effect in Fe-SmCo5 Permanent Magnets Generated by High Pressure Torsion
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DOI：
10.3390/cryst10111026
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发表时间：
2020-11-01
期刊：
影响因子：
2.7
通讯作者：
Bachmaier, Andrea
中科院分区：
文献类型：
--
作者：
Weissitsch, Lukas;Stuckler, Martin;Bachmaier, Andrea
高压扭转（HPT）是一种强塑性变形（SPD）技术，是一种很有前途的大块交换弹簧磁性材料的加工方法。Fe和SmCo 5的粉末混合物通过HPT进行固结和变形，表现出几毫米的样品尺寸，对于大体积磁性应用是必不可少的。研究了化学成分分别为87，47，24和10 wt.%的Fe-SmCo_5化合物在室温和高温下HPT变形过程中的结构演变Fe进行了研究和微观结构分析。电子显微镜和同步辐射X射线衍射揭示了一个双相纳米结构的复合材料与晶粒细化后HPT变形变形的变形样品。SQUID磁强计测量显示在室温下的交换耦合纳米复合材料的磁滞曲线，而在低温下观察到的Fe和SmCo 5的去耦。此外，硬磁相和软磁相之间的交换相互作用可以解释磁滞曲线的偏移。重点是致力于磁性能和不断发展的纳米结构之间的相关性在HPT变形，这是进行1：1的组成比的Fe SmCo 5。SQUID磁强计测量显示增加的饱和磁化强度增加应变γ和最大的矫顽场强度在γ = 75的剪切应变。
High-pressure torsion (HPT), a technique of severe plastic deformation (SPD), is shown as a promising processing method for exchange-spring magnetic materials in bulk form. Powder mixtures of Fe and SmCo5 are consolidated and deformed by HPT exhibiting sample dimensions of several millimetres, being essential for bulky magnetic applications. The structural evolution during HPT deformation of Fe-SmCo5 compounds at room- and elevated- temperatures of chemical compositions consisting of 87, 47, 24 and 10 wt.% Fe is studied and microstructurally analysed. Electron microscopy and synchrotron X-ray diffraction reveal a dual-phase nanostructured composite for the as-deformed samples with grain refinement after HPT deformation. SQUID magnetometry measurements show hysteresis curves of an exchange coupled nanocomposite at room temperature, while for low temperatures a decoupling of Fe and SmCo5 is observed. Furthermore, exchange interactions between the hard- and soft-magnetic phase can explain a shift of the hysteresis curve. Strong emphasis is devoted to the correlation between the magnetic properties and the evolving nano-structure during HPT deformation, which is conducted for a 1:1 composition ratio of Fe to SmCo5. SQUID magnetometry measurements show an increasing saturation magnetisation for increasing strain gamma and a maximum of the coercive field strength at a shear strain of gamma = 75.