Al元素添加对(Fe73Ga27)99.8Tb0.2 合金微观结构、磁性能及力学性能的影响

Effect of Al Addition on Microstructure, Magnetic Proper-ties, and Mechanical Properties of (Fe73Ga27)99.8Tb0.2 Alloy

摘要:

通过真空电弧炉制备(Fe₇₃Ga_27-xAl_x)_99.8Tb_0.2（x=0，1，2，3，4，5）合金，研究Al添加对合金的微观结构、磁性能和力学性能的影响。结果显示，合金的相结构仍为A2相和Tb₂Fe₁₇相，其金相组织由胞状晶和柱状树枝晶组织组成。合金的晶格常数降低、(100)取向性增强以及晶界处的Tb₂Fe₁₇相对磁致伸缩性能有显著影响。合金的断口形貌为沿晶脆性断裂和解理断裂，产生断裂的原因包括Tb和Al元素偏析。(Fe₇₃Ga₂₄Al₃)_99.8Tb_0.2合金的平行磁致伸缩应变（λ_∥）最高达到1.04×10^-4。值得注意的是，相比于(Fe₇₃Ga₂₇)_99.8Tb_0.2合金，(Fe₇₃Ga₂₆Al₁)_99.8Tb_0.2合金的λ_∥提高了18.3%，伸长率提高了53.4%，并且(Fe₇₃Ga₂₆Al₁)_99.8Tb_0.2合金兼具高饱和磁化强度（M_s）、低剩余磁化强度（M_r）和矫顽力（H_c）等特性，在实际生产中可以降低生产成本，但该合金的抗拉伸强度和维氏硬度有所下降。因此，研究Al元素添加对Fe-Ga合金的微观机理对开发Fe-Ga合金器件具有重要意义。

Abstract:

(Fe₇₃Ga_27-xAl_x)_99.8Tb_0.2 (x=0, 1, 2, 3, 4, 5) alloys were prepared by vacuum arc furnace to investigate the effect of Al addition on the microstructure, magnetic properties, and mechanical properties of alloys. Results show that the phase structure of the alloys is still A2 phase and Tb₂Fe₁₇ phase, and the metallographic structure is composed of cellular crystal and columnar dendrite. The decrease in lattice constant, the intensification of (100) orientation, and the generation of Tb₂Fe₁₇ phase at the grain boundary exert significant effect on the magnetostrictive properties. The fracture morphology of the alloys is intergranular brittle fracture and cleavage fracture, and the causes of fracture occurrence include the segregation of Tb and Al elements. The parallel magnetostrictive strain (λ_∥) of (Fe₇₃Ga₂₄Al₃)_99.8Tb_0.2 alloy peaks at 1.04×10^-4. It is worth noting that compared with those of (Fe₇₃Ga₂₇)_99.8Tb_0.2 alloy, the λ_∥ and elongation of (Fe₇₃Ga₂₆Al₁)_99.8Tb_0.2 alloy increase by 18.3% and 53.4%, respectively. Besides, (Fe₇₃Ga₂₆Al₁)_99.8Tb_0.2 alloy possesses the characteristics of high saturation magnetization (M_s), low remanent magnetization (M_r), and coercivity (H_c), which is beneficial to reduce the cost in actual production, but its tensile strength and Vickers hardness decrease to a certain extent. Therefore, the investigation on the micro-mechanism of Al addition on Fe-Ga alloys is of great significance for the development of Fe-Ga alloy devices.