Mn–Bi alloys modified with Mg and other elements were recently developed into promising rare-earth-free permanent magnets through successive melt spinning, warm compaction, and short magnetic field annealing. This letter reports on the crystal structures, texture, and magnetic properties observed in Mn₅₀Bi_49-$x$Mg_$x$Sb_0.5In_0.5 alloys ($x$ = 0, 1.5, 3.0, 4.5) throughout these processing steps. The Mg substitution favors MnBi-based intermetallic phases over the Bi- and Mn-based solid solutions and the stable α intermetallic phase over the metastable β′ intermetallic phase. Magnesium increases the $c/a$ ratio of the α phase lattice parameters for all studied $x$ values, and it increases the degree of the field-annealing-induced texture for $x$ ≤ 3. The effect of Mg on coercivity is explained as a combination of a positive one via the α phase magnetocrystalline anisotropy and a negative one via the development of texture. The effect of the substitution on the maximum energy product additionally involves the decreasing density of the alloys; the optimum $x$ is found to be ≈3. Also reported are the thermal properties of selected alloys. The mechanism of field annealing effect on the coercivity is briefly discussed.

中文翻译：

---

熔纺Mn-Bi-Mg-Sb-In合金中Mg含量对场退火磁铁组织和性能的影响

用镁和其他元素改性的锰铋合金最近通过连续熔体纺丝、温压和短磁场退火被开发成有前途的无稀土永磁体。这封信报告了在 Mn ₅₀ Bi _{49- 中}观察到的晶体结构、织构和磁性_$x$镁_$x$Sb _0.5 In _0.5合金 ($x$= 0, 1.5, 3.0, 4.5) 在这些处理步骤中。Mg 取代有利于 MnBi 基金属间相而不是 Bi 和 Mn 基固溶体和稳定的α 亚稳态上的金属间相 β'金属间相。镁增加$c/a$ 的比例 α 所有研究的相晶格参数 $x$ 值，它增加了场退火诱导的织构程度 $x$ ≤ 3. Mg 对矫顽力的影响被解释为正的组合，通过 α相磁晶各向异性和通过织构发展的负磁晶各向异性。置换对最大能积的影响还涉及合金密度的降低；最佳的$x$被发现是≈3。还报告了所选合金的热性能。简要讨论了场退火对矫顽力的影响机制。