High-entropy alloys, as a novel type of absorber, exhibit exceptional electromagnetic modulation capabilities and significant potential for electromagnetic wave absorption. In this work, the FeCoNiCrMn high-entropy alloy absorbent prepared through a mechanical alloying process demonstrates a dual-phase solid solution structure comprising face-centered cubic (FCC) and body-centered cubic (BCC) phases. By varying the manganese (Mn) content in the system, it is possible to enhance the degree of crystallinity, maintain the integrity of the crystal structure, and effectively control the relative proportion of the BCC phase within the overall phase composition. This adjustment improves the brittleness of the sheet-like particles, reduces particle size, and significantly lowers the permittivity. When the molar ratio of Mn is 0.6, the sample exhibits improved impedance matching due to the optimal permittivity and permeability. Notably, the impedance matching and attenuation constant can also be balanced. At 6.42 GHz, the FeCoNiCr0.4Mn0.6 alloy powder achieves the maximum reflection loss of −48.49 dB at a matching layer thickness of 3 mm. When the matching thickness is reduced to 2 mm, it can effectively cover a frequency range of 8.7–14.1 GHz (effective absorption bandwidth of 5.4 GHz), along with a wide absorption bandwidth and high absorption efficiency.

中文翻译：

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通过调整 FeCoNiCr0.4Mnx 高熵合金中脆性 BCC 相的比例来提高电磁波吸收性能


高熵合金作为一种新型吸收剂，表现出卓越的电磁调制能力和巨大的电磁波吸收潜力。在本工作中，通过机械合金化工艺制备的 FeCoNiCrMn 高熵合金吸收剂展示了由面心立方 （FCC） 和体心立方 （BCC） 相组成的双相固溶体结构。通过改变系统中的锰 （Mn） 含量，可以提高结晶度，保持晶体结构的完整性，并有效控制 BCC 相在整体相组成中的相对比例。这种调整提高了片状颗粒的脆性，减小了颗粒尺寸，并显著降低了介电常数。当 Mn 的摩尔比为 0.6 时，由于最佳介电常数和磁导率，样品表现出更好的阻抗匹配。值得注意的是，阻抗匹配和衰减常数也可以平衡。在 6.42 GHz 时，FeCoNiCr0.4Mn0.6 合金粉末在 3 mm 的匹配层厚度下实现了 −48.49 dB 的最大反射损耗。当匹配厚度减小到 2 mm 时，它可以有效覆盖 8.7–14.1 GHz 的频率范围（有效吸收带宽为 5.4 GHz），以及宽吸收带宽和高吸收效率。