Highlights of the Study This study investigated the synthesis of nanostructured Fe–30 wt.% Mn alloy through high-energy mechanical alloying, focusing on the effects of milling time and ball-to-powder mass ratio on phase evolution, crystallite refinement, lattice strain, solid-solution formation, and particle morphology. Increasing both milling time and milling intensity promoted Fe–Mn solid-solution formation and nanostructural refinement, with the combination of 10 h milling and a ball-to-powder mass ratio of 30 producing a homogeneous nonmagnetic γ-Fe-based Fe–Mn solid solution with a crystallite size of approximately 6 nm. Key findings: 🟢 Mechanical alloying synthesis: Nanostructured Fe–30 wt.% Mn alloy was successfully synthesized from high-purity elemental Fe and Mn powders using planetary high-energy ball milling under an argon atmosphere. 🟢 Processing parameters: Two ball-to-powder mass ratios, 20 (S20) and 30 (S30), were investigated to determine the influence of milling intensity on Fe–Mn alloy formation and nanostructural refinement. 🟢 Milling-time effect: Increasing milling time from 5 to 10 h substantially reduced crystallite size and increased lattice strain for both S20 and S30 samples. 🟢 Crystallite refinement: For the S20 condition, crystallite size decreased from 60 nm after 5 h to 16 nm after 10 h of milling. 🟢 High-energy refinement: Increasing the ball-to-powder mass ratio to 30 produced substantially finer crystallites, with crystallite size decreasing from 14 nm after 5 h to only 6 nm after 10 h. 🟢 Lattice-strain increase: Lattice strain increased progressively with both milling time and milling intensity, reaching 1.93% for the S30 sample after 10 h compared with 0.19% for S20 after 5 h. 🟢 Phase transformation: The initial powder mixture consisted of α-Fe and α-Mn phases. At a ball-to-powder ratio of 30, 5 h milling produced a mixture of α-Fe and γ-Fe phases. 🟢 Single γ-phase formation: After 10 h of milling at a ball-to-powder mass ratio of 30, only the nonmagnetic γ-Fe phase was detected and the α-Mn phase disappeared completely, confirming extensive Fe–Mn solid-solution formation. 🟢 Milling-intensity effect: A higher ball-to-powder mass ratio increased milling energy, shortened the diffusion paths required for Fe–Mn solid-solution formation, and produced smaller crystallites with greater lattice strain. 🟢 Lattice-parameter evolution: Changes in XRD peak positions demonstrated modification of the lattice parameter during mechanical alloying, providing evidence of progressive Mn dissolution and Fe–Mn solid-solution development. 🟢 Particle morphology: The initial Fe–Mn powder mixture contained relatively large plate-like particles together with smaller particles and exhibited a broad particle-size distribution. 🟢 Morphological transformation: After 10 h of high-energy milling, the particle morphology changed substantially from plate-like particles toward a more equiaxed morphology. 🟢 Particle-size reduction: Prolonged mechanical milling reduced the average particle size while simultaneously producing relatively large and loose agglomerates as a consequence of deformation and cold welding. 🟢 Homogeneous elemental distribution: SEM/EDS elemental mapping of the 10 h S30 sample demonstrated that Fe and Mn were homogeneously distributed at the atomic scale. 🟢 Solid-solution confirmation: The combination of homogeneous Fe/Mn elemental mapping and XRD results confirmed formation of an Fe–Mn solid solution in the final mechanically alloyed powder. 🟢 Optimal processing condition: Among the investigated conditions, 10 h milling with a ball-to-powder mass ratio of 30 provided the most effective combination for obtaining a homogeneous nanostructured Fe–30Mn alloy with a crystallite size of approximately 6 nm. 🟢 Biomedical relevance: The synthesized nanostructured Fe–30Mn powder was proposed as a potential biodegradable metallic material for the production of temporary medical implants. Overall, the study demonstrates that milling time and ball-to-powder mass ratio are critical parameters governing the formation of nanostructured Fe–30Mn alloys by mechanical alloying. Increasing the ball-to-powder ratio from 20 to 30 and extending milling to 10 h promoted solid-solution formation, increased lattice strain, transformed the particles from plate-like to equiaxed morphology, and reduced the crystallite size to approximately 6 nm. The resulting homogeneous Fe–Mn nanostructured powder provides a potential starting material for biodegradable metallic implant applications. ARTICLE LINK https://doi.org/10.1016/j.mspro.2015.11.134 DOI 10.1016/j.mspro.2015.11.134 HOW TO CITE Safaie, N.; Khakbiz, M.; Sheibani, S.; Sotoudeh Bagha, P. Synthesizing of Nanostructured Fe-Mn Alloys by Mechanical Alloying Process. Procedia Materials Science 2015, 11, 381–385. DOI: 10.1016/j.mspro.2015.11.134. KEYWORDS Mechanical Alloying • Nanostructured Fe–Mn Alloy • X-ray Diffraction • High-Energy Ball Milling • Biodegradable Alloy