Fe-30Mn-6Si belongs to a multi-functional material and is one of the most attractive alloys for use in engineering applications, such as pipe joints, repairing bone defects in load-bearing areas, etc. The present work focuses on the effect of face-centered cubic (FCC) grain size on the FCC → hexagonal close-packed (HCP) martensitic transformation and mechanical properties of the Fe-30Mn-6Si biodegradable alloy (BA). The specimens which were fully recrystallized with different FCC grain sizes ranging from 8.2 to 15.0 μm were obtained by different annealing treatments following rolling. According to the results, Hall-Petch relationship of the Fe-30Mn-6Si BA was fitted as: σ_y = 58.9 MPa + 1080.4 MPa•μm^1/2 d_γ^–1/2. The ultra-high K value (1080.4 MPa•μm^1/2) indicates that the Fe-30Mn-6Si BA may exhibit ultra-high strength in ultra-fine grain structure. Remarkably, the Fe-30Mn-6Si BA annealed at 900 °C for 5 min overcame the strength-ductility trade-off which resulted in the higher yield strength, ultimate tensile strength and fracture elongation than the alloy annealed at 1000 °C for 5 min despite with a smaller grain size. In addition, compared to Mg- and Zn-based BAs, the Fe-30Mn-6Si BA exhibits superior mechanical properties.

Fe-30Mn-6Si 属于多功能材料，是工程应用中最具吸引力的合金之一，例如管道接头、修复承重区域的骨缺损等。目前的工作重点是FCC 上的面心立方 (FCC) 晶粒尺寸 → Fe-30Mn-6Si 可生物降解合金 (BA) 的六方密排 (HCP) 马氏体转变和力学性能。通过轧制后的不同退火处理得到充分再结晶的试样，FCC 晶粒尺寸范围为 8.2 ～ 15.0 μm。根据结果​​，Fe-30Mn-6Si BA的Hall-Petch关系拟合为： σ _y  = 58.9 MPa + 1080.4 MPa•μm ^1/2 d _γ ^–1/2. 超高的K值（1080.4 MPa•μm ^1/2）表明Fe-30Mn-6Si BA在超细晶粒结构中可能表现出超高强度。值得注意的是，在 900°C 退火 5 分钟的 Fe-30Mn-6Si BA 克服了强度-延展性权衡，导致比在 1000°C 退火 5 分钟的合金具有更高的屈服强度、极限抗拉强度和断裂伸长率尽管粒度较小。此外，与 Mg 和 Zn 基 BA 相比，Fe-30Mn-6Si BA 表现出优异的机械性能。