Synthesis of high-strength bimodally grained iron by mechanical alloying and spark plasma sintering

Nanocrystalline iron synthesized by mechanical alloying and spark plasma sintering exhibited high yield and ultimate compressive strengths of 2.59 and 3.08 GPa, respectively, with a total true strain of 0.05. Partial recrystallization led to a true strain of 0.4 with a lower strength of 2.25 GPa. A bimodal grain size distribution consisting of average fine grains of 2.5 μm and nanograins of 85 nm is attributed to the combined high strength and large plastic strain.