Nanocrystalline steel obtained by mechanical alloying of iron and graphite subsequently compacted by high-pressure torsion

Steel powders obtained by mechanical alloying of iron and graphite were compacted by high-pressure torsion. During high-pressure torsion, mean grain sizes rise from about 10 nm after mechanical alloying to about 20 nm. Vickers hardness reaches values of more than 10 GPa. Differential scanning calorimetry revealed superabundant vacancies present in concentrations up to 10−3. The results are discussed in terms of strain, strain rate, energy input and deformation mechanisms.

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