Structure and Mechanical Properties of Iron Subjected to Surface Severe Plastic Deformation by Attrition: II. Mechanical Properties of Nano and Submicrocrystalline Iron

Depth sensing indentation is used to study the effect of grain refinement to submicro and nan ograins on the mechanical properties (hardness, plasticity, Young’s modulus) of armco iron subjected to severe plastic deformation by attrition in argon. In contrast to fcc metals, where the hardness increases and the plastic ity decreases as the grain size decreases to 20 nm, the hardness of bcc iron decreases from 5.8 to 3.7 GPa and plasticity δA increases from 0.82 to 0.87 as the grain size decreases from 50 to 20 nm