Refinement of the Crystal Structure of Low-Carbon Polycrystalline AISI 420 Martensitic Steel (C = 0.15%)

Although several works have proposed modeling the low-carbon steel lattice parameters considering their carbon content, no detailed information about the crystalline structure has been reported. Herein, the crystal structure of the polycrystalline martensitic steel with carbon content of 0.15% has been refined, giving details about the sites and occupancies for the iron and chromium atoms. The body-centered tetragonal crystal system with space group I 4/mmm was considered for the refinement. The obtained results show that the refined occupancies for Fe and Cr (around 0.83 and 0.17, respectively) are close to the values reported in the technical references for this kind of steel. The final structure yields a well-adjusted refinement, with R wp = 8.49%, gof = 1.70, and R Bragg = 3.17%.