Selective laser melting of iron: Multiscale characterization of mechanical properties.

The complex study of the mechanical properties of pure iron produced by selective laser melting (SLM) revealed enhanced values of the yield stress and ultimate tensile strength as compared to the material produced in a classic way. These values result from high dislocation density, presence of interstitial carbon and small precipitates. In-situ tensile experiments revealed that the basic mechanism of plastic deformation in this material, the structure of which was described in detail previously Mater. Charact. 154 (2019) 222], is the emission of dislocations from dislocation walls in the material. From the yield drop at the stress-strain dependence, the effective binding energy of carbon to dislocations is estimated. SLM iron also exhibits anisotropy of nanohardness showing maxima for orientations in the middle of the orientation triangle but also at {100} and {110} corners. This anisotropy suggests that the deformation is affected by the splitting of ½⟨111⟩ dislocations on {110} planes into partials on {112} planes. Image 1 • Deformation of SLM iron consists of emission of dislocations from dislocation walls, solute atmosphere and small particles. • The effective binding energy of carbon to dislocations was determined. • Anisotropy of nanohardness supports the complex behavior of dislocations in bcc iron. [ABSTRACT FROM AUTHOR]