Dynamic recrystallization under hot deformation of additively manufactured 316 L stainless steel

Abstract

The high-temperature deformation behavior of additively manufactured 316 L stainless steels prepared via the laser powder bed fusion (LPBF) technology was investigated using Gleeble compression testing in a wide temperature range of 473–1273 K under a constant strain rate of 0.001 s−1, perpendicular to the building direction (BD). The softening flow property upon continuous concurrent isothermal heating deformation displayed an excellent thermal stability performance up to the temperature of 873 K, preserving the material strength higher than 600 MPa compared to the room-temperature property of the as-built material. By the gradual increase of testing temperature, the compressive strength of the material was continuously decreased to even <50 MPa at a temperature of 1273 K. After hot compression; all tested specimens were characterized across different regions in terms of deformation substructure evolution and crystallographic texture using electron backscattering diffraction (EBSD) and constitutive analyses. Accordingly, the estimated activation energies based on established constitutive modeling proposed the operation of dynamic recovery (DRV) and discontinuous dynamic recrystallization (DDRX) mechanisms for the hot deformation of additively manufactured 316 L stainless steel below (∼[Formula presented]) and higher (∼[Formula presented]) than the critical temperature of 873 K, respectively. The competition between strain accumulation and thermal heating induced two different Brass deformation and Goss recrystallization textures below and above this critical temperature by altering the operative dominant dynamic restoration mechanism, with various texture severity depending on the testing temperature.

Publication Title

Materials Characterization

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