Influence of defect characteristics on tensile deformation of an additively manufactured stainless steel: Evolutions of texture and intergranular strain

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:791

Article

Choo, Hahn¹  Koehler, Michael R.²  White, Logan P.¹  Ren, Yang³  Morin, Derek⁴  Garlea, Elena⁴ 

[1] Univ Tennessee, Mat Sci & Engn, Knoxville, TN 37996 USA

[2] Univ Tennessee, Joint Inst Adv Mat, JIAM Diffract Facil, Knoxville, TN 37996 USA

[3] Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA

[4] CNS Y 12 Natl Secur Complex, Oak Ridge, TN 37831 USA

关键词: Laser powder bed fusion;    Steel;    Texture;    Deformation;    Additive manufacturing;    Diffraction;   

DOI  :  10.1016/j.msea.2020.139637

来源: Elsevier

【 摘 要 】

The micromechanics of plastic deformation behavior of a selective laser melt processed austenitic stainless steel were studied by investigating the evolutions of texture and intergranular strain using in situ high-energy synchrotron x-ray diffraction (sXRD). The effects of defect characteristics on tensile behavior were studied using three different samples: a near full-density sample with elliptical closed voids and two samples with lack-of-fusion (LOF) defects tensile loaded either perpendicular or parallel to their major axes. The evolutions of pole figures and inverse pole figures show that the full-density specimen develops a strong (111)/(200) fiber texture along the loading direction. For both LOF specimens, the evolution of texture is qualitatively similar to the full-density counterpart, but the development of the fiber texture was much slower, indicating a limited plasticity at a given macroscopic strain. The intergranular strain evolution in the full-density specimen is similar to that of a wrought 316L stainless steel. Conversely, a significantly different intergranular strain development was observed in a LOF specimen, where tensile strain development was observed in both the axial and transverse directions. The influence of defect type, density, and orientation on the local stress states in the steel matrix and the evolutions of intergranular strains is discussed.

【 授权许可】

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