Investigation of porosity, texture, and deformation behavior using high energy X-rays during in-situ tensile loading in additively manufactured 316L stainless steel

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

卷:810

Article

Murphy-Leonard, Aeriel D.^1,5  Pagan, Darren C.^3,6  Callahan, Patrick G.²  Heinkel, Zach K.⁴  Jasien, Christopher E.⁴  Rowenhorst, David J.² 

[1] Natl Res Council Postdoctoral Associate, 4555 Overlook Ave SW, Washington, DC 20375 USA

[2] US Naval Res Lab, 4555 Overlook Ave SW, Washington, DC 20375 USA

[3] Wilson Lab, Cornell High Energy Synchrotron Source, 161 Synchrotron Dr, Ithaca, NY 14850 USA

[4] Naval Surface Warfare Ctr, Carderock Div, 9500 MacAuthor Blvd, West Bethesda, MD 20817 USA

[5] Ohio State Univ, Dept Mat Sci & Engn, 140 W 19th Ave, Columbus, OH 43210 USA

[6] Penn State Univ, Dept Mat Sci & Engn, 116 Deike Bldg, University Pk, PA 16802 USA

关键词: Additive manufacturing;    Damage evolution;    X-ray computed tomography;    Synchrotron diffraction;    Tensile loading;    316L Stainless steel;   

DOI  :  10.1016/j.msea.2021.141034

来源: Elsevier

【 摘 要 】

The evolution of damage, texture, and strain in additive manufactured (AM) 316L stainless steel produced via laser powder bed fusion was investigated during in-situ tensile loading using high energy X-rays. Synchrotron Xray computed tomography (XCT) measurements were performed to determine the initial porosity and monitor the evolution of porosity during tensile loading as well as detect the initiation and growth of voids from preexisting pore defects in the specimens. The as-built tensile specimens had a cross-sectional area of 1 mm2, which was chosen in order to understand damage behavior in thin-walled structures. Far-field X-ray diffraction measurements were performed to quantify crystallographic texture and the distribution of internal elastic strains during loading. The initial texture from the AM build process had a weak {220} texture aligned parallel to the build direction. As a result of tensile deformation, a strong {111} + {200} double fiber texture develops at high tensile strains and remains until fracture. XCT results confirmed that the inhomogeneous distribution of porosity near the surface played a significant role in damage evolution during tensile loading where voids and cracks initiated at pre-existing pores located within the contour zone. These pores were found to have asymmetric or irregular morphology. At high tensile strains, the massive accumulation of internal damage at these pores eventually connected to the surface reducing the ductility in these thin-walled AM samples and resulting in final failure.

【 授权许可】

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