Issue 60

L. Wang, Frattura ed Integrità Strutturale, 60 (2022) 380-391; DOI: 10.3221/IGF-ESIS.60.26

Microstructure and anisotropic tensile performance of 316L stainless steel manufactured by selective laser melting

Lin Wang Department of Civil Engineering, Hefei University, Anhui, China linw@smu.edu, http://orcid.org/0000-0002-6481-2409

A BSTRACT . The selective laser melting (SLM) technology is widely used to manufacture 316L stainless steel (SS) components for industrial applications. To understand the microstructure and the mechanical properties of additively manufactured 316L alloy, bulk materials were fabricated in longitudinal and transverse directions from which subset tensile specimens were then machine. Bulk materials were subjected to porosity detection with X-ray computed tomography and texture analysis with electron backscatter diffraction (EBSD). Microstructural investigations reveal that the SLM-built specimens had a porosity of 1.87%, and a preferential {110} orientation parallel to the build direction. The transverse specimens show significantly better properties in elastic modulus E (215.1±4.7GPa), yielding stress σ y (548.2±8.3MPa) and ultimate tensile strength UTS (705.6±2.9MPa) than the longitudinal ones ( E of 175.9±9.8GPa, σ y of 495.3±15.5 and UTS of 608.8±3.6MPa). The anisotropic mechanical performance was attributed to the preferential {110} texture caused by thermal conditions during manufacturing and the embedded voids due to insufficient melting. A three-parameter Weibull distribution was adopted to further describe the mechanical anisotropy of SS316L based on stochastic experimental measurements. Fractography indicated the existence of manufacturing defects that drive to premature failure of SS316L specimens—around half SS316L specimens failed of elongation less than 0.4. K EYWORDS . Selective laser melting; 316L stainless steel; Porosity; Mechanical anisotropy; Weibull distribution.

Citation: Wang, L., Microstructure and anisotropic tensile performance of 316L stainless steel manufactured by selective laser melting, Frattura ed Integrità Strutturale, 60 (2022) 380-391.

Received: 12.01.2022 Accepted: 14.02.2022 Online first: 05.03.2022 Published: 01.04.2022

Copyright: © 2022 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

I NTRODUCTION

elective laser melting (SLM) is an additive manufacturing (AM) technique whereby structures are built in a repeated layer-wise fashion via selectively or localized melting using high-intensity laser energy and solidification from metallic powder bed feedstock. Compared to conventional subtractive manufacturing methods, the key benefit of SLM is the ability to rapidly fabricate customized mechanical components of complex geometry, with the potential for improved S

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