Process-Structure-Property Relationships for 316L Stainless Steel Fabricated by Additive Manufacturing and Its Implication for Component Engineering

Journal Article · Thu Dec 08 00:00:00 EST 2016 · Journal of Thermal Spray Technology

DOI:https://doi.org/10.1007/s11666-016-0480-y· OSTI ID:1357021

Yang, Nancy ^[1]; Yee, J. ^[1]; Zheng, B. ^[2]; Gaiser, K. ^[1]; Reynolds, T. ^[1]; Clemon, L. ^[1]; Lu, W. Y. ^[1]; Schoenung, J. M. ^[2]; Lavernia, E. J. ^[2]

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1. Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2. Univ. of California, Irvine, CA (United States)

We investigate the process-structure-property relationships for 316L stainless steel prototyping utilizing 3-D laser engineered net shaping (LENS), a commercial direct energy deposition additive manufacturing process. Our study concluded that the resultant physical metallurgy of 3-D LENS 316L prototypes is dictated by the interactive metallurgical reactions, during instantaneous powder feeding/melting, molten metal flow and liquid metal solidification. This study also showed 3-D LENS manufacturing is capable of building high strength and ductile 316L prototypes due to its fine cellular spacing from fast solidification cooling, and the well-fused epitaxial interfaces at metal flow trails and interpass boundaries. However, without further LENS process control and optimization, the deposits are vulnerable to localized hardness variation attributed to heterogeneous microstructure, i.e., the interpass heat-affected zone (HAZ) from repetitive thermal heating during successive layer depositions. Most significantly, the current deposits exhibit anisotropic tensile behavior, i.e., lower strain and/or premature interpass delamination parallel to build direction (axial). This anisotropic behavior is attributed to the presence of interpass HAZ, which coexists with flying feedstock inclusions and porosity from incomplete molten metal fusion. Our current observations and findings contribute to the scientific basis for future process control and optimization necessary for material property control and defect mitigation.

• Research Organization: Sandia National Lab. (SNL-CA), Livermore, CA (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC04-94AL85000
• OSTI ID: 1357021
• Report Number(s): SAND-2017-4008; PII: 480
• Journal Information: Journal of Thermal Spray Technology, Vol. 26, Issue 4; ISSN 1059-9630
• Publisher: Springer
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
additive manufacturing
dendritic
LENS
porosity
stainless steel