Microstructural Effects on the Environmental-Assisted Cracking of Advanced Manufactured Stainless Steels in Marine Environment (YIP-white paper track number: 21-000001332)
Abstract
Additive manufacturing (AM) refers to a group of advanced manufacturing technologies that create objects in a layer-wise manner and is especially appealing to industries that are targeted at low volume production of highly customized parts. It also provides the ab ility of on-demand manufacturing and repair (e.g. at sea, in space) as well as manufacturing of compositionally/functionally graded parts. Powder-based AM techniques such as direct energy deposition (DED) and selective laser powder bed fusion (LPBF) are mostly use d in the fabrication of dense metallic structures. Among the materials that can be produced by AM, 316L SS is particularly of intere st in marine applications due to its relatively superior ductility and excellent corrosion resistant property.The rapid solidificati on process and complex thermal cycles in AM lead to unique microstructural features and defects. The correlation between the complex microstructure of AM alloys and their cracking and fatigue properties in corrosive environment is becoming a topic of increasing in terest to realize the full potential of AM technique. However, the studies on environmentally-assisted cracking behaviors of AM 316L SS in marine environment are significantly lacking. The relationship between microstructural/chemical features and corrosion- relat ed behaviors remains elusive.The proposed research program aims to fill the gap in the current study by 1) investigating the effect of anisotropic microstructures (solidification texture and grain directionality) unique to the AM process on corrosion properties ov er a wide temperature range; and 2) understanding the corrosion and mechanical properties of hybrid conventional/printed SS structur es that contain single/multiple scans and varying number of printed layers and how their properties differ from the conventional or AM bulk counterparts. Primary focus will be placed on LPBF 316L SSs in sodium chloride solutions with concentration close to that of the seawater. To achieve these objectives, the proposed comprehensive technical efforts include electrochemical analysis of corrosi on characteristics, stress corrosion cracking, high cycle fatigue and crack propagation testing in corrosive environment, advanced m aterials characterization of microstructural features before and after cracking, as well as data-informed multiphysics modeling of t he electrochemical- mechanical processes, enabled by the multidisciplinary background of the PI.The success of the proposed program will reveal the microscopic features and underlying mechanisms that control the corrosion, cracking and failure of AM alloys in corr osive environment, and thus will guide the design and manufacturing of AM alloys and prolong their service life by controlling the m ost critical features/defects. The multiphysics computational framework established for understanding the microstructure-electrochem ical/mechanical properties linkages in AM alloys will expedite the process and greatly reduce the cost of corrosion-informed materia ls design and manufacturing, providing significant contribution to Office of Naval Research Corrosion Control Science & Technology P rogram. The impact on DoD capabilities will also be ensured by integrating the proposed research with the U.S. Naval Research Labora tory on-going efforts on establishing computational predictive model in the anti-corrosion properties of AM materials.Approved for P ublic Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 20, 2021
- Source ID
- N000142112800
Entities
People
- Yao Fu
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech