Environmental Degradation of Additively Manufactured Alloys: Aqueous and Atmospheric Corrosion II
Sponsored by: TMS Structural Materials Division, TMS: Corrosion and Environmental Effects Committee
Program Organizers: Kinga Unocic, Oak Ridge National Laboratory; Jenifer Locke, Ohio State University; Sebastien Dryepondt, Oak Ridge National Laboratory; Brendy Rincon Troconis, University of Texas at San Antonio; Andrew Hoffman, Catalyst Science Solutions; Xiaoyuan Lou, Purdue University
Wednesday 2:00 PM
March 22, 2023
Room: Sapphire 400A
Location: Hilton
Session Chair: Xiaoyuan Lou, Purdue University; Jennifer Locke, OSU
2:00 PM Invited
Small-Scale Mechanical and Corrosion Properties of Additively Manufactured Stainless Steel: Xiaolei Guo1; Yachun Wang2; Eric Schindelholz1; Gerald Frankel1; 1The Ohio State University; 2Idaho National Laboratory
A unique feature of stainless steel (SS) prepared by laser powder bed fusion (LPBF) is the presence of a large amount of oxide inclusions in the as-printed alloy substrate. Thermodynamic calculations suggest that these oxides are metastable, so their size and distribution can continuously evolve over time. Therefore, the nucleation, growth, and aggregation of the oxides and their influences on the mechanical and corrosion properties of the alloys must be understood. This study aims at exploring the role of oxide inclusions on the mechanical properties of AM-SS 316L by leveraging the small-scale, in situ tensile testing capability developed in Idaho National Laboratory. This approach enables accurate examination of the effect of oxide inclusions on the mechanical properties of LPBF-produced SS, which would not have been possible otherwise due to the interference of the overwhelming effect of porosity. The as-printed alloys were also subjected to heat treatment and pitting corrosion studies.
2:30 PM Invited
Comparing the Corrosion Response of Wrought and Cold Sprayed Aluminum Alloys: Luke Brewer1; Munsu Kim1; Ozymandias Agar1; Gregory Kubacki1; 1University of Alabama
This talk highlights the differences in corrosion behavior between cold sprayed and wrought high strength aluminum alloys: AA2024 and AA7075. Given its low thermal input, cold spray is showing great promise as a solid-state repair process for aircraft structures. The polarization response of high quality, cold sprayed aluminum is measurably, but not significantly, different from wrought materials. Distinct differences in the polarization response as a function of electrolyte chemistry are noted, with cold spray cathodic kinetics being slower than wrought in artificial seawater, but faster in sodium chloride electrolytes. The localized corrosion response is notably different from wrought materials with fewer, deeper pits formed in the cold sprayed material. Localized corrosion in cold sprayed materials initiates at prior particle boundaries as opposed to constituent particles in wrought alloys. Preferential corrosion along intermetallic networks influences the degradation of cold sprayed material, but at a different length scale than in wrought material.
3:00 PM
Corrosion Behavior of Additively Manufactured Al-Cr-Mn-Co-Zr Alloys: Sarshad Rommel1; Mingxuan Li1; Thomas Watson2; Callie Benson3; Rainer Hebert1; Mark Aindow1; 1University of Connecticut; 2Pratt & Whitney; 3Collins Aerospace
Recently, we have developed a series of Al-Cr-Mn-Co-Zr alloys that exhibit nano-composite microstructures in gas-atomized powders. The microstructures comprise an FCC Al matrix with quasicrystalline I-phase dispersoids. Upon consolidation, the I-phase is retained in the bulk material, which exhibits an impressive combination of mechanical properties and exceptional resistance to pitting in salt-fog exposures. These alloys are being explored for use in a variety of additive manufacturing techniques, including coatings and powder-bed AM for solid builds. A key concern is the possible influence of the additive manufacturing processes on the microstructures of the alloys and on their corrosion response. Here, we present preliminary observations on the corrosion behavior of additively manufactured samples upon exposure to Cl- rich environments through a combination of electron microscopy, focused ion-beam milling and potentiostatic polarization techniques. Comparisons with corrosive attack on these alloys in their bulk consolidated and upset-forged conditions will also be discussed.
3:20 PM Break
3:40 PM
High-pressure Cold Spray (HPCS) Coatings for Repair and Retrofit of Existing Large-scale Structures: Rose Gerani1; Baillie Haddad1; Aaron Nardi1; 1VRC Metal Systems
HPCS processing is a solid-state, additive manufacturing method of developing coatings with fine microstructures, high tensile strength and adhesion, superior wear performance, and tailorable anodic or cathodic corrosion protection. In structural applications, steel is often exposed to aggressive atmospheric conditions, which frequently occurs in highly polluted areas or near saltwater, causing higher corrosion rates than experienced in rural environments. Damage to critical structural members over time is unavoidable, due to any number of anticipated or unanticipated loading and environmental conditions. Conventional modes of repair, such as welding, often introduce additional problems, such as cracking caused by high tensile residual stresses at inherent discontinuities in the weld, corrosion sensitized areas adjacent to the weld repair, and weakening of the surrounding material from the heat input. In this ongoing work, HPCS coating is being optimized for corrosion and wear protection of structural steel, specifically targeting 1084 and R236 railway steel, using nitrogen.
4:00 PM Invited
Corrosion Behavior of Additively Manufactured Al-Ce-X and Al-10SiMg Alloys in 3.5 wt.% NaCl Solution: Jiheon Jun1; Alex Plotkowski1; Amit Shyam1; Sumit Bahl1; Ryan Dehoff1; Yi-Feng Su1; J. Allen Haynes1; 1Oak Ridge National Laboratory
Additively manufactured (AM) Al-CeNiMn, Al-CeNiMnZr and Al-10SiMg alloys have been evaluated for hybrid powertrain components in the next-generation automotive systems. The corrosion behaviors of these newly developed and commercial AM Al alloys were assessed in aggressive aqueous environments. Electrochemical impedance spectroscopy (EIS) and polarization techniques were employed to evaluate and compare the corrosion of the AM alloys to commercial 319 cast Al alloys in 3.5 wt.% NaCl solution. Long-term immersion tests in 3.5 wt.% NaCl solution were also performed, and the post-immersion samples were characterized using microscopic and X-ray spectroscopic techniques to investigate the microstructural features associated with corrosion attack. Based on our results, the relative corrosion resistance can be summarized as; 319 Al alloy (least resistant) < AM Al-CeNiMn < AM Al-CeNiMnZr ≈ AM Al-10SiMg.
4:30 PM
Corrosion and Wear-resistant Coatings for Nuclear and Automotive Applications by Using High-pressure Cold Spray Technology: Markus Brotsack1; 1Impact Innovations GmbH
In recent years, cold spray (CS) technology has been contemplated in many industries, e.g., aerospace, automotive, defense, electrical, nuclear, etc. CS process is well known for high powder feedstock deposition efficiency and low-temperature processes leading to oxygen-free deposits. The CS process offers substantial applications, for example, in-situ structural or dimensional restoration and surface coatings to enhance corrosion, fatigue, and wear resistance. Some potential applications of CS technology include mitigation and repair of stress corrosion cracking, intergranular attack, flow accelerated corrosion, and other types of corrosion by applying a protective coating to isolate the component's structural material from the corrosive environments. The present work demonstrates some relevant applications for the nuclear and automotive industry and discusses corrosion and wear-resistant materials. Automotive industry also requires high volume low cycle time manufacturing.