Advances in Surface Engineering: On-Demand Advances in Surface Engineering
Sponsored by: TMS Surface Engineering Committee
Program Organizers: Rajeswaran Radhakrishnan, Faraday Technology Inc; Brian Skinn, OpenTeams, Inc.; Timothy Hall, Faraday Technology Inc; Michael Roach, University of Mississippi Medical Center; Sandip Harimkar, Oklahoma State University; Tushar Borkar, Cleveland State University; Rajeev Gupta, North Carolina State University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 12
Location: MS&T On Demand
Session Chair: Holly Garich, Faraday Technology, Inc; Rajeswaran Radhakrishnan, Faraday Technology, Inc.
High Adhesive Joint Durability of Aluminum Alloys with Chemical Free Treatments: John Ho1; Alp Manavbasi1; 1Novelis
Surface pretreatments are often used to activate and functionalize the metal surfaces to provide enhanced adhesion and bond durability for adhesive joints or subsequent coatings. For aluminum sheet materials, such as 6xxx-series wrought alloys designed for automotive applications, wet chemical cleaning and pretreatment are widely used methods for improving coatings and adhesive joints with high corrosion resistance and durability. Current laboratory experimentation in this work explores an alternative surface treatment method without any wet cleaners and/or pretreatment chemicals with improvements in cleanliness and corrosion resistance. Simultaneous surface cleaning and activation for durable adhesive joints by using highly energetic laser ablation and texturing on the surface of the aluminum are demonstrated without any conventional wet surface treatment chemistries. In addition to the characterization and quantification of cleaned, activated and textured surfaces, improvement in adhesive joint durability in a corrosive environment will be presented.
Influences of Varied Electro-discharge Machining Operations on Surface Conditions of a Nickel-Base Superalloy: Tim Gabb1; T. Smith1; J. Telesman1; C. Kantzos1; R. Rogers1; D. Brinkman2; T. Ubienski2; 1NASA Glenn Research Center; 2HX5 Sierra, LLC
Nickel-base superalloys designed for use in gas turbine engines blades are difficult and expensive to properly machine without undue surface damage, due in part to their superior mechanical properties at high temperatures. Numerically controlled electro-discharge machining (EDM) has progressed to commonly be used as a machining process for initial sectioning, detailed roughing, and even finishing operations. The objective of this study was to examine the resulting surface conditions of superalloy 718 after sectioning using typical roughing, semi-finishing, and finishing conditions with a typical EDM machine. Sections were sliced with brass wire. Surface roughness, microstructure, and residual stress were compared for varied conditions. While roughness decreased when progressing from roughing to finishing EDM conditions, significant tensile residual stresses remained present. The varied EDM conditions also influenced the microstructure near the surface.
Ionic Polymer-Metal Composite (IPMC) Degradation Study and Solution Considerations for Biomimetic Thin-film Actuator Applications: Allison Arnold1; Kavin Sivaneri Varadharajan Idhaiam1; Lisa Hilgar1; William Brion1; Edward Sabolsky1; Ji Su2; 1West Virginia University; 2NASA Langley Research Center
The development of high-quality and cost-effective materials engineered for specific property enhancements has resulted in the development of adaptable multifunctional materials. Ionic-type electroactive polymers (I-EAPs) and ionic polymer-metal composites (IPMCs) have great promise as electromechanical sensors and actuators due to their relatively large responses to low applied voltages (≤ 3 V) and mechanical strains. Investigations into IPMC’s performance potentials as actuators have proven challenging due to the material’s high susceptibility to external influence (voltage, environmental conditions, external loads, etc.). Most significant is the material’s performance correlations with saturation level. This research seeks to not only to characterize and quantify the material’s hydration responsive behaviors, but also investigate potential solutions which would allow for increased service life of the actuator. Most notably is the consideration of surface engineered modifications to IPMC actuators, including encapsulation solutions for inert isolation of the material, and emphasis of the material’s biomimetic and bio-compatible features.
Mechanical Ball Milling of Gas Atomized Ti‒48Al‒2Cr‒2Nb Powder for Preventing Smoking in Electron Beam Additive Manufacturing Process: SeungKyun Yim1; Huakang Bian2; Keiji Yanagihara2; Kenta Aoyagi2; Akihiko Chiba2; 1Tohoku University; 2Institute for Materials Research, Tohoku University
In recent years, dense TiAl parts have been fabricated via electron beam additive manufacturing (EBAM) technology. However, one problem to apply EBAM for producing TiAl parts is sudden powder spreading, also known as “smoking”. One main reason is that the gas atomized TiAl powder is encapsulated by an electrically insulating oxide layer acting as a capacitor, which inhibits the charge redistribution across particle contacts. In the present study, the ball milling treatment is carried out to manipulate the powder surface of Ti‒48Al‒2Cr‒2Nb alloy to prevent smoking in the EBAM process. The electrical properties of ball milling powders are investigated by impedance spectroscopy with the corresponding electrical circuit fitting. The oxide layers of both raw and ball milling powders are characterized using X-ray photoelectron spectroscopy and transmission electron microscopy.
Surface Evolution and Corrosion Behavior of Cu-doped Carbide-reinforced Martensitic Steels in a Sulfuric Acid: Kenta Yamanaka1; Manami Mori2; Kazuo Yoshida1; Akihiko Chiba1; 1Tohoku University; 2National Institute of Technology, Sendai College
High-speed steels comprise martensitic matrices reinforced with fine carbide precipitates, exhibiting excellent wear resistance. However, the existence of high fraction of carbide precipitates causes an accelerated anodic dissolution of the martensitic matrix. Recently, we revealed that adding trace Cu significantly improves the corrosion resistance of such steel grades. In this study, to understand the underlying mechanism, we examined the surface evolution of the developed steels during immersion into a sulfuric acid. Using Kelvin probe force microscopy, we demonstrated that the difference in electrochemical potential between the carbide phase and the martensitic matrix, which acts as the driving force of the corrosion reaction, was reduced in the developed steel. Notably, heat-treatment temperature not only reduce the carbide fraction but also enhanced such a surface evolution, associated with surface Cu enrichment. Thus, the lower corrosion rate was obtained after quenching from higher temperatures.
Erosion Resistant and Passively Emitting Composite Coatings for Space Charge Mitigation Applications: Rajeswaran Radhakrishnan1; Danny Liu1; Timothy Hall1; Maria Inman1; Earl Jennings Taylor1; Stephen Snyder1; Matthew Robertson2; Trace Taylor2; JR Dennison2; 1Faraday Technology Inc; 2Utah State University
National Space Weather Strategy and Action plan calls for the need to enhance Protection of National Security, Homeland Security, and Commercial Assets and Operations against Effects of Space Weather. Ionizing radiation occurring as a result of space weather events can create negative surface charges, leading to ion sputtering, arcing, and/or parasitic current that damages spacecraft components, reducing their functionality and lifetimes. Therefore, developing a scalable manufacturing process to apply a lightweight passively emitting/erosion resistant coating that can mitigate charging and erosion effects from ionizing radiation is of interest. In this presentation, we will discuss the feasibility of a scalable manufacturing process for depositing a durable, highly emissive composite coating on spacecraft viable substrates. The composite coating shows a 140% increase in maximum total electron yield over Al, extending by 4x the range of electron yields between crossover energies >1, and maintained nominal emission properties in modeled ISS plasma erosion.