Advances in Surface Engineering: Session I
Sponsored by: TMS Surface Engineering Committee
Program Organizers: Brian Skinn, OpenTeams, Inc.; Timothy Hall, Faraday Technology Inc; Michael Roach, University of Mississippi Medical Center; Tushar Borkar, Cleveland State University; Sandip Harimkar, Oklahoma State University; Rajeev Gupta, North Carolina State University
Wednesday 2:00 PM
November 4, 2020
Room: Virtual Meeting Room 22
Location: MS&T Virtual
Session Chair: Jing Xu, Faraday Technology, Inc.
2:00 PM
Effect of Surface Finish on the Corrosion Properties of Additively Manufactured Stainless Steel: Jamie Stull1; Courtney Clark1; Timothy Gorey1; Don Johnson1; Randy Edwards1; Enkeleda Dervishi1; Daniel hooks1; 1Los Alamos National Laboratory
Metal additive manufacturing (MAM) using powder-bed fabrication is a rapidly-developing technology. While the impact of this new production path could be significant, MAM products must still meet many traditional requirements, including surface specifications such as finish (roughness), coatings, and corrosion resistance. However, initial studies indicate that these requirements may not directly transfer to MAM materials, with complications due to different microstructures, hidden surfaces, difficult geometries, and rougher finishes expected. In this study, we focused on developing electropolishing techniques to improve the surface finish; characterizing the surface pre- and post-processing. Surface characterization was performed using profilometry, microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). We also explored how both surface and heat treatments affect the corrosion performance of the material using conventional electrochemistry and electrochemical AFM.
2:20 PM
Performance Analysis of Biomimetic Ionic Polymer-metal Composite (IPMC) Thin-Film Actuators: Allison Arnold1; Kavin Sivaneri Varadharajan Idhaiam1; Lisa Hilgar1; Edward Sabolsky1; Ji Su2; 1West Virginia University; 2NASA Langley Research Center
Electroactive polymers (EAPs) continue to gain attention for their potential to offer unique and versatile solutions in the soft robotic and flexible electronic industries. Ionic Polymer-Metal Composites (IPMCs), an ionic-type EAP, have great promise as electromechanical sensors and actuators due to their relatively large responses to low applied voltages (1-3 V) and mechanical strains. Investigations into IPMC’s performance potentials as actuators have proven challenging as the material is limited by the integrated solvent properties, predominantly water. As a result, the material’s performance largely correlates with hydration level throughout usage. This research seeks to not only to characterize and quantify these material behaviors, but also investigate potential solutions to allow for increased service life of the actuator, in addition to examining its adaptability towards biomimetic and bio-compatible applications. To accomplish this, the technology’s potential will be further expanded through incorporation of engineered micro-formed/actuated architectures, detailed with biomimetic patterns and nano-inclusions.
2:40 PM
Nucleation, Growth, and Grain Structure Control of Electrodeposited Graded Density Alloys: Michael McBride1; Donald Johnson1; Jamie Stull1; Enkeleda Dervishi1; Randall Edwards1; Daniel Hooks1; 1Los Alamos National Laboratory
Driven by an interest in dynamic high-pressure research, we are developing methods to create thick (mm) electrodeposited films of alloys with graded composition and density. We are designing deposition processes to dynamically control nucleation and growth to investigate correlations between grain structure and dynamic properties. Controlling nucleation and growth is critical to influencing ultimate grain structure in the deposit, so we have also determined and applied some basic nucleation and growth parameters for our systems. We present a study of electroplated films with compositional gradients and varied microstructures up to thicknesses of several mm for gold and silver, with discussion of other alloys in development. Constant potential and pulsed plating techniques were used to create a variety of grain structures, including high aspect ratio columnar grains. Microscopy was correlated with mechanical characterization of the films at several rates and scales, and related to nucleation and growth parameters. LA-UR-19-31897
3:10 PM
Reversible Electrochemical Mirror Devices Using Space Compliant Ionic Liquid Electrolytes: Holly Garich1; Danny Liu1; James Davis2; Morgan Tench3; Thomas Peng4; Jennings Taylor1; Timothy Hall1; Maria Inman1; 1Faraday Technology Inc; 2University of South Alabama; 3Tench Technology; 4AFRL
Reversible electrochemical mirror devices function through reversible redox reactions that alternate between deposition of a highly reflective thin metallic film and complete oxidation of the metallic film during the erasure cycle. For space-based applications, conventional organic electrolytes are unsuitable due to their vapor pressures and potential for evaporation if the cell seal is compromised. Room temperature ionic liquid electrolytes (RTIL) are an attractive alternative to these conventional systems due to their negligible vapor pressure in addition to their excellent chemical and thermal stability and their large electrochemical windows. The present work focuses on deposition and stripping of silver thin films from transparent electrodes a using RTIL electrolyte. Highly reflective and reproducible silver mirror formation using an air and moisture stable RTIL based electrolyte has been demonstrated, and use of pulse voltage deposition and erasure steps have promoted longer cycling lifetimes when compared to constant voltage operation.
3:30 PM
Electroplating Powder for Cold Spray Applications: Gwendolyn Bracker1; Elizabeth Hodges1; Madeline Scott1; Victor Champagne2; Robert Hyers1; 1University of Massachusetts; 2Cold Spray Innovations International
Cold spray is a processing technique in which powder particles are accelerated toward a substrate on which they deposit and build a wrought coating. In this process it is essential to balance the velocity of the particle, the properties of the particle, and of the substrate; otherwise, the particles may either fail to deposit or, may erode the substrate. Current work is exploring approaches that would allow for harder particles to be deposited on the surface of more ductile substrate without eroding the substrate. One approach to accomplish this is electroplating a softer coating on the hard powder. However, electrodeposits readily form a continuous layer binding the particles into a matrix, rather than uniformly coating the powders. A novel approach to electroplating has been successful with several different combinations of coatings and powders. This work will present new results on this work.
3:50 PM
Non-Linear Through-Hole Fabrication by Electrochemical Machining: Danny Liu1; Brian Skinn1; Andrew Moran1; Stephen Snyder1; Mike Horonzy2; Timothy Hall1; 1Faraday Technology, Inc.; 2Republic Anode Fabricators
Electrochemical machining (ECM) is an established manufacturing technique that possesses several advantages relative to traditional machining including: 1) applicability to hard and difficult to cut materials, 2) no tool wear, 3) high material removal rate, 4) smooth bright surface finish, and 5) production of parts with complex geometry. This talk will summarize recent efforts to demonstrate the feasibility of machining non-linear through-holes in metallic substrates via multi-step ECM. Results from initial experimental ECM activities will be presented, clearly demonstrating the capability to achieve non-linear holes. The potential for multiphysics modeling to provide accurate guidance on tool shape and ECM process parameters to achieve target machined geometries will also be discussed.
4:10 PM
Application of Artificial Neural Network and Statistical Modeling to Study Water Contact Angle of Ductile Iron: Iron-graphite Composite: Amir Kordijazi1; Hathibelagal Roshan1; Pradeep Rohatgi1; 1University of Wisconsin Milwaukee
The effect of graphite percentage, surface roughness, time, and droplet size on the water contact angle (CA) of ductile iron was examined. For design of experiment a full factorial design was utilized including 120 combinations of all factors and their levels. Contact angle values averaged 72°±11° with maximum of 92° and minimum of 46°. Multilayer Perceptron Neural Network Model was used to investigate the correlation between the predictor factors and CA. The results indicate the linear correlation between the predicted and observed values to be 0.756. The result also shows that the surface roughness is the most important predictor in CA variation followed by elapsed time, droplet size, and graphite percentage. In addition to ANN, multi linear and polynomial regression analysis were carried out. The result shows that CA increases by increasing surface roughness, graphite percentage, and time. This suggest that the ductile iron surface follow a quasi Cassie-Baxter regime.