Advances in Surface Engineering IV: Session II
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Surface Engineering Committee
Program Organizers: Arif Mubarok, PPG; Bharat Jasthi, South Dakota School of Mines & Technology; Tushar Borkar, Cleveland State University; Mary Lyn Lim, PPG Industries; Rajeev Gupta, North Carolina State University
Monday 2:00 PM
February 28, 2022
Room: 210C
Location: Anaheim Convention Center
Session Chair: Mohammad Umar Farooq Khan, Texas A&M University
2:00 PM
Effect of Test Temperature on Tribological Behavior of Laser Cladded Stellite 21 Coating on 350 Maraging Steel: Sougata Roy1; Niyanth Sridharan2; Ercan Cakmak2; Hamed Ghaednia3; Arup Gangopadhyay4; Jun Qu2; 1University of North Dakota; 2Oak Ridge National Laboratory; 3Ghering Group; 4Ford Motor Company
Current study was directed to characterize a Co-based Stellite 21 coating fabricated by laser cladding and study its tribological behavior at different temperatures, i.e., 25, 150, and 300o C. Detailed microstructure study on the 3D printed samples was conducted using XRD, SEM and EDS techniques. Friction and wear results of Stellite coated surfaces were compared against the substrate material 350 maraging steel. The Stellite coating showed significantly lowered friction than the maraging steel at all test temperatures. While the Stellite’s wear loss was higher than the steel in general, it retained wear resistance better at elevated temperatures. At a higher temperature, more material transfer from the coated surface to the counterface was observed. XRD based observation revealed FCC to HCP phase transformation due to heat treatment and during reciprocating wear tests which can be considered as the key factor in retaining the wear resistance at elevated temperatures.
2:20 PM Cancelled
Electrochemical Study of Stainless Steels in Diesel Exhaust Fluid (DEF) and Simulated Diesel Exhaust Acid Condensate Environments: Anusha' Chilukuri1; Michael Warwick1; Gaurav Argade1; 1Cummins Inc.
Electrochemical testing at room temperature was carried out in DEF and simulated acid condensate environments on 304L, 409 and 439 stainless steels. It was found that all the stainless steels are spontaneously passive in DEF solution at open circuit potential (OCP) with a large passive range of ~ 1000 mV above OCP. No evidence of pitting of the stainless steels was seen in this environment at higher anodic potentials. However, 409 showed active dissolution in acidic condensate solutions with corrosion currents higher than two orders of magnitude when compared to 439 and 304L. Electrochemical tests conducted on thermally exposed samples at 500°C for several hours indicated that the corrosion currents and the passivation currents in acidic condensate solutions increased with an increase in exposure times at the temperature. Similarly, the currents also increased when exposed to a higher temperature of 700°C with a relatively shorter exposure time of 5 hours.
2:40 PM
NOW ON-DEMAND ONLY - Evolution of Friction and Shear Deformation Induced Mixing of Graphene on Copper Substrate: Mayur Pole1; Shuang Li1; Kate Whalen1; Aditya Nittala1; Jinhui Tao1; Bharat Gwalani1; Keerti Kappagantula1; 1Pacific Northwest National Laboratory
Atomically thin graphene offers unusually high strength and lubricity.However, despite of its superior properties, graphene often gets worn out in macroscale tribological tests resulting in a highly refined tribo-layer. To evaluate the impact of graphene layering on copper substrate on lubricating performance upon sliding and shear induced mixing, we performed tribological experiments on mono and tri-layered graphene manufactured by chemical vapor deposition on copper foil. A sharp increase in the coefficient of friction (COF) attributed to rupture and smearing of graphene layer into copper substrate was seen. The COF of the copper/graphene samples remained lower than that of pure copper, suggesting that partially worn graphene can remain effectively lubricious at the macroscale. A multimodal characterization of the tribo-layer revealed a shear deformation-induced ultrafine two-phase grain-structure consisting of copper and graphitic domains. This study provides new insights on macroscale structure-property correlation of copper-graphene composites, with widespread structural and functional applications.
3:00 PM
Corrosion-resistant Yet Sacrificial Metallic Coatings with an Ability to Release Inhibitor on Demand: C.S. Witharamage1; M. Alrizqi1; A. Darwish1; A. Nieto2; Rajeev Gupta1; 1North Carolina State University; 2Naval Postgraduate School
We present highly corrosion-resistant yet sacrificial metallic coatings- two attributes that do not usually go hand in hand. The coating is a supersaturated solid solution of Al with corrosion-resistant alloying elements and was applied on commercial aluminum alloy AA2024-T3 using cold spray. The microstructure and composition of coatings are engineered to achieve high pitting potential and low corrosion current density along with a corrosion potential less noble than that of the substrate. This means that in any event of coating breakdown, the coating would corrode and prevent the substrate from corrosion. Alloy composition is chosen such that corrosion of coating releases chemical species that could inhibit corrosion by decreasing the cathodic efficiency of the substrate. The characteristics of the coatings can be controlled by changing the composition and microstructure of the metallic coating. We will present the corrosion behavior of coated specimens and corrosion mechanisms as investigated using a combination of advanced electrochemical and analytical techniques.
3:20 PM Break
3:40 PM
Finite Element Simulation for the Electropolishing of Niobium: Kaiwen Wang1; Wenjun Cai1; Hui Tian2; Charles Reece2; 1Virginia Polytechnic Institute and State University; 2Thomas Jefferson National Accelerator Facility
Niobium is a commonly used material to construct high-field superconducting radiofrequency (SRF) cavity. To achieve the required surface smoothness, the internal surface of the niobium cavities is often processed by electropolishing. It is extremely important to understand the electrochemical kinetics of the reactions happened at the surface, the Joule heating and heat transfer during the electropolishing process for different structured SRF cavities. In this work, finite element method was used to investigate the mechanisms of electropolishing by simulating the current distribution, oxide growth, concentration of ion species and Joule heating with the actual geometry of the niobium cavity considered. The model successfully predicts the difference in the resulting surface quality caused by geometry effect as well as different electropolishing parameters, which includes the applied voltage and the dimensions of the cathode. The model results provide better understanding of the electropolishing mechanisms of niobium for future cavity design and process control.
4:00 PM
Mapping the Nanomechanical Behavior of Refractory Alloy Nitride Coatings: Andre Bohn1; Yu-Hsuan Lin1; Justin Cheng1; David Poerschke1; Nathan Mara1; 1University of Minnesota
Nitride-based surface enhancement plays an important role in achieving desired tribological characteristics in many wear applications. While this technique is readily applied to various ferrous alloys, improved understanding of processing-microstructure-property relationships for nitridation of other principal components is necessary to develop comparable processes for emerging transition and refractory metal multi-principal element alloys. To provide the science base underpinning process design for these new alloys, we gas nitrided pure Ta, Hf, Mo, Zr, Ti, and Nb under varying nitrogen potentials and temperatures to probe the transitions between nitrogen dissolution into the alloy and nitride compound layer formation. We used Berkovich nanoindentation to map hardness and modulus as a function of local composition of nitrided regions before and after processing. These insights about the effect of processing on the thickness of the reacted and interdiffused regions can guide tuning of mechanical properties by manipulating surface nitride formation and subsurface nitrogen concentration.