Additive Manufacturing: Mechanisms and Mitigation of Aqueous Corrosion and High-temperature Oxidation: On-Demand Oral Presentations
Program Organizers: Amir Mostafaei, Illinois Institute of Technology; Yashar Behnamian, University of Alberta; Bryan Webler, Carnegie Mellon University
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 1
Location: MS&T On Demand
High Temperature Oxidation Behavior of Additively Manufactured ZrB2-30vol%SiC in CO2: Marharyta Lakusta1; Nicholas Timme2; William Fahrenholtz2; Jeremy Watts2; Gregory Hilmas2; David Lipke2; 1Missouri University of Science and Technolog; 2Missouri University of Science and Technology
ZrB2-30vol%SiC-based ceramics are attractive candidates for heat exchangers operating with supercritical CO2 working fluids at temperatures up to 1100oC and pressures up to 250 bar owing to their flexural strength up to 700 MPa and thermal conductivity exceeding 65 W/m·K at 1100°C in air. Due to long-term heat exchanger applications, material compatibility with the working fluid is of significant technological importance. There is no information about ZrB2-30vol%SiC oxidation in CO2. The main goal of this work is to compare the high-temperature oxidation behavior of ZrB2-30vol%SiC in CO2 to O2 atmospheres.Additively manufactured samples were pressureless-sintered at 2050oC. The oxidation was conducted under flowing CO2 in a thermogravimetric analyzer and microstructure characterization was performed to study oxidation kinetics. FactSage thermodynamics software package was utilized to assess phase stability diagrams and equilibrium compositions for the Zr-B-Si-C-O system. Results of these analyses and rationalizations of observed oxidation behaviors will be discussed.
Effect of Post Processing on the Corrosion Behavior of Selective Laser Melted Nickel Based Super Alloy in Acidic Environment: Mythreyi Venkataramana1; R Jayaganthan1; B K Nagesha2; 1IIT Madras; 2ISRO, GTRE
The present study investigates the corrosion behavior of selective laser melted Inconel 718 subjected to post processing. The printed samples are post processed through the treatments such as single ageing, double ageing and shot peening. The surface topographical changes of the different specimen conditions were measured by a non-contact surface profilometer. Optical and scanning electron microscopic imaging revealed the presence of multiple phases evolving during the selective laser melting and the two heat treatments. Potentiodynamic polarization and electrochemical impedance spectroscopy tests were conducted in an acidic environment to examine the corrosion behavior and to correlate with the effects of post processing treatments. The post corrosion imaging was carried out to determine elemental distribution in the pits. This work substantiates the electrochemical mechanisms governing the degradation behavior of selective laser melted and post processed Inconel 718 in acidic environment.