Advanced Materials for Harsh Environments: Session I
Sponsored by: ACerS Electronics Division
Program Organizers: Navin Manjooran, Solve; Gary Pickrell, Virginia Tech

Monday 2:00 PM
October 18, 2021
Room: A223
Location: Greater Columbus Convention Center

Session Chair: Gary Pickrell, Professor, Virginia Tech; Navin Manjooran, Solve

2:00 PM
Investigation of the Variables Affecting Hot Corrosion Test Results: Preston Nguyen¹; Brian Gleeson¹; ¹University of Pittsburgh
    Ni-based superalloys are crucial in the operation of gas turbine engines. Due to the interaction of environmental deposits and gases with high temperatures during operation, accurate laboratory-scale hot corrosion testing is needed to elucidate the effects of deposit, atmosphere, and temperature on the degradation behavior. The principal aim of this study was to investigate the effects of common hot corrosion test procedures on the results that are obtained. For this study, the effect of Na₂SO₄ wetting was studied for its ability to affect hot corrosion test specimens downstream in the gas stream. The effect of the addition of steam and SO₂ in the gas stream was also studied as testing variables.

2:20 PM
Now On-Demand Only - Characterization and High Temperature Electrical Properties of Brazed Joints of La0.8Sr0.2CrO3 with Nickel and Nickel Alloys: Zhengtao Yang¹; Javier Mena¹; Jordan Conte¹; Brian Jordan¹; Katarzyna Sabolsky¹; Kostas Sierros¹; Edward Sabolsky¹; ¹West Virginia University
    There are many new electronics and sensor technologies being developed that are based on refractory conductive ceramics, which require stable joints that interconnect the active electroceramic components to exterior signal collection and processing hardware. In this work,the electrically conductive strontium-doped lanthanum chromite (La0.8Sr0.2CrO3) was brazed to nickel and nickel alloys in argon using nickel-based brazes including AWS BNi-3.The effect of bonding temperature/time, braze thickness, application pressure, surface roughness, and braze characteristics were evaluated. The joint chemistry and microstructure were characterized by SEM/EDS, and the local mechanical properties were tested with the use of nanoindentation.The electrical resistivity of the constituents were measured individually using a four-probe resistance from 200-1200 ℃ in argon and air.The joint resistivity was resolved by completing similar four-probe resistance measurements of the metal-ceramic joint and deconvoluting the contribution of each through composite models. This approach is expected to enable seamless, robust, interconnections for high temperature, harsh environments.

2:40 PM
Determining the Effect of Aerospace Environments on the Corrosion Fatigue Performance of AA7085-T7451: Brandon Free¹; Sarah Galyon Dorman²; Jason Niebuhr²; Nathan Houser²; Jenifer Locke¹; ¹The Ohio State University; ²SAFE Inc.
    AA7085-T7451 is an aerospace grade aluminum alloy that can be susceptible to corrosion fatigue (CF) when exposed to cyclic loading in atmospheric environments that are often made up of surface electrolyte droplets formed from deliquesced salts. Changes in humidity and temperature may lead to changes in CF performance that may not be adequately predicted by traditional experiments conducted in full immersion. The goal of this work is to quantify the effect of complex aerospace environments on the CF crack growth rates (da/dN) in AA7085-T7451. Testing to date has shown that samples loaded with 300 μg/cm² of NaCl and exposed to 80% RH show a similar da/dN to samples that were fully immersed in 0.06 M NaCl. Further testing has shown that salt loads as low as 50 μg/cm² exhibit da/dN close to that of full immersion when tested in 80% RH. Effects of wet/dry cycling and temperature are under investigation.

3:00 PM
Economically Alloyed High-speed Steel for Knives of Feeder Feeders of Glass Forming Machines: Valeriy Mishchenko¹; Sergеy Sheyko¹; Vоlоdimir Tsyganov²; Olha Bolsun¹; Svitlana Mudra¹; ¹Zaporizhzhia National University; ²National University "Zaporizhzhia polytechnic"
    Studied the main causes of the destruction of the knives feeder feeders glass forming machines. The components of economically alloyed high-speed steel were optimized by regression analysis. Developed sparingly speed steel knife feeder feeders, with a minimum amount of tungsten, molybdenum and vanadium. Selected economical method of connecting the cutting part of the knife holder.