Environmental Degradation of Multiple Principal Component Materials: High Temperature Corrosion
Sponsored by: TMS Structural Materials Division, TMS: Corrosion and Environmental Effects Committee, TMS: Nuclear Materials Committee
Program Organizers: Wenjun Cai, Virginia Polytechnic Institute and State University; ShinYoung Kang, Lawrence Livermore National Laboratory; XiaoXiang Yu, Novelis Inc.; Vilupanur Ravi, California State Polytechnic University Pomona; Christopher Weinberger, Colorado State University; Elizabeth Opila, University of Virginia; Bai Cui, University of Nebraska Lincoln; Mark Weaver, University of Alabama; Bronislava Gorr, Karlsruhe Institute of Technology (KIT); Srujan Rokkam, Advanced Cooling Technologies, Inc.
Thursday 8:30 AM
March 3, 2022
Room: 201C
Location: Anaheim Convention Center
Session Chair: Mathias Galetz, Dechema
8:30 AM
Dynamic and Chemical Processes Associated with Deposit-induced Corrosion Testing at Elevated Temperatures: Preston Nguyen1; Brian Gleeson1; 1University of Pittsburgh
High-temperature interaction between environmental deposits and Ni-based superalloys is of significant importance to the durability of components in aero turbine engines. Recent results have shown that more thorough laboratory testing is needed to elucidate the effects of deposit wetting and consumption on Ni-based superalloys. The principal aim of this study was to investigate the wetting and reaction behavior of hot corrosion deposits on a Ni-based superalloy. For this study, the Na2SO4 deposit was studied due to its perceived ability to affect specimens downstream in the gas stream. The effect of SiO2 addition to the deposit was also studied.
8:50 AM Invited
Enhanced Oxidation Resistance of (Mo95W5)85Ta10(TiZr)5 Refractory Multi-principal Element Alloy up to 1300°C: Ranran Su1; Hongliang Zhang1; Gaoyuan Ouyang2; Longfei Liu1; Jun Cui2; Duane Johnson2; John Perepezko1; 1Department of Materials Science and Engineering, University of Wisconsin-Madison; 2Ames Laboratory, U.S. Department of Energy at Iowa State University
Refractory-metal-based alloys are a potential replacement for current nickel-based superalloys due to their excellent mechanical strength at extremely high temperatures. However, severe oxidation in a high-temperature working environment limits their application. To address this challenge, a two-step coating process (including a Mo precoat and a Si-B pack cementation) was applied to an innovative refractory multi-principal element alloy (RMPEA) (Mo95W5)85Ta10(TiZr)5. The coating is composed of an aluminoborosilica glass layer on top of an RMPEA-Si-B multilayered structure. The coating effectively protects the RMPEA from oxidation in high-temperature environments, as demonstrated by phase-stable operation at 10-20% higher temperatures over state-of-the-art systems without any forced-cooling system. This two-step Mo-Si-B coating method can be adapted to provide environmental resistance to a wide range of RMPEA.
9:20 AM
Investigation of Low Temperature Oxidation Behavior of MoNbTaW Thin Films: Robert Quammen1; Paul F. Rottmann1; Taohid Bin Nur Tuhser1; 1University of Kentucky
MoNbTaW is a promising refractory multi-principal element alloy (RMPEA) that has exhibited good high temperature phase stability in vacuum and exceptional high temperature mechanical properties—even surpassing those seen in Ni superalloys. This combination of properties makes this alloy appealing for a variety of high temperature applications. A major hurdle, however, is the need for good environmental stability. RMPEAs are known to have poor oxidation resistance and to date no work has been conducted in regard to the oxidation behavior of MoNbTaW. Therefore, in the current work, in air anneals of sputtered MoNbTaW films in the 200C - 400C range were conducted to study the low temperature oxidation behavior. Subsequent microstructural (SEM and TEM), compositional (EDS and XPS), and mechanical (nanoindentation) characterization were completed. From this a mixed, amorphous oxide scale with increasing thickness with respect to annealing temperature was observed which detrimentally impacted the mechanical properties of the films.
9:40 AM
Oxidation of Different High Entropy Alloys Under the Influence of Water Vapour: Mary-Lee Brückner1; Lukas Mengis1; Emma White1; Mathias Galetz1; 1DECHEMA-Forschungsinstitut
Multi-Principal Element Alloys (MPEAs) have drawn a lot of scientific attention recently due to their unique, sometimes record-breaking, properties. In this work, the oxidation behavior of FeCoCrNiMn with small modifications, exchanging Mn for Al, Cu, and Al + Cu was investigated between 600 - 800 °C in synthetic air, as well as in synthetic air + 10 vol.% H2O. Across all compositions substitution of Mn leads to a significant improvement in oxidation resistance. For FeCoCrNiCu, a local attack of Cu-rich phases was observed along with internal Cr2O3. This selective oxidation was inhibited by the addition of Al, which formed a protective Al2O3 layer in all compositions. FeCoCrNiAl formed different types of Al2O3 (α-Al2O3 and θ-Al2O3), while FeCoCrNiCuAl only exhibits corundum. Several effects of water vapor are also noted such as needle-like surface structures or an impact on observed nitridation.
10:00 AM Break
10:20 AM
Joining of FeCrAl Based Alloys for Lead Cooled Fast Reactor Applications: Brandon Bohanon1; Shuprio Ghosh1; Cemal Cakez1; Khalid Talaat1; Jake Noltensmeyer1; Md Mehadi Hassan1; Osman Anderoglu1; Keith Woloshun2; Stu Maloy2; Cetin Unal2; 1University of New Mexico; 2Los Alamos National Laboratory
The lead-cooled fast reactor (LFR) is a fourth-generation reactor design characterized by high temperatures and neutron dosage. Lead is also highly corrosive to structural alloys and can cause erosion at high flow velocities. Therefore, materials that can withstand this harsh environment must be studied for structural and system components. Ferritic alloys are promising candidates due to the high-temperature creep strength, resistance to damage from fast-spectrum neutrons, and the growth of protective oxide layers. However, there are limitations due to erosion and the joining of these materials into the complex geometries of system components. In this talk, mechanical property, and microstructural evolution of additively manufactured and conventionally joined FeCrAl based ferritic alloys before and after molten lead exposure at 500C will be presented. Corrosion testing was performed at 500˚C in lead flowing up to 3 m/s in the Lobo Lead Loop at the University of New Mexico.
10:40 AM
Optimization of Multicomponent Rare Earth Silicate Environmental Barrier Coating Properties: Mackenzie Ridley1; Kathleen Tomko1; David Olson1; Patrick Hopkins1; Elizabeth Opila1; 1University of Virginia
Environmental barrier coatings (EBC) for ceramic matrix composites serve multiple functions in the turbine engine environment, providing resistance to high-temperature steam and calcium magnesium aluminosilicate (CMAS) molten deposits. Multicomponent rare earth silicates enable reductions in thermal conductivity as well as stabilization of nonequilibrium polymorphs, tailoring of EBC thermal expansion and thermochemical stability. In this presentation, the high temperature steam resistance of a two phase (Sc,Nd,Er,Yb,Lu)2Si2O7 material, the CMAS resistance of the single phase (Sc,Nd,Er,Yb,Lu)2SiO5 counterpart, and thermal conductivity of both the disilicate and monosilicate materials are presented. Choice of rare earth constituents with a wide mass and size range reduces thermal conductivity, small lanthanide rare earth silicates improve steam resistance, and large rare earths improve CMAS resistance. Thermal expansion is found to obey a rule of mixtures. Simultaneous optimization of multiple coating properties is demonstrated with this (Sc,Nd,Er,Yb,Lu) silicate mixture.
11:00 AM Invited
Exploring Untapped Potential in High Entropy Alloys: Combinatorial Exploration in Corrosive Environments: Mitra Taheri1; 1Johns Hopkins University
HEAs hold the promise of superior mechanical properties, corrosion resistance, radiation tolerance, and many other properties. We have not yet been able to realize these attributes, partially due to the vast and untapped alloy space. High throughput have provided a path forward, but only recently has it effectively been linked to both synthesis and properties testing in a meaningful way. Here we present the assessment of combinatorial HEA films and related discovery of superior corrosion resistance of an otherwise mundane alloy. Our high throughput synthesis methods combined with careful interfacial analysis underscores the importance of combinatorial and multimodal exploration of not only large numbers of high entropy alloy families but “off-stoichiometric” alloys within the same family.