Advanced Materials for Harsh Environments: Session II
Sponsored by: ACerS Electronics Division
Program Organizers: Navin Manjooran, Solve; Gary Pickrell, Virginia Tech
Monday 2:00 PM
October 10, 2022
Room: 333
Location: David L. Lawrence Convention Center
Session Chair: Bai Cui, University of Nebraska Lincoln; Navin Manjooran, Chairman, Solve; Gary Pickrell, Virginia Tech
2:00 PM Invited
In Situ X-ray Diffraction during Simulated Hot Isostatic Pressing of Additively Manufactured Inconel 625: Darren Pagan1; Rachel Lim2; Timothy Officer3; Tony Yu3; Yanbin Wang3; 1The Pennsylvania State University; 2Pennsylvania State University; 3Argonne National Laboratory
Hot isostatic pressing (HIP) is a common post-processing step for many additive manufacturing techniques to minimize the porosity commonly present in the as-built condition. However, secondary heat treatments used to the attain a target microstructure (including specific grain size, texture, and precipitate size) often negate the effects of the HIP process. As such, efforts are underway to combine the HIP process with standard heat treatments in a single processing step to enable both porosity minimization and microstructure optimization. To help accelerate processing route design, in-situ X-ray diffraction capabilities previously developed to understand subsurface rock deformation have been adapted to simulate HIP conditions and monitor bulk microstructural evolution in situ. To demonstrate this capability, recrystallization kinetics are quantified from X-ray diffraction data gathered during simulated HIP performed on as-built Inconel 625 produced using laser powder-bed fusion.
2:40 PM
High Temperature Irradiation Resistant Thermocouples for In-Pile Temperature Sensing: Scott Riley1; Kyle Holloway1; Richard Skifton2; Brian Jaques1; 1Boise State University; 2Idaho National Laboratory
The high temperature and irradiation resistance of niobium, molybdenum, and their alloys make them candidates for applications within nuclear reactors. The INL has developed thermocouples composed of doped niobium and doped molybdenum thermoelements, an alumina insulation, and a sheath made of niobium or its alloys. These thermocouples are projected to be used in GEN IV nuclear reactors. However, to stabilize the generated EMF signal during extended operation and use, the thermocouples undergo a preliminary heat treatment above the maximum service temperature. Herein, a study was conducted to evaluate the impact of the stabilization heat treatment on the microstructure, chemical stability, and electrical properties of the thermoelements to elucidate a mechanistic understanding of the stabilization event. The doped niobium thermoelement recrystallized and a Nb3P phase formed during the stabilization heat treatment. The impact of the stabilization heat treatment on the Seebeck coefficient and resistivity of the thermoelements will also be discussed.
3:00 PM
Integrating Multimodal Corrosion with Correlative Microscopy Across Multiple Lengthscales: Sridhar Niverty1; Rajib Kalsar1; Lyndi Strange1; Venkateshkumar Prabhakaran1; Ramprashad Prabhakaran1; Colin Campbell1; Benjamin Legg1; Vineet Joshi1; 1Pacific Northwest National Laboratory
Corrosion in light metal alloys is complex due to the simultaneous interaction of variables such as chemical composition, microstructure, corrosive environment (composition, pH), and temperature. It is also vital to understand how each of these factors contribute towards corrosion at multiple length scales. In this talk, we will discuss about the combination of multimodal corrosion with multiscale imaging to probe the corrosion behavior of light metal alloys. Using examples of joining of Al alloys and coatings for corrosion protection of Magnesium alloys, we will elaborate on the application of bulk and local electrochemical methods with ex situ and in situ imaging. This approach has yielded several interesting insights into the role of metallurgical phases and microstructural defects that contribute to local and global corrosion damage. Finally, the role of these multimodal electrochemical analyses in guiding corrosion mitigation will be discussed.
3:20 PM
Investigation of Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning Assisted X-ray Microscopy: Hrishi Bale1; Maadhav Kothari1; Sebastian Krauss1; Michael Phaneuf2; Johnathan Legget3; Simon Gray4; 1Carl Zeiss Microscopy; 2Fibics Incorporated; 3Rolls Royce; 4Cranfield University
Single crystal Ni superalloys are typically used in power generation and aviation applications due to their unique properties. Recently, incidents of failure due increased temperature around root blade regions has caused Type II hot corrosion leading to cracking in blade roots resulting in catastrophic failure. Understanding the failure mechanism and crack characterisation is vital in solving this industrial issue. Here we demonstrate a unique workflow of characterization using X-ray microscopy aided with deep-learning based algorithms for data reconstruction and segmentation, combined with FIB-SEM and electron microscopy in order to characterize cracks and crack tips developed during stress corrosion cracking.By extracting the fracture tip, both crystal plasticity and crystal deformity can be studied in detail resulting in orientation tomography of the corroded region of stress. Combining this correlative workflow we are able to demonstrate a unique technique in C-ring analysis and identifying structural defects not visible using typical microscopy techniques.
3:40 PM Break
4:00 PM
Isothermal Oxidation Behavior of Pack-Cementation Coated Three-phase Mo-Nb-Si-B Alloys: Liam Wood1; John Perepezko1; 1UW-Madison
The presence of the Mo(ss) and Mo5SiB2 (T2) phases in Mo-Si-B alloys is important for their structural and oxidation performance. In Mo(ss) + Mo3Si + T2 three-phase alloys, the addition of Nb destabilizes the Mo3Si phase in place of the more desirable Mo5Si3 (T1) phase. Pack-cementation Si:B coatings have been shown to improve the oxidation behavior of Mo-Si-B alloys but have not been tested on Mo-Nb-Si-B alloys. In this study, the isothermal oxidation behavior of Mo-Nb-Si-B alloys is examined by TGA at temperatures between 700°C - 1300°C. In the uncoated state, Mo-Nb-Si-B alloys outperform Mo-Si-B alloys by a factor of 3. With the pack-cementation Si:B coating, the mass change of the Mo-Nb-Si-B alloy is lowered to about -5 mg/cm2 after 50 hours at 1100°C, even with the presence of some Nb2O5 within the aluminoborosilica layer. The incorporation of an oxidation resistant coating advances the structural applications of Mo-Nb-Si-B alloys.
4:20 PM
JHU/APL’s Science of Extreme and Multifunctional Materials Program: Materials Research with Mission Intent: Morgana Trexler1; Leslie Hamilton1; Michael Brupbacher1; Steven Storck1; Erin LaBarre1; Nicholas Pavlopoulos1; 1The Johns Hopkins University Applied Physics Laboratory
From the the ocean, to the Arctic, to outer space, the Johns Hopkins University Applied Physics Laboratory (JHU/APL) researchers create materials that enable new capabilities in extreme environments. Leveraging advanced chemistry, materials science and computational tools across a variety of areas, we are inventing the future of research in extreme materials, materials design, synthesis and manufacturing, materials characterization, and multifunctional materials. This talk will provide an overview of JHU/APL’s materials research, which targets solutions for mission-driven technical challenges, creating materials that enable new capabilities for extreme environments. Specific topics will include the development of tailored additively manufactured alloys that mitigate corrosion, novel coatings that prevent icing in extreme cold, and thermal protection coatings that enhance survivability during hypersonic flight.
4:40 PM
New Strategies for Designing Colloidal Inks for Additive Manufacturing of UHTCs: Julia Goyer1; Carolina Tallon1; 1Virginia Tech
Increased shaping capacity for Ultra-High Temperature Ceramics (UHTCs) is paramount to their desired use in thermal protection systems for hypersonic vehicles. Through understanding of colloidal processes such as gelcasting and slip casting, an array of colloidal inks can be designed for ceramic additive manufacturing. This work compares inks that solidify by different mechanisms such as solvent evaporation, chemical curing, or yield stress rheology, and modeled the rheological behavior upon deposition. Layer adhesion and in-layer homoegeneity have been compared in addition to differences in green properties between additive and colloidal routes that utilize identical formulations. Colloidal routes using Zirconium Diboride have achieved >60% green density, and in gelcasting, showed a compressive green strength above 4 MPa, an order of magnitude increase compared to slip casting. The combination of advanced additive manufacturing ink development with different consolidation mechanisms has the potential of opening up new avenues for more cost-effective manufacturing of UHTCs.