Advanced Characterization of High-temperature Alloys: Phase Evolution during Manufacturing and Service-induced Deformation: Advanced Characterisation of Deformation Mechanisms: Diffraction, NDA and Modelling Methods
Sponsored by: TMS Structural Materials Division, TMS: High Temperature Alloys Committee
Program Organizers: Katerina Christofidou, University of Sheffield; Benjamin Adam, Oregon State University; Stoichko Antonov, Max-Planck Institut für Eisenforschung GmbH; James Coakley, Chromalloy; Martin Detrois, National Energy Technology Laboratory; Paraskevas Kontis, Norwegian University of Science and Technology; Stella Pedrazzini, Imperial College London; Sophie Primig, University of New South Wales
Wednesday 9:00 AM
March 22, 2023
Room: 29D
Location: SDCC
Session Chair: Benjamin Adam, Oregon State University; James Coakley, University of Miami
9:00 AM Invited
Understanding Phase Evolution and Deformation in High Temperature Materials via In-situ/Operando Neutron Diffraction: Ke An1; 1Oak Ridge National Laboratory
Neutron scattering is a bulk average non-destructive material characterization of both morphological and crystallographic structures by probing materials and structures under either ex-situ or in-situ/operando conditions by its advances, such as sensitivity to light elements, transition metals, isotopes, nuclear and magnetic structure ordering, as well as deep penetration with complex sample environments, etc. While it is available in national large user facilities, the materials research of high-temperature alloys using neutron on material synthesis, lattice structure, phase transition, physical properties, and deformation mechanisms in extreme environments has become popular and complementary to materials science communities. We show here how new science opportunities in phase evolution and deformation are opened for high-temperature materials communities by the dedicated engineering materials diffractometer VULCAN at the Spallation Neutron Source by its high flux neutrons, wide detector coverage, rapid data acquisition, as well as accommodating large operando devices.
9:30 AM
Phase- and Orientation-specific Mechanical Response during High-temperature Deformation of a γ' Strengthened Ni-based Superalloy: Nitesh Raj Jaladurgam1; Stefanus Harjo2; Magnus Colliander1; 1Chalmers University of Technology; 2Japan Atomic Energy Agency
We use in-situ neutron diffraction to investigate the load redistribution between and within γ and γ’ at 650 and 730 °C as a function of particle size in a low γ’ volume fraction Ni-base superalloy, Haynes 282. We observe a complicated evolution of the load redistribution which depends on particle size, temperature, and crystallographic orientation. This is particularly evident during the necking phase of samples with coarse (200 nm) γ’ particles, where the gamma matrix showed strong orientation effects, and the load transfer from γ to γ’ was drastically affected by temperature. The observations indicate that the damage evolution (softening beyond geometric necking effects and micro-crack/pore formation) during high temperature deformation is strongly phase-dependent and anisotropic.
9:50 AM
Microstructure Evolution and Deformation Micromechanisms in Refractory High Entropy Superalloys: Muhammad Awais1; William Hixson1; Howard Stone2; Nicholas Jones2; Ke An3; Dunji Yu3; Raj Banerjee4; James Coakley1; 1University of Miami; 2University of Cambridge; 3Oak Ridge National Laboratory; 4University of North Texas
Refractory high entropy superalloys (RSAs) are being pursued heavily due to their high temperature capabilities with the goal of stabilizing a microstructure resembling the well-known γ-γ’ Ni superalloy microstructure but with a disordered bcc matrix (A2) strengthened by ordered bcc precipitates (B2). However, there is still a lack of understanding of these compositionally complex materials and fundamental knowledge regarding deformation micromechanics and precipitation pathways must be realized quickly to be able to use RSAs in future generation engines.Room temperature and elevated temperature in-situ elastic and plastic deformation neutron diffraction measurements have been performed in order to determine phase elastic constants required for simulation (e.g. precipitate evolution) and to examine the phase stability and fundamental strengthening mechanisms within an A2 + B2 microstructure alloys for the first time. Supporting transmission electron microscopy will also be presented.
10:10 AM Break
10:30 AM
In Situ High Energy Diffraction Investigation of the Dynamic and Meta-dynamic Recrystallization of Ni Base Superalloy Haynes 282: Emil Eriksson1; Olof Bäcke1; Yao Hu1; Magnus Hörnqvist Colliander1; 1Chalmers University of Technology
In situ high energy synchrotron diffraction measurements of the dynamic and meta-dynamic recrystallization of Ni-base superalloy Haynes 282 during hot compression have been performed. Samples were heated inductively and we investigated temperatures ranging from 1080 – 1120 °C, with strain rates 0.005 and 0.05 s-1 and strains between 0.1 to 0.5. All samples were also subjected to a 120 s static hold at target temperature directly after compression to investigate the meta-dynamic recrystallization of the partially recrystallized microstructures. To track the (m)DRX process we used a small beam size (0.4x0.4 mm), resulting in individual Bragg spots (corresponding to individual grains) being resolvable on the downstream area detector. This allowed emergence and evolution of recrystallized grains to be measured during the process. Compared to traditional microstructural investigations of interrupted compression tests, the current approach provides 0.1 s time resolution without sample-to-sample variations.
10:50 AM
Phase-Field Modeling of Rafting in Ni-Based Superalloys with a Varying Lattice Misfit: Jose Dominic1; Jean-Briac le Graverend1; 1Texas A&M University
Phase-field modeling for rafting in Ni-based superalloys commonly uses a constant lattice misfit, namely the natural lattice misfit. However, in reality, the lattice misfit is a constrained lattice misfit that evolves. A varying lattice misfit is implemented in a phase-field model and the effects on the rafting process are investigated during creep at 1100C.
11:10 AM
Continuum Scale Approach to Characterization and Modeling of Deformation Mechanisms in Haynes 244 Alloy: Thomas Mann1; Michael Fahrmann2; Marisol Koslowski1; Michael Titus1; 1Purdue University; 2Haynes Intl.
A recently developed high strength, low CTE, Ni-based superalloy, HAYNES® 244®, is strengthened through the distribution of a novel intermetallic phase, the γ´´´-Immm Ni2(Cr, Mo, W) phase. The presence of this phase enables complex deformation mechanisms over orders of magnitude of strain rates. From quasi-static tensile deformation to creep deformation, deformation twinning is observed to be the dominant mechanism. The origin of this deformation twinning mechanisms stems from the complex GSFE of the low symmetry body centered orthorhombic structure. By modeling the energetics of dislocation interaction using Density Functional Theory, incorporating these energies in mesoscale Phase Field Dislocation Dynamics modeling, and comparing to experimentally observed deformed microstructures, the complex deformation pathway can be elucidated. These techniques combine computational simulations and experimental validation through HR-(S)TEM and EBSD quantification. These techniques represent a continuum scale of modeling and characterization for determining unique deformation in novel alloys.
11:30 AM Concluding Comments