Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales III: On-Demand Oral Session II
Program Organizers: Arul Kumar Mariyappan, Los Alamos National Laboratory; Irene Beyerlein, University of California, Santa Barbara; Levente Balogh, Queen's University; Caizhi Zhou, University of South Carolina; Lei Cao, University of Nevada; Josh Kacher, Georgia Institute of Technology
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 7
Location: MS&T On Demand
Session Chair: Deep Choudhuri, New Mexico Institute of Mining and Technology; D Biswas, IIT Kharagpur
Invited
Extension Twin Induced Strain Hardening and Texture Evolution in AM30 Alloy: Experiments and Crystal Plasticity Modelling: Somjeet Biswas1; 1India Institute of Technology Kharagpur
The AM30 Magnesium alloy is a potential candidate for the next-generation automobile and aerospace structural components due to its high specific strength and low density. Its usage will reduce carbon emission in the atmosphere and thus the environmental impact of motored vehicles. However, AM30 has low ductility at ambient temperature and possess high anisotropy owing to its hexagonal closed packed structure. Due to limited dislocation slip activities at ambient temperature, {101 ̅2}〈1 ̅011〉 extension twins (ET) play a predominant role during deformation. In this work, experimental investigation using ex-situ electron backscattered diffraction and viscoplastic self-consistent based all twin variant model were employed to decipher the strain-hardening behaviour, microstructure evolution, including volume fraction evolution of each ET-variant, and texture evolution during deformation in AM30. The integration of modelling with the experiments provided in-depth insight into the deformation behaviour.
Invited
An Integrated Numerical Approach to Investigate the Effect of Grain-scale Heterogeneities on the Anisotropy of Polycrystalline Metals: Kyung Mun Min1; Hyukjae Lee1; Heung Nam Han1; Myoung-Gyu Lee1; 1Seoul National University
A numerical approach integrating the crystal plasticity and phase field model is presented in this study. In the proposed computational modeling, in addition to the local slip activities of polycrystalline metals, the non-crystallographic shear band formation is formulated and implemented in the crystal plasticity finite element method. Then, the local inhomogeneity of microstructure including the shear band formation in the cold rolling process is simulated and its effect on the texture evolution during deformation and heat treatment is analyzed. The texture change in the annealing process is predicted by generalizing the strain energy release maximization model into the phase field model. The calculated rolling, recrystallization textures, and the anisotropic mechanical properties of the metallic sheets are compared with corresponding experiments for the validation of the proposed modeling.
Invited
Deformation of Lamellar FCC-B2 Nanostructures Containing Kurdjumov-Sachs Interfaces: Relation between Interfacial Structure and Plasticity: Deep Choudhuri1; Srivilliputhur Srinivasan2; Rajiv Mishra2; 1New Mexico Institute of Mining and Technology; 2University of North Texas
By coupling high-resolution transmission electron microscopy and molecular dynamics (MD) simulations we have investigated the deformation mechanisms prevalent in lamellar micro- structures containing soft fcc and hard bcc-ordered intermetallic B2, whose interfaces follow the Kurdjumov-Sachs (KS) orientation relationship. TEM/MD coupling indicated that the KS interface contained steps and ledges, with several steps exhibiting fcc-B2 lattice continuity between the {111}fcc and {011}B2. The KS-fcc(111) interfacial plane also contained periodically arranged 1/6<112>fcc partial dislocations with screw-like character, which were separated by extended dislocation “core-overlap” regions. We observed that the screw-like interfacial partials facilitated the KS interfacial sliding and strain accumulation at the interphase interfaces and reduced the yield strength of the composite material compared to a pure-fcc reference material. Deformation character also depended on B2 lamellae thickness: thinner B2 lamellae sheared via twinning to drastically lowered flow stress such that the flow-strength, while thicker B2 lamellae sheared via a slip-transfer mechanism.
Formation of {112 ̅2} Contraction Twins in Titanium through Reversible Martensitic Phase Transformation: Amir Hassan Zahiri1; Jamie Ombogo1; Lei Cao1; 1Universitiy of Nevada Reno
We report the discovery of a non-conventional {112 ̅2}twinning mechanism in a- titanium through reversible α→ω→α martensitic phase transformations. Specifically, the parent α-phase first transforms into an intermediate ω-phase, which then quickly transforms into a twin α-phase, leading to the formation of {112 ̅2}contraction twins. In addition, we prove that the reversible α→ω→α phase transformations follow strict orientation relations between the parent α-, intermediate ω-, and twin a-phases. Finally, we demonstrate that our mechanism agrees with classical twinning theory in the shuffle, shear, and conjugate twinning plane. This study reveals the important role of the intermediate w-phase in the twinning process, adding critical details to the existing mechanism of {112 ̅2}twinning.
Modeling the Composition of Primary Carbides in the System Ni-11.5Cr-5Co-3.6Al-4.5Ti-7W-0.8Mo-0.06C: Alexander Glotka1; 1Zaporizhzhia Polytechnic National University
Theoretical modeling of the thermodynamic processes of the release of excess phases that carried out using the CALPHAD method are presented, as well as a practical study of the structure and distribution of chemical elements in carbides, depending on alloying using SEM. It has been established that in carbides typical for the Ni-11.5Cr-5Co-3.6Al-4.5Ti-7W-0.8Mo-0.06C system, takes place a tendency to degeneration and phase reactions depending on the level of alloying with the given elements. The mathematical dependences of the influence of alloying on the temperature of precipitation (dissolution) of carbides and the change in the chemical composition of the alloy on the content of elements in carbides are established. The obtained dependences were experimentally confirmed using SEM on nickel-based superalloys.
A Microstructural Model for Creep-fatigue Damage in Grade 91 Steel: Ajey Venkataraman1; Andrea Rovinelli1; Mark Messner1; 1Argonne National Laboratory
Grade 91 is a ferritic-martensitic alloy with excellent high temperature properties up to about 600◦C. Grade 91 is likely to be used in future high temperature reactors, where quantifying and understanding creep-fatigue performance is important. While it is known that the interaction between creep and fatigue is important for long-life applications, the relative contribution of the two mechanisms is not self-evident. Further, the exact mechanism of creep-fatigue interaction is not known. The above questions are addressed in the present work in the form of a microstructurally-informed damage model to predict creep-fatigue performance of Grade 91. Unlike empirical extrapolation techniques, microstructurally-informed models relate the material behavior to underlying, physical, microstructural mechanisms. These models typically extrapolate with better accuracy away from the experimental database. An improved understanding of the creep-fatigue interactions could lead to more efficient microreactor component designs.
Design of an Austenitic Steel Weldment System Using ICME: Daniel Bechetti1; Paul Lambert1; Matthew Sinfield1; Charles Fisher1; 1Naval Surface Warfare Center, Carderock Division
Integrated Computational Materials Engineering (ICME) principles and methods have enabled accelerated development and transition of new materials in many industries. In order to establish and evaluate an ICME framework relevant to the design of naval materials, engineers at Naval Surface Warfare Center, Carderock Division and Naval Research Laboratory are engaged in a program to concurrently develop a base material and welding filler metal system using computational, statistical, and experimental methods. This presentation reports work to date on ICME-enabled investigations of heat affected zone (HAZ) and fusion zone (FZ) process-structure-property relationships in a novel austenitic steel system. Topics covered will include CALuation of PHAse Diagrams (CALPHAD) modeling of solidification behavior and HAZ microstructure evolution under the influence of welding thermal cycles. Experimental validation of simulation results will be reported, and use of validated models to optimize alloy chemistry will be discussed.
Phase-field Simulations of Translation of Grains in Strain-energy-driven Grain Growth: Guanglong Huang1; David Montiel1; Matthew Higgins1; Jiwoong Kang1; Ning Lu1; Ashwin Shahani1; Katsuyo Thornton1; 1University of Michigan
Recent experiments have identified unexpectedly large grain translations during non-isothermal annealing. Through phase-field simulations, we show that this phenomenon can be induced by dislocation density gradients between grains. For these simulations, we extended a phase-field model for grain growth that accounts for the contribution of stored strain energy due to dislocations. We approximate the initial dislocation density field as a weighted average of the dislocation density in each grain and simultaneously solve for the evolution of the grains and the dislocation density. Our results show that net grain translation is observed in grains with a medium dislocation density that grow, on one end, at the expense of adjacent grains of high dislocation density and are consumed, on the opposite end, by adjacent grains of low dislocation density. This effect reveals a complexity in the dynamics of microstructure evolution that cannot be described by conventional models of capillary-driven grain growth.