Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships: Poster Session
Sponsored by: ACerS Basic Science Division
Program Organizers: Shen Dillon, University of California, Irvine; Wolfgang Rheinheimer, University of Stuttgart; Catherine Bishop, University of Canterbury; Ming Tang, Rice University; John Blendell, Purdue University; Wayne Kaplan, Technion - Israel Institute Of Technology; Melissa Santala, Oregon State University
Monday 5:00 PM
October 10, 2022
Room: Ballroom BC
Location: David L. Lawrence Convention Center
E-2: Effect of Interfacial Microstructure on Tensile Property and Fracture Behaviour of Bicrystal and Polycrystal Fe/Ni Interface: Sien Liu1; Shoichi Nambu1; 1The University of Tokyo
The control of interfacial toughness is important in layered structure, where bicrystal and polycrystal interfaces have different deformation behaviour. Previous studies reported the presence of grains in interfacial region, but in-depth understanding on those grain boundaries (GBs) has been restricted by the grain size limitation of experimental method. In this study, we fabricated micro-size Fe/Ni bicrystal and polycrystal interfaces by solid state compressive bonding method to investigate the effects of grains in interfacial region on interfacial property and fracture behaviour. The results of micro-size uniaxial tensile test revealed that bicrystal interfaces show relatively higher bonding strength. In polycrystal interfaces, the lower energy release rate hinders instant fracture behaviour and hence, leads to enhanced interfacial toughness. Moreover, interfacial cracks were firstly observed at interface-GB junctions during tensile test, instead of high-stress-distributed notch spots. It is inferred that such junctions become weak spots and are attribute to the lower strength of polycrystal interfaces.
E-3: Fundamentals of Recrystallization in Binary Nb-Alloys: William Waliser1; M. Carl1; Kester Clarke1; Amy Clarke1; 1Colorado School of Mines
Nb3Sn superconductors are the most practical option for next-generation particle accelerator magnets. Recently, Hf additions to the base Nb alloy have be utilized to raise recrystallization temperatures above the Nb3Sn reaction treatment. This improves performance in the conductor by limiting the final Nb3Sn grain size. However, increased industry-wide Hf demand poses challenges for meeting future demands in particle accelerator projects, i.e. Future Circular Collider. Therefore, alternatives need to be identified for sustainability. A series of binary Nb-X alloys, including X=Ti, Zr, Hf, V, Ta, Mo, W, and Re, were fabricated and subjected to varying degrees of deformation. Static and dynamic recrystallization experiments were performed using the Gleeble thermomechanical simulator, and the resulting microstructure evolution was characterized with EBSD. Hardness measurements were also performed. This work expands upon the knowledgebase of how alloying elements affect microstructural evolution in Nb alloys for applications in superconductors and refractory multi-principal element alloys (RMPEAs).
E-4: Grain Boundary Energy Variation Related to the GBPD in Forsterite, Mg2SiO4, as a Function of Grain Size: Alexandra Austin1; Marina Sedlak1; Louise Rossett1; Sanae Koizumi2; Katharina Marquardt1; 1Imperial College; 2University of Tokyo
Forsterite is not only of interest for its high melting point (1890 °C), low thermal expansion, low dielectric permittivity (~70×10-12 F/m at 1 MHz), and excellent insulating properties at high temperatures but also as the dominating mineral in Earth’s upper mantle. We present measurements of the relative grain boundary energy for average grain sizes of 0.2, 3.8, 5.3, 9.4 µm and corresponding grain boundary plane distributions (GBPD). We use grain boundary groove profiles obtained from atomic force microscopy of thermally etched samples to extract the grain boundary energy anisotropy spread. The groove geometry was evaluated using a simplified form of Young's equation, approximating the surface energy as constant and neglecting the torque terms. The GBPD was obtained by measuring ~230.000 grain boundary segments from electron backscatter diffraction data. We will discuss the observed relative grain boundary energy variation and plane populations observed for these samples of different grain sizes.
E-5: Investigating the Relationship between Magnetic Barkhausen Noise, Microhardness, and Microstructural Development during Aging in HY-80 Steel: Michael Roberts1; Jason Schibler1; Charles D'Ambra1; Michele Manuel1; Thomas Krause2; Aroba Saleem1; 1University of Florida; 2Royal Military College of Canada
HY-80 Steel is a low carbon, high strength steel often used in submarines. High impact toughness ensures that hull breaches do not occur after mild collisions at deep depths; however, a phenomenon temper embrittlement can cause premature intergranular fracture leading to decreased impact toughness. Hence, developing a reliable technique to detect temper embrittlement is important. Magnetic Barkhausen Noise (MBN) has potential to be used for non-destructive analysis of HY-80. The current study investigated the relation between MBN, microstructure, and hardness of HY-80. MBN measurements were performed after heat treating samples at 525°C for varying holding times (0-336 hrs). Scanning electron microscopy and Vickers microhardness testing was also performed after each heat treatment. Microstructures were analyzed using image processing techniques and Computer Vision for quantitative analysis. MBN energy initially increased with holding time followed by a decrease, which was attributed to the change in the pinning density due to temper embrittlement.
E-6: Mesoscale Modeling for Time Dependent Grain Boundary Evolution: Lucero Lopez1; Meizhong Lyu1; Anqi Qui1; Elizabeth Holm1; 1Carnegie Mellon University
Analysis of grain boundary evolution is a critical step in understanding the relationship between microstructure and material properties. In experimental analysis we can see microstructure evolution in metals influences thermal-mechanical properties such as strength, hardness, and thermal and electrical conductivity, making the study of grain boundaries essential in Material Science. Computational simulations allow materials scientists to study the models that capture these phenomena. Our method is to compare three mesoscale models: Kinetic Monte Carlo, Probabilistic Cellular Automata, and Phase Field simulations for modeling grain growth and shrinkage, first in 2D and then 3D evolution. By comparing the uncertainty in grain lifetime in each of these models, the nature of grain evolution can be better understood. In particular, we begin to quantify how sensitive a microstructural outcome (grain disappearance) is to the details of the initial conditions. This helps bolster the relationship between grain structure and material properties.
E-7: Molecular Dynamics Study of the Deformation Behavior of Metallic Substrates under Shear/Vibration: Milad Khajehvand1; Henri Seppänen2; Panthea Sepehrband1; 1Santa Clara University; 2Kulicke & Soffa Industries, Inc.
Ultrasonic bonding (UB) encompasses a large subset of joining techniques that are used in microelectronics packaging, additive manufacturing, and battery welding. In UB, ultrasonic vibration is applied parallel to the interface of two metallic parts to form a bond between them. This research work aims to use molecular dynamics simulations and understand the atomic-scale nature of this process. For this purpose, contact is formed between two metallic substrates through a nanoscale phenomenon known as jump-to-contact (JC) and then, the deformation behavior of the system and the evolution of dislocations are analyzed when the interface is under shear/vibration. The effect of various parameters including the crystallographic orientation of substrates, the twist misorientation between them, and the initial interfacial gap size before the occurrence of JC is studied in this work. While (111)-oriented substrates are found to exhibit grain boundary sliding, the (001)- and (110)-oriented systems present multiplication of interfacial dislocations.
E-8: Theoretical and Machine Learning Studies of Grain Boundary Segregation and Solute Drag Effects: Malek Alkayyali1; 1Clemson University
The preferential segregation of elemental species to grain boundaries (GBs) affects many GB related phenomena. Of particular interest is the impact of GB segregation on GB migration. Experimental observations revealed that GB segregation mitigates grain coarsening and enhances the thermal stability of metallic alloys; however, most studies are focused on the thermodynamic aspect of GB segregation, and the role of the dynamic solute drag remains poorly understood. Herein, we develop a solute drag model in regular solution alloys, which captures the effect of solute-solute interactions and GB structure on boundary segregation. Machine learning tools employing artificial neural networks are utilized to explore the solute drag hyperspace. Furthermore, a universal solute drag-velocity relation is proposed that provides a robust fit for various metallic alloys. Overall, our solute drag treatment provides a predictive tool to rapidly explore the alloy design space for thermally stable metallic alloys.
E-9: Viscoelastic Bandgap and Thermal Transport in Inorganic-organic Nanolaminates: Rajan Khadka1; Pawel Keblinski1; 1Rensselaer Polytechnic Institute
In this work, using molecular dynamics (MD) simulations we characterize the viscoelastic response and thermal conductivity of Au-Molecular Nanolayer (MNL). In particular, oscillatory shear simulations deformation of nanolaminate reveal a high-damping-loss frequency band in the 77≤ υ ≤278 GHz. Our analysis indicates that this damping gap has an interfacial origin, can be manipulated by the strength of the interfacial bonding, and cannot be explained by weighted averages of bulk responses. We also found that the thermal conductivity of these organic-inorganic nanolaminates is controlled by the interfacial bonding strength. However, the effective interfacial thermal conductance in the nanolaminates with a ~ 2.4 nm “superlattice” period is about ~ 2.3 higher, regardless of the bonding strength, than the interfacial conductance of an isolated Au/MNL. junction.