Integration between Modeling and Experiments for Crystalline Metals: From Atomistic to Macroscopic Scales III: Session I
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
Monday 8:00 AM
October 18, 2021
Room: B246
Location: Greater Columbus Convention Center
Session Chair: M Arul Kumar, Los Alamos National Laboratory; Nathan Mara, University of Minnesota
8:00 AM Invited
Now On-Demand Only - An Integrated Modeling-experiment Approach to Investigating Metallic Interfaces Containing 3D Character: Nathan Mara1; Justin Cheng1; Zezhou Li1; Shuozhi Xu2; Youxing Chen3; Jonathan Poplawsky4; Nan Li5; Irene Beyerlein2; 1University of Minnesota; 2University of California, Santa Barbara; 3University of North Carolina, Charlotte; 4Oak Ridge National Laboratory; 5Los Alamos National Laboratory
2-dimensional (2-D) sharp interfaces with distinct boundaries demarcating an abrupt discontinuity in material properties in nanolayered composites been shown to be responsible for enhanced behaviors such as strength, radiation damage tolerance, and deformability. However, 2-D interfaces have limitations with respect to deformability and toughness. 3-D interfaces are defined as heterophase interfaces that extend out of plane into the two crystals on either side and are chemically, crystallographically, and/or topologically divergent, in three dimensions, from both crystals they join. Here, we focus on the thermal stability and mechanical behavior of nanolayered Cu/Nb containing interfaces with 3-D character. Micropillar compression results show that the strength and deformability of Cu/Nb nanocomposites containing 3-D interfaces is significantly greater than those containing 2-D interfaces. We will present our recent results on deformation of such 3-D interfaces and structures, and describe their structural evolution mechanistically through the use of atomistic and mesoscale simulations.
8:40 AM
Modeling Slip Transmission across Interface Using Dislocation Dynamics Simulations: Aritra Chakraborty1; Abigail Hunter1; Laurent Capolungo1; 1Los Alamos National Laboratory
A comprehensive realization of material deformation behavior is incomplete without understanding the effect of dislocation interactions at the interface. These interfaces are either grain boundaries (polycrystalline metals) or phase boundaries (two phase alloys). A critical aspect of such dislocation-interface interaction is the phenomenon of slip transmission across the interface, that can significantly affect the overall deformation response of the material. Even though such interactions have been well-studied using atomistic simulations, there has been limited effort in modeling them using dislocation dynamics (DD). DD simulations are ideal in investigating such interactions at the nanoscale, and hence, serves as a critical junction in bridging information between atomistic and macroscopic length scales. This work aims to develop a robust model for slip transmission in the DD framework. Subsequently, we observe the effect of allowing slip transmission on the overall plastic behavior in polycrystalline metals, as well as, two-phase metallic nanolaminates.
9:00 AM
Confined Layer Slip in Nanolaminates: Effect of Interface Structure and Layer Thickness: Wu-Rong Jian1; Shuozhi Xu1; Yanqing Su2; Irene Beyerlein1; 1University of California, Santa Barbara; 2Utah State University
Confined layer slip (CLS) is a predominant dislocation-based deformation mechanism that describes how a moving dislocation is confined within nanoscale multilayers. Using molecular dynamics simulation, we investigate CLS with respect to three interfaces, including the biphase Cu/Nb incoherent interface, homophase Cu/Cu incoherent interface, and homophase Nb/Nb coherent interface. In particular for the last interface, we study the layer thickness effect on CLS. The results show that the CLS of dislocations can be significantly obstructed by the misfit dislocations within the incoherent interfaces, in particular when the intersection line between the glide plane of dislocation and the interface coincides with the misfit dislocation lines. In addition, the layer thickness effect on the critical stress for CLS in nanolaminated Nb can be well described by the Hall-Petch effect due to the absence of misfit dislocation within the interface and the dislocation distribution in the neighboring layers can affect the dislocation motions.
9:20 AM
An Investigation of the Effect of Grain Boundary Parameters on the Slip System Level Hall-petch Coefficient for Basal and Prismatic Slip Systems in Mg-4Al: Mohsen Taheri Andani1; Aaditya Lakshmanan1; Veera Sundararaghavan1; John Allison1; Amit Misra1; 1University of Michigan
Grain size strengthening, referred to more commonly as Hall-Petch effect, is a common strategy to improve the yield strength of alloys. This effect arises from grain boundaries (GBs) resistance to plastic deformation by inhibiting slip transfer across adjacent grains. This work aims to utilize a high-resolution electron backscatter diffraction technique coupled with a continuum dislocation pile-up model to quantify the barrier strength of specific GBs to basal and prismatic slip in Mg-4Al. We characterize this barrier strength by studying the dependence of basal/prismatic slip system-level Hall-Petch coefficients on some crystallographic metrics motivated by slip transmission criteria. Our results indicate that the angle between the two slip plane traces on the GB plane and the angle between the slip directions are most correlated to the basal/prismatic slip system level Hall-Petch coefficients. This study provides insights into the understanding of the role of GBs in the plasticity of Magnesium alloys.
9:40 AM
Investigating the Mechanical Properties of Grain Boundaries with Displacement Texture Analysis: Anqi Qiu1; Ian Chesser2; Elizabeth Holm1; 1Carnegie Mellon University; 2George Mason University
Isolated cylindrical grains in metallic systems shrink under curvature driving force at high temperatures. With molecular dynamics simulations, we observed the rotations of isolated cylindrical grains towards higher or lower initial misorientations along with the shrinking, depending on the initial misorientations and temperature, due to shear-coupling. In previous works, we have shown that the calculated mobility of a cylindrical grain boundary at finite temperature is wide-ranging with respect to initial velocity seeds, in contrary to the common belief that the mobility is constant. The rotation behavior also varies greatly with initial velocity seeds. Displacement texture analysis has previous been used to decipher shear-shuffling and min-shuffling patterns. In this work, we apply displacement texture analysis to examine the motions of cylindrical boundaries moving freely, under blocked motion, and under cyclic torque. This gives more insights into the motion mechanisms and mechanical properties of cylindrical grain boundaries.