Heterostructured and Gradient Materials (HGM IV): Tailoring Heterogeneity for Superior Properties: Heterostructured Materials III: Processing and Properties
Sponsored by: TMS Structural Materials Division, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Yuntian Zhu, City University of Hong Kong; Kei Ameyama, Ritsumeikan University; Irene Beyerlein, University of California, Santa Barbara; Yves Brechet, Grenoble Institute of Technology; Huajian Gao, Nanyang Technological University; Hyoung Seop Kim, Pohang University of Science and Technology; Ke Lu, Institute of Metal Research; Xiaolei Wu, State Institute of Mechanics, Chinese Academy of Sciences

Tuesday 8:30 AM
March 16, 2021
Room: RM 46
Location: TMS2021 Virtual

Session Chair: Andrea Hodge, University of Southern California; Megumi Kawasaki, Oregon State University; Nobuhiro Tsuji, Kyoto University


8:30 AM  Invited
Heterogenous Nanostructured Nickel Superalloy: Andrea Hodge1; 1University of Southern California
    This work explores the development of a heterogeneous nanostructured material synthesized via sputtering and by leveraging abnormal recrystallization. A sputtered nanotwinned Inconel 725 film with a heterogeneous distribution of stored energy was heat treated at 730°C, creating a unique combination of grain sizes and morphologies that were observed throughout the thickness of the material. Nanotwinned materials have been shown to exhibit exceptional mechanical and thermal properties due to a high density of coherent twin boundaries. As a result, there has been interest in investigating the effects of a nanotwinned structure on superalloys, which typically achieve strengthening through second phase or precipitate formation. From the experimental observations and the detailed analysis performed in this study, this methodology can be utilized to further expand the design space of current heterogeneous nanostructured materials

8:55 AM  
Interface Affected Plasticity in Accumulative Roll Bonded FCC/BCC Metallic Laminates : Rodney McCabe1; Matthew Schneider1; Jonathan Gigax1; Nan Li1; Thomas Nizolek1; John Carpenter1; 1Los Alamos National Laboratory
    Accumulative roll bonding (ARB) is a severe plastic deformation process used to produce bulk bimetallic laminates with average layer thicknesses ranging from hundreds of microns down to tens of nanometers. During deformation of ARB laminates, both during processing and post processing, the effects of bi-phase interfaces and co-deformation (or lack thereof) across these interfaces results in peculiar microstructures and properties. We use electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD) along with in situ straining SEM/TEM to examine the effects of the interface on microstructure evolution during deformation. During processing, grains directly abutting interfaces evolve orientation distributions differently than grains away from the interface. In addition, we show that ARB materials may fail due to void formation, shear banding, or kink banding depending on the average layer thickness and loading state. We examine how the interactions of deformation defects with interfaces contributes to these behaviors.

9:15 AM  
Mechanical Properties and Structural Stability of a Bulk Nanostructured Metastable Aluminum-magnesium: Megumi Kawasaki1; 1Oregon State University
    Separate metal disks of Al and Mg were mechanically bonded through high-pressure torsion (HPT) processing for equivalent strain of >2,000 under a compressive pressure of 6.0 GPa. Such high straining through the HPT processing synthesized a bulk nanostructured metastable Al with grain sizes of 35-40 nm in a state of supersaturated solid solution with the measured maximum Mg solubility of ~38.5 at.% via formation of Al-Mg intermetallic phases. The sample demonstrated uniaxial flow stresses of 1.3-1.5 GPa with an excellent plasticity by achieving high strain rate sensitivity of 0.036. An X-ray diffraction analysis estimated a high compositional microstrain of ~0.0202 due to the supersaturation of Mg in the Al matrix after processing. This increased to ~0.0274 after natural aging for 60 days due to the heterogeneous distribution of supersaturated Mg solutes without any nucleation of a second phase, thereby demonstrating a reasonable microstructural stability.

9:35 AM  Invited
Nucleation of New Deformation Modes in Nanostructured Metals: Nobuhiro Tsuji1; 1Kyoto University
    Twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) are well known effects to enhance strain hardening leading to both high strength and large tensile ductility. Since thin twins and hard martensite evolve,, respectively, during deformation, it is possible to consider that the microstructures become dynamically heterogeneous in TWIP and TRIP. From this standpoint, the author would like to show that new deformation modes, such as deformation twins, martensite, and abnormal slip systems, may nucleate from grain boundaries to realize both high strength and large ductility in metallic materials having recrystallized ultra fine grained structures.

10:00 AM  Invited
Solid-tsate Additive Manufacturing of Heterostructured Materials via Additive Friction Stir Deposition: Hang Yu1; 1Virginia Polytechnic Institute and State University
    Heterostructured materials are a new class of structural metals that exploit the incompatible plastic deformation between the mesoscopic soft and hard zones to implement unprecedented mechanical properties, most remarkably, the synergy of strength and ductility. To date, the manufacturing of heterostructured materials has mainly relied on traditional processing routes, such as accumulative roll bonding. In this talk, I introduce a new manufacturing strategy using additive friction stir deposition, which is an emerging solid-state additive process that integrates the friction stir principle with material feeding. By engineering the feed material, we are able to additively manufacture heterostructured materials that consist of mesoscopic zones with predefined volume fractions and controllable complex geometries in 3D. The microstructure of each mesoscopic zone is governed by continuous or discontinuous dynamic recrystallization and can be tailored via process control. Therefore, this strategy offers a vast design space for both the mesostructure and microstructure of heterostructured materials.

10:25 AM  
Optimizing Wear and Corrosion Resistance of Metallic Multilayers through Atomic-scale Design: Wenbo Wang1; Wenjun Cai1; 1Virginia Polytechnic Institute and State University
    Nanostructured metallic multilayers (NMMs) offer great opportunity to simultaneously improve wear and corrosion resistance of metals. In the present work, the wear, corrosion and tribocorrosion resistance of nanostructured metallic multilayers (NMMs) of Al/X (X= Mg, Cu, and Ti) were evaluated through experiments, finite element simulations, and density functional theory calculations. Transmission electron microscopy of deformed and degraded sample surfaces showed characteristic different deformation and degradation mode of all samples, governed by the synergistic effects of the mechanical and corrosion properties of the constituting materials. A finite element based computational model was developed to study the effects of constituting material on the material loss rate under various external mechanical and chemical loads. Finally, density functional calculations provide further insight on the material selection and design criteria for metallic multilayers toward enhanced performance under extreme environment.