Heterostructured and Gradient Materials (HGM IV): Tailoring Heterogeneity for Superior Properties: Functional Heterostructured Materials
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
Wednesday 2:00 PM
March 17, 2021
Room: RM 46
Location: TMS2021 Virtual
Session Chair: Peter Anderson, Ohio State University; Jagannathan Rajagopalan, Arizona State University; Anding Wang, City University of Hong KOng
2:00 PM Invited
Shape Memory Alloys: Using Heterostructure-induced Defects to Train Thermo-mechanical Response: Peter Anderson1; Harshad Paranjape2; Sivom Manchiraju3; Michael Mills1; 1Ohio State University; 2Confluent Medical Technologies; 3Ansys, Inc.
Shape memory alloys rely on tuning of lattice parameters and nucleation/pinning sites to finesse desired properties. Austenite-martensite interfaces can move at substantial fractions of the speed of sound and inject remnant dislocation structure and residual stress that “train” the material. The stress-induced transformation can be "tamed" from a sharp, abrupt process to a smoother, more continuous, reversible one that evolves over a range of stress. These phenomena are studied using a relatively new phase field-finite element formulation that captures the dynamics of the phase transformation. The results show that moving austenite-martensite interfaces can literally "write-in" specific dislocation slip patterns that are signatures of the particular interface and its velocity. A comparison with high resolution TEM micrographs highlights the competition between transformation and plasticity at interfaces and its regulation by stress gradients.
2:25 PM
High Strength and Low Coercivity Cobalt with Three-dimensional Planar Defects Introduced by Heterogeneous Coherent Interface: Jian Song1; Guisen Liu1; Y. Liu1; J. Wang2; X. Zhang3; 1Shanghai Jiao Tong University; 2University of Nebraska-Lincoln; 3Purdue University
High strength and wear resistance are essential for the reliability of cobalt in magnetic data storage and other information media applications. However, increasing the strength of cobalt by numerous methods, such as grain refinement, is typically accompanied by increasing of coercivity and magnetic anisotropy. Here, we demonstrated a new strategy that can accomplish high strength without sacrificing magnetic property of cobalt by introducing heterogeneous copper/cobalt coherent interface. Microstructural analysis revealed that the local strains originated from the heterogeneous interface could introduce high density three-dimensional stacking fault intersecting networks (SFINs) into cobalt. These networks can stabilize the metastable face-centered cubic cobalt at room temperature, and leading to lower coercivity and higher mechanical strength. Moreover, we found that tailoring the density of SFINs is an effective approach to optimize such properties. This work may provide a new strategy for integrated performance optimization by interface design and strain engineering.
2:45 PM
Analysis of Inertially Dampened Structure in High Strain Rate Impacts: Trenin Bayless1; Jerome Downey1; 1Montana Technological University
A continuation of computational studies on structures consisting of highly varied internal material densities when subjected to extreme strain rates. A detailed characterization of sintered polyethylene semi-crystals with embedded high density tungsten carbide inserts of varied geometry was conducted in order to verify the results of an earlier computational study. Examination under high strain rates in high energy impacts reveal variability in materials properties based on density, geometry, and size of tungsten carbide inserts. The following study provides a path forward for the creation of both physical and computational analysis focused on heterogeneous composite designs. In the instance of high strain rate impacts, the appearance of stress fields act to redirect the kinetic energy of an impactor; producing substantial increases in overall impact resistance of the composite material when compared to pure polyethylene structures.
3:05 PM
Interface Engineered Tungsten Based Nanocomposites and Nanofoams for Harsh Environments: Daniel Kiener1; Mingyue Zhao1; Inas Issa1; Michael Wurmshuber1; 1University of Leoben
Interface engineering offers wide opportunities to tailor properties of nanostructured metals. We focus on topological and structural modifications of tungsten, namely nanocrystals, nanocomposites, and nanoporous foams. By controlling the constituents and interface states, we combine the beneficial properties of nanostructures, such as high strength, with the positive attributes of nanoporous foams in terms of weight reduction and radiation tolerance, demonstrating that these materials have great potential to satisfy the requirements for high performance materials that can endure harsh environments. Building on interface modified nanocrystalline W for enhanced ductility, a nanoporous tungsten modification, characterized by a continuous network of nanocrystalline tungsten ligaments and nanopores, was created on a bulk scale through a versatile processing route. The mechanical properties were investigated by in-situ small-scale deformation and fracture experiments and the elemental mechanisms governing the mechanical behavior elucidated. Furthermore, the resistance of this tailored material against irradiation damage will be addressed.
3:25 PM
Hydrogen Charging Behavior of Gradient Structured High-Mn Steels: Jung Gi Kim1; Hyun Joo Seo2; Jeong Min Park2; Seung Mi Baek2; Auezhan Amanov3; Chong Soo Lee2; Hyoung Seop Kim2; 1Gyeongsang National University; 2Pohang Univerisity of Science and Technology; 3Sun Moon University
Hydrogen embrittlement of high strength steel is one of the critical issue when attempting to prolong the material life for a practical use. Because of this reason, microstructural design for a prevention of hydrogen invasion is important to enhance hydrogen embrittlement resistance of materials. In the present work, ultrasonic nanocrystalline surface modification (UNSM) treatment at elevated temperature was conducted to the high-Mn steel. Both nanocrystalline layer and compressive residual stress at the surface region of the UNSM treated high-Mn steel not only provide additional strength, but also prevent hydrogen invasion on the surface that reduces hydrogen localization in the defects. These beneficial effects enhance the mechanical property in a hydrogen-containing environment of the UNSM-treated high-Mn steel. This result proves designing heterogeneous microstructure in high-strength steel can be a good strategy to improve both strength-ductility combination and prolonged life time in a hydrogen-rich environment.
3:45 PM
Effects of Constituent Properties on Propagating Stress Waves in Multiphase Composites: Avery Samuel1; Irene Beyerlein1; Frank Zok1; 1University Of California, Santa Barbara
Composites comprising multiple dissimilar phases have recently seen increased interest for high strain rate applications. During high rate loading, stress is non-uniformly distributed and travels in waves. The character of those waves within and when transferring between phases is dictated by the properties of the constituents. Here we discuss effects of constituent properties and mismatches in properties on the nature of propagating stress waves in multiphase materials. In particular, elastic wave speeds are found to be dominated by the major phase and mismatches in properties lead to stress transfer by shear between phases. Phase boundary discontinuities and plasticity introduce further complexities which can dramatically alter stresses as the waves interact with interfaces.