Ultrafine-grained and Heterostructured Materials (UFGH XII): Microstructure, Mechanisms & Property II
Sponsored by: TMS: Shaping and Forming Committee
Program Organizers: Penghui Cao, University of California, Irvine; Xiaoxu Huang, Chongqing University; Enrique Lavernia, Texas A&M University; Xiaozhou Liao, University of Sydney; Lee Semiatin, MRL Materials Resources LLC; Nobuhiro Tsuji, Kyoto University; Caizhi Zhou, University of South Carolina; Yuntian Zhu, City University of Hong Kong

Tuesday 4:00 PM
March 1, 2022
Room: 262A
Location: Anaheim Convention Center

Session Chair: Cem Tasan, Massachusetts Institute of Technology; Hyoung Seop Kim, Pohang University of Science and Technology; Terry Lowe, Colorado School of Mines

4:00 PM  Invited
Heterostructured V-Ti-Ni Alloy Containing Superelastic Nano-precipitates: C. Tasan1; Jaclyn Cho1; 1Massachusetts Institute of Technology
    V-Ti-Ni alloys can develop a realm of interesting microstructures. The V45Ti30Ni25 (at%) alloy, for example, has a microstructure with superelastic TiNi and stable V-rich bcc phase (β) coexisting in multiple phase mixtures with each acting as matrix and precipitate. In this talk, we will discuss the design principles of this alloy and its interesting microstructure. Furthermore, using results of nanoindentation measurements and in-situ synchrotron and SEM tensile tests coupled with digital image correlation analysis, we will discuss the strain partitioning behaviors of the microstructural constituents, as well as their reverse transformation tendencies. These insights on multi-phase plasticity provide hints for improved damage-resistance in presence of a superelastic phase.

4:30 PM  
Mechanical Behavior of Heterostructured Fe Films with Precisely Defined Bimodal Architectures: Rohit Berlia1; Jagannathan Rajagopalan1; 1Arizona State University
    Heterostructured metals exhibit a superior combination of strength and toughness compared to homogeneous nanostructured and coarse-grained metals. However, our ability to robustly tailor the microstructure of such materials is still limited. Here we report a method to fabricate heterostructured metallic films with precisely defined architectures, wherein the size, volume fraction and spatial distribution of nanocrystalline (NC) and single crystal (SC) domains can be explicitly controlled. Using this technique, we synthesized bimodal Fe films with two architectures - SC and NC domains in series and parallel - and explored their stress-strain behavior. Furthermore, we also varied the loading axis with respect to the crystallographic orientation of the SC domains. Our results show that both the overall architecture and the slip geometry in the SC domains play a crucial role in determining the stress-strain response. These findings open up the possibility of systematically tailoring the mechanical properties of heterostructured metals.

4:50 PM  
Now On-Demand Only - Introducing Gradient Structure to a CrMnFeCoNi High-entropy Alloy for Superior Mechanical Properties: Nazmul Hasan1; Xianghai An1; Yuntian Zhu2; Xiaozhou Liao1; 1University of Sydney; 2City University of Hong Kong
    We explore how different gradient structures of an equiatomic CrMnFeCoNi high-entropy alloy (HEA) affect its mechanical properties. The alloy was processed using the rotationally accelerated shot peening technique. Varying processing parameters leads to different gradient hierarchical structures that subsequently change the mechanical behaviour of the material. Microstructures along the depth from sample surface were characterized using advanced electron microscopy. Mechanical properties were obtained using microindentation and uniaxial tensile testing. The quantitative contributions of different structural features including deformation twins and dislocations to the surface hardening were carefully investigated. Based on our study, an appropriate gradient structure profile is recommended for excellent combination of strength and ductility.

5:10 PM  
3D Heterostructures via Mechanochemical Reshuffling of Layered and Non-layered Metal Chalcogenides: Viktor Balema1; 1ProChem Inc. Rockford IL USA
     3D-heterostructures with incommensurate arrangements of well-defined building blocks are created using an unconventional synthetic approach comprising of mechanically facilitated “reshuffling” of layered transition-metal dichalcogenides [1,2], and non-layered rare-earth metal monochalcogenides [2]. The discovered solid-state transformations are directed by quantum interaction between chemically and structurally dissimilar solids toward atomic-scale ordering. In the case of MoS2 and HfS2 [1], the heterostructuring is energetically favorable over the formation of homogeneous nigh-entropy dichalcogenides [3]. Density-functional theory calculations validate experimental results. The obtained 3D-heterostructures show broad range of electron transport behaviors varying from metallic conductivity to indirect band gap semiconductivity. Finally, the presentations reviews current state of the art in the field of Mechanochemistry and highlights possible mechanisms of mechanochemical transformations. References: [1] I. Z. Hlova et al. Nanoscale Adv. (2021), Ahead of Print. [2] O. Dolotko et al. Nat. Commun. (2020), 11(1), 3005[3] I. Z. Hlova et al. Chem. Commun. (2018), 54(89), 12574