Bulk Metallic Glasses XX: Poster Session
Sponsored by: TMS Structural Materials Division, TMS: Mechanical Behavior of Materials Committee
Program Organizers: Robert Maass, Federal Institute of Materials Research and Testing (BAM); Peter Derlet, Paul Scherrer Institut; Katharine Flores, Washington University in St. Louis; Yonghao Sun, The Chinese Academy of Sciences; Lindsay Greer, University of Cambridge; Peter Liaw, University of Tennessee
Tuesday 5:30 PM
March 21, 2023
Room: Exhibit Hall G
Location: SDCC
J-78: A Study of Ideal Glass State via High Entropy Metallic Glasses: Ji Young Kim1; Geun Hee Yoo1; Jung Soo Lee2; Hye-Jung Chang3; Jinwoo Hwang4; Eun Soo Park1; 1Seoul National University; 2Seoul National University / Inha University; 3Korea Institute of Science and Technology; 4The Ohio State University
In the field of metallic glasses, the ideal glass state has attracted special attention because it is expected to have the characteristic of high mechanical strength based on its unique atomic structure. The unique structure is characterized by high diversity in local structure, which means that it is not dominated by particular motifs. Even though it is suggested that mixing a large number of elements with different atomic sizes is a way to design ideal glass, there is a lack of research on analyzing the ideal glass experimentally. In this study, we designed high entropy metallic glasses (HE-MGs) with 10 different elements to make the atomic structure close to the ideal glass state. Using these HE-MGs, we studied the various characteristics of ideal glasses. We expect that the results enhance the insight of the ideal glass state in terms of atomic structural characteristics, unique mechanical properties, and abnormal crystallization behaviors.
A Theoretical Framework for Predicting the Ultimate Strength of Metals: Nicolas Argibay1; Michael Chandross2; 1DOE Ames Laboratory; 2Sandia National Laboratories
Building on seminal work by researchers like Mott, who in 1948 provided a theoretical description of grain boundary sliding as a thermally-activated process, we present a general predictive model – with no fitting parameters – for the strength of metals. A physics-based description of the stress, temperature, and shear-rate dependent activated process of interfacial amorphization, i.e., the transformation of a partially-ordered structured to a highly-disordered or amorphous one, is shown to accurately describe the grain size dependent shear strength of pure metals and alloys in the ultra-nanocrystalline regime. More recent and ongoing work on the extension of this method to more complex metallic systems, including metallic glasses, high-entropy/multi-principal element alloys, and intermetallic compounds, will also be discussed.
J-79: Comprehensive Investigation of Glass Formation Behavior of Ni-based Binary Alloys Considering Thermodynamics and Kinetics: Min Kyung Kwak1; Heh Sang Ahn1; Wook Ha Ryu1; Eun Soo Park1; Myeong Jun Lee1; 1Seoul National University
Metallic glass(MG) differs from crystalline in that it can undergo superplastic or thermoplastic deformation due to glass transition. Glass transition, reflecting the average bonding nature of MG, occurs at different temperatures depending on the alloy composition. Interestingly, in binary MGs with a relatively simple atomic structure, the correlation between composition and glass transition temperature (Tg) can be quantitatively analyzed. Here we comprehensively show the glass transition behavior of Ni-Zr MGs depending on composition and heating rate. Continuous heating transformation diagrams were constructed for three eutectic compositions, based on detailed thermal analysis through continuous heating experiments in a wide range of heating rates up to 10^4 K/s via Flash DSC. Through this study, we clarified the glass transition kinetics of Ni-Zr binary MGs in a wide composition range. We anticipate our study to serve as a basis for predicting Tg of metallic glass, given the alloy composition and heating rate.
J-80: Evidence of Pre-crystallization Structures in a Zr-based Metallic Glass: Amlan Das1; Ruitao Zhao2; Eric Dufresne3; Yonghao Sun2; Robert Maass4; 1Cornell High Energy Synchrotron Source; 2Institute of Physics, Chinese Academy of Sciences; 3Advanced Photon Source, Argonne National Laboratory; 4Federal Institute of Materials Research and Testing (BAM), University of Illinois at Urbana-Champaign
Sub-Tg annealing of metallic glasses (MGs) causes structural relaxation and deterioration of mechanical properties but the underlying structural ordering towards crystallization is hard to assess. Here we show the formation of a well-relaxed MG, via a 0.84Tg anneal of an as-cast MG that shows an endothermic pre-Tg process via calorimetry and increased short range ordering (SRO) observed via autocorrelation of HRTEM images. Upon annealing at 0.91Tg, the well-relaxed MG quickly loses the endothermic pre-Tg process and the increased SRO. Continuation of 0.91Tg annealing results in the appearance of a post-Tg endothermic peak and increased SRO above the relaxed levels. Finally, annealing at 0.98Tg causes the crystallization onset to shift to lower temperatures, suggesting that the above-mentioned ordering processes foreshadow crystallization. Annealing is accompanied by x-ray photon correlation spectroscopy and calorimetry, tracking the atomic dynamics and the stored enthalpy (and structure) of the MG towards crystallization.
J-81: Investigation of Isothermal Crystallization Behavior of Zr-Cu-Ni-Al Metallic Glass with Enhanced Icosahedral Ordering via Flash DSC: Myeong Jun Lee1; Geun Hee Yoo1; Eon Su Kim1; Wook Ha Ryu1; Eun Soo Park1; 1Seoul National University
Many studies have shown that icosahedral phase is formed in Zr-Cu-Ni-Al metallic glass by introduction of certain elements (Ti, Nb, Ta, Mo, etc.). In our past study, we have developed a new composition of Zr-based metallic glass with icosahedral phase as primary phase by substituting Cu with TiNbTaMo high entropy alloy. At thermal analysis with differential scanning calorimetry, two exothermic peak indicating crystallization merge into single exothermic peak with increasing heating rate. This might be indicating the existence of double-nosed TTT-diagram with secondary nose in smaller time scale and higher temperature than primary I-phase nose, but when sample is quenched slower than critical cooling rate, only single I-phase precipitation was shown. By utilizing Flash DSC, a novel chip-based fast scanning calorimetry with extreme heating rate, we investigated isothermal crystallization behavior of Zr65Cu13Ni10Al10(TiNbTaMo)2 in large time/temperature range. We expect to clarify how crystallization sequence changes in our newly developed alloy.
J-83: Microstructure and Wear Properties of Novel Fe Metamorphic Alloy Manufactured by Thermal Spray Process: Yu-Jin Hwang1; Yong-Hoon Cho1; Gi-Su Ham2; Choongyun Paul Kim2; Kee-Ahn Lee1; 1Inha university; 2KOLON Industries
The fraction of amorphous phase can be a major factor in the properties of thermal sprayed amorphous coating material. New Fe-metamorphic alloy (Fe-MMA), which transforms to the amorphous phase during the thermal spray process, was designed and manufactured and its microstructure and wear properties were investigated. Amorphous phase and crystalline phase were confirmed as two main constituent phases of thermal sprayed Fe-MMA coating layer, and (Fe,Cr)2B precipitations (320nm average size) were uniformly distributed. Room temperature wear properties of thermal sprayed Fe-MMA were performed using a pin-on-disk test. The wear rate (mm3/Nm) of Fe-MMA was similar to the representative thermal sprayed cermets (Fe-MMA: 1.96x10-5, WC-12Co: 2.33x10-5, and WC-4Cr-10Co: 1.78x10-5). Coefficient-of-fraction curves of cermets showed 3 stages (increasing-decreasing-steady state) whereas thermal sprayed Fe-MMA represented steady-state without decreasing. Based on the results above, the wear mechanism of thermal sprayed Fe-MMA coating material was discussed related to the microstructure.
J-84: Tailoring Structure and Properties of Bulk Metallic Glass through a Laser-process and Thermomechanical Process: Geun Hee Yoo1; Tae Gyu Park1; Jin Yeon Kim1; Eun Soo Park1; 1Seoul National University
The critical cooling rate for glass formation restrict their use in structural application. So, many researches tried to overcome the limitation of their dimensions by using powder metallurgy process such as Spark Plasma Sintering (SPS). In the present study, we will report the fabrication of Zr-based BMG by laser additive manufacturing (laser AM) and structural and mechanical difference between specimens which is fabricated by various process (as-cast, SPS and laser AM) through synchrotron X-ray scattering, TEM and nanoindentation mapping. Moreover, we can tailor microstructure and enhance properties of AM MG through rejuvenation. Finally, we suggest that we can design unique structure of bulk metallic glass through additive manufacturing and this unique structure also give us a chance to tailor properties further.
Thermodynamic Analysis and Modeling of Novel Ternary Ni-Pd-S Bulk Metallic Glass-forming System: Maryam Rahimi Chegeni1; Wenhao Ma2; Sascha Sebastian Riegler1; Magnus Rohde2; Amirhossein Ghavimi1; Hans Jürgen Seifert2; Isabella Gallino1; Ralf Busch1; 1Saarland University; 2Karlsruhe Institute of Technology
In this work, an experimental and computational investigation into the thermo-physical properties of the novel ternary BMG-forming Ni-Pd-S system is carried out. The simplicity of the ternary Ni-Pd-S BMG-forming system in comparison to the commonly found quinary BMG-formers facilitates the application of the CALPHAD approach for the modeling of the underlying thermodynamics ruling the glass formation and the description of the thermodynamic functions of the amorphous phases. Extensive experimental quantitative specific heat capacity and crystallization studies (DSC, XRD and SEM) of various glass-forming compositions are performed to generate input data for the calculations and modeling of the undercooled liquid. Isothermal crystallization is experimentally studied to provide partial or complete TTT diagrams for different glass-forming compositions. Based on the viscosity data of the liquid phase and CALPHAD calculations of the driving force for crystallization, the interfacial energies between the liquid and the solid are estimated and compared to the existing models.
J-85: Using Machine Learning to Find Correlations of Structure Motifs with Metallic Glass States and Mechanical Properties: Suyue Yuan1; Paulo Branicio1; 1University of Southern California
Vacancies are ubiquitous defects in crystalline materials that are related to their electronic, diffusion, and mechanical properties. We use machine learning to study the local atomic configuration in metallic glasses (MGs) and discover two unique topological footprints, T5 and Q7, which resemble vacancies in crystals and contribute significantly to the short-range structural disorder in MGs. The T5 and Q7 refer to atomic Voronoi polyhedra with five triangular faces and seven quadrangular faces respectively. Their concentrations in MGs follow an Arrhenius relationship with temperature before melting, as accurate indicators of the glass transition. They also show strong correlations with the yield and failure of the MG during deformation. Furthermore, atoms centered in T5/Q7 polyhedra display larger local entropy, atomic volume, and smaller activation energy. The finding of T5/Q7 motifs provides missing insights to understand the local disorder and their intrinsic relationships with thermal as well as mechanical behavior of MGs.