Bulk Metallic Glasses XIX: 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, Chinese Academy of Sciences; Lindsay Greer, University of Cambridge; Peter Liaw, University of Tennessee

Monday 5:30 PM
February 28, 2022
Room: Exhibit Hall C
Location: Anaheim Convention Center

Session Chair: Katherine Flores, Washington University; Robert Maass, BAM and UIUC

A-14: A Molecular Dynamics Study of the Evolution of Medium-range Ordering in Liquid Metals: Doguhan Sariturk1; Can Okuyucu1; Yunus Kalay1; 1Middle East Technical University
    Al-Rare Earth (RE) metallic glasses have recently attracted significant attention due to their high densities of primary devitrification products and unordinary devitrification behaviors. Our previous studies have shown that Al-RE (RE: Sm, Tb) glasses produced via melt spinning and DC magnetron sputtering have similar short-range orders. Nevertheless, their devitrification behaviors altered significantly due to medium-range ordered (MRO) structures. The pre-peak at lower q-region in total structure factor of Al-RE metallic glasses is attributed to the MRO. In this study, local atomic structures of Al90Sm10 binary metallic glasses and their liquid counterparts are investigated using molecular dynamics simulations. The evolution of medium-range order is tracked from well above the liquidus temperature down to room temperature. In addition, Voronoi cluster analyses, Warren-Cowley pair analysis, and fluctuation electron microscopy simulations are carried out to identify the medium-range order present within the undercooled and liquid Al90Sm10 system.

A-19: High Metalloid Containing Ti-based Metallic Glasses for Biomedical Applications: Baran Sarac1; Eray Yüce1; Florian Spieckermann2; Amir Rezvan1; Jürgen Eckert2; 1Erich Schmid Institute of Materials Science; 2Montanuniversität Leoben
    Ti-based metallic glasses have been recently considered an alternative material for dental implants and surgical devices due to their corrosion and wear resistance as well as high hardness and specific strength. However, one major problem of the previously developed bulk Ti-based metallic glasses is the high copper content which makes them potentially toxic because the transitions between Cu(II) and Cu(I) can result in the generation of superoxide and hydroxyl radicals. This study focuses on developing fully biocompatible novel compositions with no toxic and precious group elements but with high metalloid content, i.e. Ti50Zr30Snx(SiGeB)y and Ti40Zr40Snx(SiGeB)y where x = 2 or 5 at.% and y = 18 or 15 at.%, with high hardness and low Young’s modulus. Fully amorphous ribbons confirmed by X-ray synchrotron radiation has very much lower passive current densities compared to Ti-6Al-4V alloy in 0.9 wt.% NaCl solution at 37 °C corroborating their biocompatibility.

A-20: Investigating the Fundamentals of Incipient Spall via Bulk Metallic Glasses with Laser-driven Micro-flyer Experiments: Christopher Dimarco1; Ethen Lund2; Gavin Mackay1; Laszlo Kecskes1; Jan Schroers2; K.T. Ramesh1; 1Johns Hopkins University; 2Yale University
    The spall failure process occurs through the interaction of rarefaction waves during dynamic loading through a void nucleation and growth process. While spall failure has been thoroughly studied, our understanding of the theoretical underpinnings of this failure process is still limited. Typically, void nucleation is driven by microstructural features, such as precipitates and grain boundaries, and the stochastic nature of these features results in large variation in the spall response. In an effort to investigate the mechanisms that drives the void nucleation process, we seek to remove these traditional microstructural details by studying bulk metallic glasses (BMGs). These are the first to utilize laser-driven micro-flyer experiments, which, facilitates high-throughput capabilities (i.e. meaningful statistics). We focus on two challenges: (1) improving the laser-driven micro-flyer experiment to ensure high repeatability, fine-tuned parameter control, and low experimental error; and (2) measuring and understanding the spall response in a BMG sample.

A-22: The Mechanical Properties of Al-Tb Nanocrystalline Marginal Metallic Glass Composite: Can Okuyucu1; Doguhan Sariturk1; Tolga Ulucan2; Mohammad Abboud3; Amir Motallebzadeh4; Sezer Özerinç1; İlkay Kalay5; Yunus Kalay1; 1Middle East Technical University; 2Max-Planck-Institut für Kohlenforschung; 3Bilkent University; 4Koç University; 5Çankaya University
    Partial devitrification of the Al-Tb marginal metallic glasses results in anomalous nucleation rate of nanocrystals. The resulting nanocrystalline metallic glass composites are regarded as promising engineering materials with robust properties such as higher strength and elasticity. In this study, the shear band propagation and corresponding micromechanical properties in nanocrystalline metallic glass composites were investigated in detail. The nanoindentation hardness values of the fully amorphous and the nanocrystalline metallic glass composite specimens were found as 2.8 GPa and 4.3 GPa, respectively. In contrast, the elastic modulus values were 68 GPa and 92 GPa. The increase in elastic modulus in partially crystalline specimens is associated with fcc-Al nanocrystals dividing the amorphous matrix and thus causing a branching of the shear bands. The mechanisms of shear band propagation in fully amorphous and partially crystalline marginal metallic glass will be discussed according to nanoindentation, micropillar compression, and transmission electron microscopy results.