Characterization of Minerals, Metals and Materials: Characterization of Electronic and Magnetic Materials
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Jian Li, CanmetMATERIALS; Mingming Zhang, Baowu Ouyeel Co. Ltd; Bowen Li, Michigan Technological University; Sergio Monteiro, Instituto Militar de Engenharia; Shadia Ikhmayies; Yunus Kalay, Middle East Technical University; Jiann-Yang Hwang, Michigan Technological University; Juan Escobedo-Diaz, University of New South Wales; John Carpenter, Los Alamos National Laboratory; Andrew Brown, Devcom Arl Army Research Office
Thursday 8:30 AM
February 27, 2020
Room: Theater A-5
Location: San Diego Convention Ctr
Session Chair: Shadia Ikhmayies, Al Isra University; Andrew Brown, Army Research Laboratory
8:30 AM
Using Thermo-Calc Software to Produce the Phase Diagram of Zn-Te System: Shadia Ikhmayies1; 1Al Isra University
The phase diagram of the Zn-Te binary system was recalculated using Thermo-Calc software 2019b and compared with that found in the literature. The obtained phase diagram shows five stable phases and six fields of two mixed phases, in agreement with published experimental results. The melting points of Zn, Te, and stoichiometic ZnTe were determined and compared with previous ones obtained by different authors. A monotectic reaction was found at monotectic temperature of 1479.14 K (1205.99 °C) and 59.369 Zn mole percent. A miscibility gap was found in the phase diagram between 59.369 and 97.2781 Zn mole percent above monotectic temperature. In addition, two eutectic reactions were observed at the Te and Zn terminals. Solubility of ZnTe in liquid Te and Zn was determined. These results are important for development of preparation methods of ZnTe the intermediate compound of this system, which is important for several industries including solar cells.
8:50 AM
Epsilon to Tau Phase Transformation in MnAl Alloys: Ozgun Acar1; Merve Genc Unalan1; İlkay Kalay2; Yunus Kalay1; 1Middle East Technical University; 2Çankaya University
Magnetic materials play a critical role in devices for the conversion, transmission and energy storage. There is a growing demand for NdFeB permanent magnets with high coercivity and magnetic flux. While magnets are increasingly dependent upon rare-earths (RE), there has been an effort to minimize or substitute their use. In this regards, we studied RE-free MnAl alloys. Magnetism in MnAl alloys derives from a ferromagnetic metastable tau-phase. In order to improve the magnetic properties, epsilon-to-tau transformation should be well established. In this study, we conducted microstructural, thermal and crystallographic analysis of this phase transformation in details. XRD studies were conducted in-situ using synchrotron radiation. Epsilon-to-tau transformation is found to be dependent on ordering of the epsilon-phase and can only proceed with epsilon-prime phase. As Mn content increases compositional ordering do not take place and stable phases form. The corresponding magnetic properties with respect to phase transformation characteristics will be discussed.
9:10 AM
Structural and Magnetic Characterization of Magnetic Nanostructures in C2V Thin Films Exhibiting the Anisotropic Dzyaloshinskii-Moriya Interaction: Michael Kitcher1; Tim Mewes2; Claudia Mewes2; Marc De Graef1; Vincent Sokalski1; 1Department of Materials Science and Engineering, Carnegie Mellon University; 2MINT Center/Department of Physics & Astronomy, University of Alabama
2D C2V magnetic systems exhibit both Rashba and Dresselhaus forms of the Dzyaloshinskii-Moriya interaction (DMI). Together with the unit cell’s asymmetry, they define the DM vector. The DMI in such systems is thus anisotropic and hybridized, potentially stabilizing a broad range of magnetic nanostructures. This work presents a Si/Ag/Pt/Co/Ni(110) multilayer thin film, as informed by experimental and computational studies, which we propose as a tunable [anti]skyrmion host. Semi-analytical modelling of bubble domains in thin-layered Co/Pt(110)–with varying DM vectors–supports stable Bloch-Néel and/or elliptical skyrmions and antiskyrmions. Using alternating gradient magnetometry and Fresnel mode Lorentz transmission electron microscopy, cross-tie walls are observed in single-layer films exhibiting in-plane uniaxial anisotropy. Furthermore, we discuss the structure of films with perpendicular anisotropy and micromagnetic simulations of the relevant nanostructures, focusing on their stability. X-ray and selected area electron diffraction measurements reveal predominantly hexagonal closed-packed Co(10.0) layers with stacking faults and a secondary face-centered cubic phase.
9:30 AM
Influence on the Structural and Magnetic Properties of the Pre-alloyed Gas-atomized Maraging Steel Powder During Mechanical Milling: Ganesh Varma Thotakura1; Ramasis Goswami2; Tanjore Jayaraman1; 1University of Michigan-Dearborn; 2Naval Research Laboratory, US
We investigated the influence on the structural and magnetic properties of gas-atomized maraging steel powder during mechanical milling. The as-received powder comprised, primarily, martensite phase (α) and traces of retained austenite (γ); the saturation magnetization (MS) and intrinsic coercivity (HCI), at 300 K, was ~176 Am2/kg and ~3 kA/m, respectively. Powders milled from 3 h to 8 h comprised nanocrystalline α; the MS and HCI ranged from ~164 - 169 Am2/kg and ~4.9 - 6.7 kA/m, respectively. Milling above 8 h formed austenite and extraneous intermetallic phases, reduced MS and increased HCI. The MS increased with the decrease in the temperature from 300 - 60 K, for both the as-received and milled powders. The thermomagnetic behavior of the as-received and the milled powders from 300-900 K was fairly reversible. The magnetic properties of as-received and powder milled for 5 h were better than the powder milled for 56 h.
9:50 AM Break
10:05 AM Cancelled
Precipitate Characterization and Evolution in Grain Oriented Electrical Steel During High Temperature Coil Annealing: Xukai Zhang1; Jamo Momand1; Stefan Melzer2; Winfried Kranendonk2; Gert H. ten Brink1; Bart J. Kooi1; 1University of Groningen; 2Tata Steel, IJmuiden
Precipitates in grain oriented electrical steel (GOES) are crucial for achieving the extraordinary microstructure with sharp Goss texture required for transformer cores with ultra-low losses. In this work, decarburized and nitrided GOES samples were annealed to different temperatures during high temperature coil annealing. Transmission electron microscopy (TEM) investigations show that three types of precipitates are present in GOES. Precipitates were investigated with high resolution TEM, high angle annual dark field (HAADF) scanning TEM and energy dispersive X-ray spectrometry elemental mapping. Two types of areas with high and low number density of intermediate-sized (Al,Si)N precipitates were observed with HAADF-STEM within an SEM, using an image-stitching function. The precipitate size evolution in both areas was separately assessed quantitatively. This new technique not only guarantees high resolution of the image, but also a large area, which is essential for statistical analysis of nanoscale precipitates with low number density.
10:25 AM Cancelled
Bending Fatigue Testing for Electronic Connectors: David Snyder1; Larry Wojnicz1; Michael Gedeon2; Chad Finkbeiner2; Chen Jidong3; 1Molex LLC; 2Materion Corp.; 3Ningbo Powerway Alloy Material Co.
Bending fatigue resistance is a significant topic in spring material selection and electronic connector design, yet the scope of available industry test methods for sheet metal is both limited and outdated. Further, while it is understood that test results are highly dependent on the conditions of sheet specimen fabrication, little information has been published on the topic. The state of bending fatigue testing for sheet metal is reviewed, with a focus on the method, scope and limitations of the approach outlined in ASTM B593. Results of a comprehensive evaluation of precision and bias in this test method across multiple test laboratories is presented. The impact of specimen fabrication (edge milling, blanking and photochemical etching) on stress state and test results is also presented. Gaps in test methods and data availability important to connector design, and proposals for enhancing sheet metal fatigue test methods will be discussed.
10:45 AM
Phase Diagram of In-P Binary System: Shadia Ikhmayies1; 1Al Isra University
Indium phosphide is the only compound in the In-P binary system, and it is a semiconducting material used in optoelectronics, microelectronics, and solar cells. Understanding the thermodynamic properties of this material is important for these applications. Phase diagram of the In-P binary system was determined at 1 bar pressure and temperature range 200-1400 K using Thermo-Calc 2019b Software, and compared with experimental and calculated ones found in the literature. There are four phases, and six fields of which are four mixed (double phase) fields. The melting points of In and P elements, and InP compound were determine and all reactions are determined too.
11:05 AM
Temperature Dependence of Elastic Properties of Beryllium: Boris Maiorov1; Jon Betts1; Sky Sjue1; Angus Lawson1; Albert Migliori1; 1Los Alamos National Laboratory
Beryllium has the smallest atomic radius of all metals. Despite having only four electrons, beryllium’s properties are far from conventional. In particular, beryllium possesses exceptionally high elastic constants and an extremely small average Poisson ratio. Considering its high melting point, transparency to X-rays, and low neutron absorption cross section, beryllium is a prime candidate for many applications. Because of its high sound velocity and difficulty to handle, only a few measurements of beryllium’s elastic moduli temperature dependence exist. We present the temperature-dependent elastic moduli of polycrystalline S-200-F Be obtained using resonant ultrasound spectroscopy. We compare our results against those from literature, some of which show contradictory results. Our experimental results are also contrasted with recent calculations based on state-of-the art models.