ORALS

SESSION: ManufacturingWedPM1-R4 Energy	Mamalis International Symposium on Advanced Manufacturing of Advanced Materials and Structures with Sustainable Industrial Applications
Wed Nov, 7 2018 / Room: Sao Conrado (50/2nd)
Session Chairs: Nikoloz Chikhradze; Session Monitor: TBA

14:25: [ManufacturingWedPM106]
Structure and Properties of MgB<sub>2</sub>- and MT-YBaCuO-based Materials Manufactured Under Pressure
Tetiana Prikhna¹ ; Michael Eisterer² ; Matt Rindfleisch³ ; Athanasios G. Mamalis⁴ ; Michael Tomsic³ ; Vitaliy Romaka⁵ ;⁰ ; Artem Kozyrev¹ ; Myroslav Karpets¹ ; Anton Shaternik¹ ; ¹Institute for Superhard Materials, Kiev, Ukraine; ²Atominstitut, Technische Universität Wien, Vienna, Austria; ³Hyper Tech Research, Inc., Columbus, United States; ⁴PC-NAE, Demokritos National Center for Scientific Research, Athens, Greece; ⁵Lviv Polytechnic National University, Lviv, Ukraine;
Paper Id: 121 [Abstract]

The influences of technological parameters (temperature, pressure, type of cladding), composition of precursor powders, and type of additions (Dy₂O₃, Zr, Ti, Ti-O, SiC, Nb) on the superconducting characteristics (transition temperature, critical current density, critical magnetic fields) of MgB₂ wires produced by Hyper Tech Research Inc. and of bulk materials synthesized under ambient, elevated, and high pressures in correlation with their microstructures, were studied. Microstructural observations are in good agreement with ab-initio modeling [1, 2]. The relevant pinning centers of Abrikosov vortices in MgB₂-based materials are oxygen-enriched Mg-B-O inclusions (or nanolayers) and inclusions of high borides MgBx. Their number and size depends on the synthesis parameters and dopants. Ti, Ta, and Zr bind hydrogen, make the formation of magnesium hydride impossible, and thus improve the mechanical characteristics bulk MgB2. Ti, Ta, Zr also affects the formation of higher borides, and Ti, Ta, Zr, SiC, TiC - on the redistribution of oxygen. The critical current density, jc of melt textured YBa₂Cu₃O₇-d (or Y₁₂₃)-based superconductors (MT-YBaCuO) depends on the perfection of texture and the amount of oxygen in the Y₁₂₃ structure, but also on the density of twins and micro-cracks formed during the oxygenation (due to shrinking of the c-lattice parameter). The density of twins and micro-cracks increases with the reduction of the distance between Y₂BaCuO₅ (Y₂₁₁) inclusions in Y₁₂₃. A high level of critical current density demonstrated MT-YBCO oxygenated under 16 MPa oxygen pressure and MgB₂ high pressure (2 GPa) - high temperature synthesized: jc (MT-YBaCuO) at 77 K was nearly 105 A/cm² in self-field and 103 A/cm² at 10 Т, and jc (MgB₂) at 20 K was 106 at 1 T and 103 A/cm² at 8.5 T. The MgB₂ wires with added Dy₂O₃ (4 wt.%, 100 nm) demonstrated Jc=11 kA/cm² at 20 K in 5 T and at 4.2 K in 12.5 T fields.

References:
[1] T.A. Prikhna, V.V. Romaka, A.P. Shapovalov, M. Eisterer, V. Sokolovsky, H.W. Weber, G.E. Grechnev, V.G. Boutko, A.A. Gusev, A.V. Kozyrev, W. Goldacker, V.E. Moshchil, V.B. Sverdun, T. Habisreuther, C. Schmidt, V.V. Kovylaev, V.E. Shaternik, M.V. Karpets, A.V. Shaternik, "Structure and Properties of MgB2 bulks, thin films, and wires", IEEE Trans. Appl. Supercond., vol. 27, Is. 4, 2017, pp. 1-5, DOI: 10.1109/TASC.2016.2638201.
[2] T. А. Prikhna, A. Р. Shapovalov, G. E. Grechnev, V. G. Boutko, A. A. Gusev, A. V. Kozyrev, M. A. Belogolovskiy, V. E. Moshchil and V. B. Sverdun, "Formation of nanostructure of magnesium diboride based materials with high superconducting characteristics", Low Temperature Physics, vol. 42, No 5, pp. 486-505, 2016.

SESSION: AdvancedMaterialsWedPM1-R6	4th Intl. Symp. on New and Advanced Materials and Technologies for Energy, Environment and Sustainable Development
Wed Nov, 7 2018 / Room: Guaratiba (60/2nd)
Session Chairs: Marina Nisnevitch; Session Monitor: TBA

14:50: [AdvancedMaterialsWedPM107] Invited
Hot Pressed Aluminum Dodecaboride- and Boron Carbide-based Ceramics
Tetiana Prikhna¹ ; Pavlo Barvitskiy¹ ; Viktor Moshchil¹ ; Vladislav Domnich² ; Fernand Marquis³ ; Myroslav Karpets¹ ; Sergey Dub¹ ; Semyon Ponomarov⁴ ; Richard Haber² ; ¹Institute for Superhard Materials, Kiev, Ukraine; ²Rutgers University, New Brunswick, United States; ³San Diego State University, San Diego, United States; ⁴Institute of Semiconductor Physics, Kiev, Ukraine;
Paper Id: 119 [Abstract]

The results of a structural and mechanical properties study of aluminum dodecaboride (a-AlB₁₂, AlB₁₂C₂, a-AlB₁₂-TiB₂-TiC)- and boron carbide (B₄C and B₄C-SiC)-based ceramics, hot pressed at 30 MPa, 1950 - 2240°C, and high pressure (2 GPa) as well as high temperature (1200-1400°C) sintered and synthesized, will be under discussion. The materials can be used as protective armor or constructional ceramics for nuclear power plants, additives to the boron-carbide-based materials, or as solid fuel, abrasives, explosives, etc. [1-5]. The materials were manufactured from a-AlB₁₂, AlB₁₂C₂, C nanopowders and B₄C, SiC, TiC micropowders. The preliminary mixtures of powders were prepared using high speed planetary activator. The a-AlB₁₂ powder with and without carbon additions can be sintered to the dense state of 1200-1400°C, 2 GPa, 1 h, while the hardness of the materials was not high (12.5-17.8 GPa at 49 N-load). The AlB₁₂C₂ nanopowder sintered at 1400°C, 2 GPa, 1 h contained 89 wt.% AlB₁₂C₂ and 11 wt.% of admixture Al₂O₃ (according x-ray diffraction study) and demonstrated hardness HV(49 N-load)=26.6-0.6 GPa, fracture toughness K_1<i>c</i> (49 N)=5.9-0.5 MPa-m0.5, density g=2.73 g/сm³. The materials obtained at 30 MPa, 2240-1950°C had much higher characteristics. γ-AlB₁₂ (94-98 wt.%, p=2.53-2.58 g/cm³) showed HV(49 N)=24.1 GPa; K_1<i>c</i> (49 N)=4.9 MPa-m0.5; bending R_bs=336 MPa and compressive R_cs=378 MPa strengths. Composite 74 wt.% AlB₁₂C₂, 22 wt% TiB₂ , 4 wt% Al₂O₃ (p=3.1 g/сm3) had HV(49N)=37.65-6.74 GPa, K_1<i>c</i>(49 N)=5.2 MPa-m0.5, R_bs = 646 MPa and R_cs =795 MPa. B4C(p=2.52 g/сm3) demonstrated HV(4.9 N)=40 GPa, K_1<i>c</i> (3-point bending)=4.89 MPa-m0,5, R_cs=392 MPa, R_cs=1551 MPa and B₄C-20%SiC (p = 2.67 g/cm³) had HV(49 N)= 35 GPa, K_1<i>c</i>(3-point bending)=5.9 MPa-m0,5, R_bs=474 MPa, R_cs=1878 MPa.

References:
[1] Kisly, P. S., Neronov, V.A., Prikhna, T. A., Bevza, Yu.B. (1990). Aluminum borides, Kiev, Naukova Dumka, 1-192. (in Russian) (Кислый П. С., Неронов В. А., Прихна Т. А., Бевза Ю. В. Бориды алюминия. К.: Наук. Думка, 1990. 192 с).
[2] Whittaker, M. L., (2012) Synthesis, characterization and energetic performance of metal boride compounds for insensitive energetic materials, Thesis for the degree of Master of Science : - The faculty of the University of Utah Department of Materials Science and Engineering, University of Utah.
[3] Domnich, V., Reynaud, S., Haber, R.A., Chowalla, MJ. Am. Ceram. Soc., 94 (2011) 3605-3628.
[4] Prikhna, Т. A., Barvitskiy P. P., Karpets М. В., Muratov V. B., Sverdun V. B., Haber R., Kartuzov V. V., Moshchil V. E., Dub S. N., Loshak M. G., Alexandrova L. I., Kovylaev V. V., Garbuz V.V., Marchenko A. A., J. Superhard Materials, 39(5) (2017) 299-307.
[5] Prikhna, Т.А., Haber, R. A., Barvitskiy, P. P., Sverdun,V. B., Dub, S. N., Muratov, V. B., Domnich , V., Karpets, М. V., Moshchil, V. E., Loshak, М. G., Kovylaev, V.V., Vasiliev O.O., Proceedings of the 41st International conference and exposition on advanced ceramics and composites, January 22 - 27, 2017, Daytona Beach, Fla., USA., http://acumen-va-publish.com/ACerS/ICACC_2017/toc.html.