ORALS

SESSION: SISAMFriPM1-R3 E: Complexity in materials	Kobe International Symposium on Science of Innovative and Sustainable Alloys and Magnets (5th Intl. Symp. on Science of Intelligent and Sustainable Advanced Materials (SISAM))
Fri Oct, 25 2019 / Room: Dr. Christian Bernard
Session Chairs: Mariana Calin; Session Monitor: TBA

14:00: [SISAMFriPM105]
Designing Metallic Glasses and Heterophase Materials for Engineering Applications
Juergen Eckert¹ ; ¹Erich Schmid Institute of Materials Science, Leoben, Austria;
Paper Id: 70 [Abstract]

The structure of glasses is generally taken to be isoconfigurational, although it is well-known that the details of structure arrangement strongly depend on the temperature-time history experienced while establishing the glassy state. Recent studies of glass-forming metallic systems have revealed intriguing complexity, e.g. unusual shifts in radial distribution functions with temperature change or upon mechanical loading in the elastic or plastic regime. Nearest neighbour distances and medium-range order structural arrangements appear to change, e.g. shorten upon heating or become larger with decreasing temperature. Concomitantly, temperature changes as well as static or dynamic mechanical loading within the nominally elastic regime can trigger significant changes in glass properties, which are directly correlated with local non-reversible configurational changes due to non-affine elastic or anelastic displacements. All these findings strongly suggest that the characteristics of the atomic structure decisively determine the properties of the glass and of nanostructured materials derived from glass-forming systems. Recent findings and developments along this line will be summarized. Results from high-energy synchrotron x-ray radiation investigations at different temperatures and after mechanical loading will be related to the atomic structure of the material. It will also be related to its dependence on temperature, mechanical load as well as intrinsic heterogeneities and length-scale modulation to elucidate the correlation between atomic arrangement and mechanical or magnetic properties.

References:
1. Ashby, M.F., Greer, A.L.: Metallic glasses as structural materials. Scripta Materialia 54, 321 (2006).
2. Cubuk, E.D., et al: Structure-property relationships from universal signatures of plasticity in disordered solids. Science 358, 1033 (2017).
3. Scudino, S., Shakur Shahabi, H., Stoica, M., Kaban, I., Escher, B., Kühn, U., Vaughan, G.B.M., Eckert, J.: Structural features of plastic deformation in bulk metallic glasses. Applied Physics Letters 106, 031903 (2015).
4. Sarac, B., Zhang, L., Kosiba, K., Pauly, S., Stoica, M., Eckert, J.: Towards the better: Intrinsic property amelioration in bulk metallic glasses. Scientific Reports 6, 27271 (2016).
5. Bian, X.L., Wang, G., Yi, J., Jia, Y.D., Bednarcik, J., Zhai, Q.J., Kaban, I., Sarac, B., Mühlbacher, M., Spieckermann, F., Keckes, J., Eckert, J.: Atomic origin for rejuvenation of a Zr-based metallic glass at cryogenic temperature. Journal of Alloys and Compounds 718, 254 (2017).
6. Sarac, B., Ivanov, Y.P., Chuvilin, A., Schöberl, T., Stoica, M., Zhang, Z., Eckert, J.: Origin of large plasticity and multiscale effects in iron-based metallic glasses, Nature Communications 9, 1333 (2018).

SESSION: SISAMSatPM1-R3 H: Characterisation	Kobe International Symposium on Science of Innovative and Sustainable Alloys and Magnets (5th Intl. Symp. on Science of Intelligent and Sustainable Advanced Materials (SISAM))
Sat Oct, 26 2019 / Room: Dr. Christian Bernard
Session Chairs: A. Lindsay Greer; Session Monitor: TBA

14:50: [SISAMSatPM107]
Surface patterning by thermoplastic forming of Ni-free Ti-based bulk metallic glasses
Mariana Calin¹ ; Supriya Bera¹ ; Baran Sarac² ; Juergen Eckert² ; ¹IFW Dresden, Dresden, Germany; ²Erich Schmid Institute of Materials Science, Leoben, Austria;
Paper Id: 285 [Abstract]

Bulk metallic glasses (BMGs) exhibit a unique temperature-dependent mechanical behavior, which enables the processing of polymers at temperatures higher than the critical BMG-specific glass transition temperature [1]. In this work, we report on the thermoplastic behavior of two Ni-free Ti-based bulk metallic glasses by utilizing the dramatic softening of the amorphous structure in the supercooled liquid region. Ti₄₀Zr₁₀Cu₃₄Pd₁₄M₂ (M = Ga, Sn) bulk glassy alloys were produced by copper mold casting. Ga and Sn micro-alloying (2 at.%) improve the glass-forming ability and mechanical properties of Ti₄₀Zr₁₀Cu₃₆Pd₁₄ alloy effectively [2, 3]. The cast rods were thermo-mechanically characterized to determine the most suitable processing temperature, time, and the load that has to be applied for thermoplastic net-shaping of the BMGs into anisotropically etched cavities of silicon chips. Periodic features with high surface smoothness and uniform height were created on the surface of the BMGs. The surface patterning with controllable roughness of Ti-based BMGs can be useful in biomedical studies by mediating material - cell interactions. Financial support through the EC (FP7 VitriMetTech-ITN) and ERC-Advanced Grant "INTELHIB" is gratefully acknowledged.

References:
[1] J. Schroers, Acta Mater. 56 (3) (2008) 471-478.
[2] M. Calin, A. Gebert, A.C. Ghinea, P.F. Gostin, S. Abdi, C. Mickel, J. Eckert, Mat. Sci. Eng. C, 33 (2) (2013) 875-883.
[3] B. Sarac, S. Bera, S. Balakin, M. Stoica, M. Calin, J. Eckert, Mater. Sci. Eng. C, 73 (2017) 398-405.

SESSION: SISAMSatPM1-R3 H: Characterisation	Kobe International Symposium on Science of Innovative and Sustainable Alloys and Magnets (5th Intl. Symp. on Science of Intelligent and Sustainable Advanced Materials (SISAM))
Sat Oct, 26 2019 / Room: Dr. Christian Bernard
Session Chairs: A. Lindsay Greer; Session Monitor: TBA

15:15: [SISAMSatPM108]
Bulk metallic glasses studied by fast calorimetry combined with time resolved X-ray diffraction
Florian Spieckermann¹ ; Innozeznz Steffny² ; Xilei Bian² ; Sergey Ketov² ; Mihai Stoica³ ; Martin Rosenthal⁴ ; Juergen Eckert⁵ ; ¹University of Leoben, Leoben, Austria; ²Erich Schmid Institute, Austrian Academy of Sciences, Leoben, Austria; ³ETH Zuerich, Zuerich, Switzerland; ⁴ESRF, Grenoble, France; ⁵Erich Schmid Institute of Materials Science, Leoben, Austria;
Paper Id: 103 [Abstract]

Novel processing technologies for metals such as 3D printing require the application of high heating and cooling rates and ideally the use of isotropic materials. The glass-forming alloys are good candidates for such applications. We directly determine the thermodynamic fragility index of two metallic glasses (Mg₆₅Cu₂₅Gd₁₀ and Au₄₉Cu_26.9Si_16.3Ag_5.5Pd_2.3) from fictive temperature shifts induced by a variation of the quenching rate using fast differential scanning calorimetry (FDSC). Recent chip calorimeters are able to achieve the cooling rates necessary to perform such an evaluation. For the Mg₆₅Cu₂₅Gd₁₀ and Au₄₉Cu_26.9Si_16.3Ag_5.5Pd_2.3 metallic glasses studied, we find very good agreement of the kinetic fragility index with literature data obtained by conventional calorimetry and rheology. We also applied ultra-fast chip calorimetry in combination with time-resolved micro-diffraction directly recorded with fast pixel array detectors. This way we can investigate the structural modifications of bulk metallic glasses (BMGs), in-situ, on ultra-fast temperature changes. Combining the very high time resolution of structural and calorimetric data acquisition, we investigated the mechanisms and the kinetics of the metastable phase transformations of this group of materials at ultra-high rates of temperature change. The understanding of the kinetic transition paths of- to date still unknown- metastable material states is the foundation for the development of tailored thermomechanical treatment routes towards novel applications of BMGs.

References:
Spieckermann, F.; Steffny, I.; Bian, X.; Ketov, S.; Stoica, M. & Eckert, J.\nFast and direct determination of fragility in metallic glasses using chip calorimetry \nHeliyon, 5 , e01334