Publications by Güven Kurtuldu

Additive manufacturing of a precious bulk metallic glass

Jamasp Jhabvala, Güven Kurtuldu, Antonia Neels, Roland Logé, Navid Sohrabi, Annapaola Parrilli

For the first time, a high-density amorphous and crack-free bulk metallic glass (BMG) based on a precious metal (PdCuNiP) was produced via additive manufacturing (AM). Laser powder-bed fusion (LPBF) was used for the fabrication of the samples, and led to a ...

2021

Structured nanoscale metallic glass fibres with extreme aspect ratios

Giuseppe Schiavone, Güven Kurtuldu, Inès Richard, Stéphanie Lacour, Grégoire Courtine, Dang Tùng Nguyen, Fabien Sorin, Wei Yan, Yunpeng Qu, Vasiliki Tileli, Nicholas David James, Jordan Squair, Reinis Ignatans

Micro- and nanoscale metallic glasses offer exciting opportunities for both fundamental research and applications in healthcare, micro-engineering, optics and electronics. The scientific and technological challenges associated with the fabrication and util ...

Nature Publishing Group2020

Characterization, mechanical properties and dimensional accuracy of a Zr-based bulk metallic glass manufactured via laser powder-bed fusion

Jamasp Jhabvala, Güven Kurtuldu, Steven Van Petegem, Antonia Neels, Roland Logé, Efthymios Polatidis, Navid Sohrabi, Annapaola Parrilli

Bulk metallic glasses (BMGs) are high-strength, highly elastic materials due to their disordered atomic structure. Because BMGs require sufficiently high cooling rates to bypass crystallization, laser-based additive manufacturing (AM) methods have recently ...

2020

Solidification of Metallic Alloys: Does the Structure of the Liquid Matter?

Michel Rappaz, Güven Kurtuldu

In 1952, Frank (Proc R Soc Lond Ser-Math Phys Sci 215:43-46, 1952) already postulated that Icosahedral Short Range Order (ISRO) of atoms in the liquid could possibly explain the large nucleation undercoolings measured in metallic alloys by Turnbull and Fis ...

SPRINGER2020

Influence of Minor Cr-Additions to the Growth of Columnar Dendrites in Al-Zn Alloys: Influence of Icosahedral Short Range Order in the Liquid

Michel Rappaz, Güven Kurtuldu

The effect of minute Cr additions on dendritic growth directions in Al-20 wt pct Zn alloy has been investigated. As first evidenced by Gonzales and Rappaz (Metall Mater Trans A 37:2797-2806, 2006) Al-Zn alloys exhibit a Dendrite Orientation Transition (DOT ...

SPRINGER2020

Comment on "Formation of twin boundaries in commercial purity aluminum with addition of Ti refiner" by Zhongwei Chen, Jianping Gao, Kang Yan

Michel Rappaz, Güven Kurtuldu

ELSEVIER SCIENCE BV2019

Quasicrystal-Enhanced Nucleation During the Solidification of fcc Metallic Alloys: A Tentative Thermodynamic Approach

Michel Rappaz, Güven Kurtuldu

short communication ...

Springer2016

Influence of icosahedral short range order on diffusion in liquids: A study on Al-Zn-Cr alloys

Michel Rappaz, Güven Kurtuldu

It has been shown recently that minute additions of Cr in Al-Zn alloys refine the solidified grain structure and induce multiply-twinned grains which can only be explained if the icosahedral symmetry is considered (Kurtuldu et al., 2013). It has been sugge ...

Elsevier2016

Thermodynamic Aspects of Homogeneous Nucleation Enhanced by Icosahedral Short Range Order in Liquid Fcc-Type Alloys

Michel Rappaz, Güven Kurtuldu

We have recently shown that minute solute element additions to liquid metallic alloys can strongly influence the nucleation of the fcc phase and act as a grain refinement method. Electron back-scattered diffraction observations revealed a concomitant incre ...

Springer2015

Probability of twin boundary formation associated with the nucleation of equiaxed grains on icosahedral quasicrystal templates

Michel Rappaz, Güven Kurtuldu

Recently, we have shown that minute Cr additions (typically 0.1 wt%) to Al-Zn alloys solidified in a uniform temperature field lead to the formation of fine equiaxed fcc Al grains [1]. Furthermore, these grains exhibit an unexpectedly large number of twin, ...

Iop Publishing Ltd2015

Peritectic reaction on the Al-rich side of Al-Cr system

Michel Rappaz, Güven Kurtuldu

A long lasting controversy on the nature of the reaction between liquid, Al and Al45Cr7 has been ended by planar front solidification experiments of Al-Cr alloy in a Bridgman furnace. Cr depletion in the liquid ahead of the quenched planar interface proves ...

Elsevier2015

Measurement of Mechanical Coherency Temperature and Solid Volume Fraction in Al-Zn Alloys Using In Situ X-ray Diffraction During Casting

Jean-Marie Drezet, Güven Kurtuldu, Bastien Gilbert Pierre Mireux

During solidification of metallic alloys, coalescence leads to the formation of solid bridges between grains or grain clusters when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behavior ...

Springer Verlag2015

In situ X-ray Diffraction during Casting: Study of Hot Tearing in Al-Zn alloys

Jean-Marie Drezet, Güven Kurtuldu, Bastien Gilbert Pierre Mireux

During solidification of metallic alloys, coalescence corresponds to the formation of solid bridges between grains when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behaviour of solidif ...

Trans Tech Publications Switzerland2015

Icosahedral quasicrystal-enhanced nucleation of the fcc phase in liquid gold alloys

Michel Rappaz, Güven Kurtuldu, Alberto Sicco

Although the grain refinement of yellow gold alloys with Jr has been used in industry and known for nearly half a century, the basic mechanism is still unknown. The present contribution shows that the mechanism is the same as that evidenced recently in Al- ...

Elsevier2014

Influence of Trace Elements on the Nucleation and Solidification Morphologies of Fcc Alloys and Relationship with Icosahedral Quasicrystal Formation

Güven Kurtuldu

EPFL2014

Influence of Cr on the nucleation of primary Al and formation of twinned dendrites in Al-Zn-Cr alloys: Can icosahedral solid clusters play a role?

Michel Rappaz, Güven Kurtuldu

The equiaxed solidification of Al-20 wt.% Zn alloys revealed an unexpectedly large number of fine grains which are in a twin, or near-twin, relationship with their nearest neighbors when minute amounts of Cr (1000 ppm) are added to the melt. Several occurr ...

Elsevier2013