Publication Highlights

In a recent Nature Communications publication, researchers at the Laboratory of Metal Physics and Technology unravel via multiple length-scale analysis the Invar effect, universally observed in magnetic Fe-based glasses. On the atomic scale it strongly affects the average Fe–Fe pair distance and can even cause thermal contraction of the Fe–Fe pairs.

A collaboration between researchers at the ETH Zurich Laboratory of Metal Physics and Technology and Empa has shown that Pd-based metallic glass demonstrates thrombogenic resistance that is substantially higher than that of state-of-the-art Ti64. With its superior mechanical properties, the Pd-based glass is particularly interesting for blood-contacting, load-bearing medical devices. The results are presented in Advanced Functional Materials.

In a recent ACS Nano publication, researchers at the Laboratory of Metal Physics and Technology have resolved the structure of a hierarchically phase-​separated metallic glass with a small volume fraction of (nano-​)crystalline inclusions. Applying X-​ray diffraction computed nanotomography (XRD-​nCT), they achieved submicron resolution by deploying a 500 nm focused monochromatic beam at the ESRF ID11 beamline.

A collaboration between researchers at EPF Lausanne and the ETH Zurich Laboratory of Metal Physics and Technology has shown that thermal drawing of metallic glasses in a polymer matrix generates conducting fibers with arbitrary transverse geometries, micro- and nanoscale feature sizes, and extreme aspect ratios. These fibers will have unique applications in flexible electronics and neuroscience. The results are presented in Nature Nanotechnology.

In a recent Advanced Science publication, Güven Kurtuldu and Jörg F. Löffler of the Laboratory of Metal Physics and Technology (LMPT) illustrate that metastable crystals can be isolated via ultrafast calorimetry. Investigating their thermophysical properties, they find that even a simple binary Au–Si eutectic alloy reveals four distinctly different melting points.

The phenomenon of age-hardening in metals was discovered at the beginning of the twentieth century. 110 years later, a research collaboration between the Montanuniversität Leoben and the ETH Zurich Laboratory of Metal Physics and Technology has revealed that this effect depends strongly on material dimensions. The results are presented in Nature Communications.

In a recent Advanced Materials publication, researchers at the Laboratory of Metal Physics and Technology (LMPT) present TEM experiments designed to follow the active nano-corrosion processes of biodegradable Mg alloys over periods ranging from seconds to days. They find that cathodically polarized dealloying of intermetallic nanoprecipitates governs their electrochemical reactivity. This presents a fundamentally new concept for active materials such as Mg alloys.

In a recent Adv. Mater. publication, researchers at the Laboratory of Metal Physics and Technology (LMPT) and Complex Materials have documented the creation of ordered porous Mg scaffolds via 3D NaCl printing (and sintering), Mg melt infiltration, and subsequent salt removal by leaching. These set the premise for a unique combination of tunable mechanical properties and the potential of being deployed as biodegradable implant, as the scaffold can be tuned to predictably biodegrade in the human body.

In a recent Nat. Comm. publication, Jörg F. Löffler from the Laboratory of Metal Physics and Technology (LMPT) and his colleague Jürgen Schawe from Mettler Toledo show that metallic glasses generally reveal multiple critical cooling rates that produce different types of monolithic glass, which the authors termed “self-doped glass” (SDG) and “chemically homogeneous glass” (CHG). The CHG reveals a tendency towards stochastic nucleation, which underlines the novelty of this glass state.

In a recent Phys. Rev. Lett. article, researchers at the Laboratory of Metal Physics and Technology (LMPT) have demonstrated that magnetization switching in ferromagnetic nanoparticles is linked to the dynamics of topological point defects, which form as Skyrmion lines and break via the creation of emergent magnetic monopoles. These move at speeds exceeding those of any other magnetic object known, and thus generate unprecedented solenoidal electric fields of several megavolts per meter.

In a recent PNAS publication, researchers at the Laboratory of Metal Physics and Technology (LMPT) have demonstrated that crystal nucleation from the melt may generally occur via an intermediate nucleation of metastable quasicrystals. This transition path was observed with a newly developed method of “up-quenching”, which can yield the discovery of hidden transient phases that are key to understanding the nucleation and crystallization behavior in metallic, polymeric and biological systems.

This Nat. Comm. article presents experimental evidence for a solid-solid phase transition via the formation of a metastable liquid in a metallic glass system. It provides further insight into phase transition theory and may also be of great importance for the understanding of new processing techniques where rapid cooling and heating are applied (e.g. 3D printing of metals).

Icosahedral short-range order (SRO) often dominates the structure and thus the properties of metallic glasses. This Phys. Rev. Lett. article now clarifies via MD simulations how such icosahedral SRO influences glass formation and mechanical properties.

This Adv. Funct. Mater. article summarizes our research over the last decade involving in-situ analysis of shear-band dynamics during straining experiments. It discusses the various stages of shear banding together with the extended time and length scales involved, also in the more general context of disordered materials.

This Phys. Rev. Lett. article describes how precipitation aging can be controlled in AlMgSi alloys via a part-per-million addition of Sn solutes, and explains via thermodynamic modeling and DFT calculations that this control of aging is due to vacancy diffusion which can be tuned by the Sn solutes. This “diffusion on demand” principle has great scientific and technological ramifications.

This Phys. Rev. Lett. article shows via in-situ acoustic emission monitoring that shear-band initiation results from a softening mechanism by local structural dilatation with volume changes of a few percent only. Because these are typical values of excess free volume in the undercooled liquid region near T_g, the onset of plasticity is attributed to a “stress-induced glass transition”.

This Phys. Rev. Lett. article describes the low-temperature freezing dynamics of the hemo-ilmenite mixed-spin oxide system. Above the Fe(III) percolation threshold unusual magnetic jumps occur at low temperatures (< 3 K), which is explained by a layerwise partitioning resulting from strong exchange and superexchange interactions that generate a collective rotation of the magnetic moments within this quasistochastic system.