Contact

Yasmin Ahmed Salem, M.A.
Yasmin Ahmed Salem
Press and Public Relations Officer
Phone: +49 211 6792 722
Room: 222

Scientific Events

Scientific Events

Month:

3418 1456997668

Nanostructure of wet-chemically prepared, polymer-stabilized silver–gold nanoalloys (6 nm) over the entire composition range

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3419 1456997693

Design and characterization of novel TiAl alloys and metal-diamond composites for beam-based additive manufacturing

Metal additive manufacturing (AM) techniques are powder-based, layer by layer methods which can directly build 3D structures onto substrates with complex geometries. They offer a unique ability to dynamically mix materials during the deposition process and produce functionally graded structures, new composite microstructures and perhaps even new material classes. Some of the challenging issues related to the energy beam based process are the very high heating and cooling rates, leading to non-equilibrium microstructures, which are usually harder, less ductile, and often exhibit high residual stresses; the strongly textured, anisotropic microstructures inherited from the solidification conditions; or the pronounced residual stresses resulting from the large thermal gradients in the AM fabricated parts. However, the very rapid consolidation of the material in a small material volume and the achieved high solidification rates allow for the manufacture of components containing meta-stable materials. In this talk some relevant results of the AM related research at Empa will be presented. The first part of the presentation deals with the development and characterization of a novel oxide dispersion strengthened (ODS) titanium aluminide alloy (Ti-45Al-3Nb ODS) for beam-based AM processes. The alloy design and selection process was supported by computational thermodynamics based on the CALPHAD approach, taking into account requirements for processing as well as long term alloy behavior under service conditions. Besides, an in situ method to study the behavior of alloys during rapid heating and cooling combining laser heating with synchrotron micro X-ray diffraction (microXRD) and high-speed imaging was developed. In the second part, the feasibility of producing metal-diamond composites by SLM was studied. A Cu-Sn-Ti alloy powder was mixed with 10-20 vol.% artificial, mono-crystalline diamonds. The influence of the processing parameters on the density and microstructure of the composites as well as on the stability of the diamonds was studied. It was shown that stable specimens containing intact diamonds could be produced. [more]

Properties of CuCdTeO films: from solid solutions to composites

3421 1456997715

Properties of CuCdTeO films: from solid solutions to composites

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Career Talk

Tailoring Metastable Metallic Materials for Engineering Applications

2559 1518608093

Tailoring Metastable Metallic Materials for Engineering Applications

In modern society, metallic materials are crucially important (e.g. for applications related to energy, safety, infrastructure, transportation, health, medicine, life sciences, IT). Contemporary examples with inherent challenges to be overcome are the design of ultrahigh specific strength materials. There is a critical need for successful developments in this area in particular for reduced energy consumption, reduction of pollutant emissions and passenger safety. Also, the ageing society makes biomedical materials for implant and stent design crucially important. A drawback of nearly all current high strength metallic materials is that they lack ductility (i.e. are brittle and hard to form) - or on the opposite side, they may be highly ductile but lack strength. Hence, it is mandatory to develop new routes for creation of tailored metallic materials based on hierarchical hybrid structures enabling property as well as function optimization. One starting point along these lines is the design of monolithic amorphous materials or bulk micro-, ultrafine- or nano-structured composite structures with intrinsic length-scale modulation and phase transformation under highly non-equilibrium conditions. This can include the incorporation of dispersed phases which are close to or beyond their thermodynamic and mechanical stability limit thus forming hierarchically structured hybrid and ductile/tough alloys. Alternatively, the material itself can be designed in a manner such that it is at the verge of its thermodynamic/mechanical stability. This talk will present recent results obtained for metallic glass-based hybrid structures with transformation effects at different length-scales and microcrystalline-grained hybrid structures based on elastic instabilities and modulated length-scale. The deformation behaviour and possible phase transitions during deformation will be related to the intrinsic properties of the phases as well as the microstructure of the material including heterogeneities and length-scale modulation in order to derive guidelines for the design of macroscopically ductile high-strength materials. Finally, the results will be critically assessed from the viewpoint of possible scaling-up for technological applications and the use of simple and cost effective processing technologies. [more]

New insights into interfaces of metals, oxides and nanoparticles via APT

2542 1456997757

New insights into interfaces of metals, oxides and nanoparticles via APT

In many materials, internal interfaces and surfaces are governing their properties. Due to the inherently atomic scale of interfaces, they have notoriously been elusive to structural and chemical analysis, limiting our current understanding about their behavior. Atom probe tomography, as a single atom sensitive mass spectrometry method with atomic resolution achievable, can significantly add to the understanding of interfaces. In this talk, I will present results on the analysis of local chemistry at grain boundaries in metals and oxides and the challenges associated with the data interpretation. This will also include nanomaterials such as nanoparticles and nanowires, where surface distributions of the chemical elements can be investigated and correlated with the particle’s properties. [more]

Technology Transfer

2506 1442218967

Technology Transfer

• advises and supports scientists at Max Planck Institutes in evaluating their inventions and filing patents • mediates the transfer of inventions from Max Planck Institutes to industry • supports scientists at Max Planck Institutes in founding companies [more]

 
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