Tensile Behavior and Evolution of the Phases in the AlCoCrFeNiTi Compositionally Complex/High Entropy Alloy.

Compositionally complex alloys, or high entropy alloys, are good candidates for applications at higher temperatures in gas turbines. After their introduction, the equiatomic AlCoCrCuFeNi (at.%) served as a starting material and a long optimization road finally led to the recently optimized AlCoCrFeNiTi (at.

Influence of W, Mo and Ti trace elements on the phase separation in Al8Co17Cr17Cu8Fe17Ni33 based high entropy alloy.

Compositionally complex alloys, also called high entropy alloys, have been investigated for over a decade in view of different applications, but so far only a small number of alloys can be considered as presenting good enough properties for industrial application. The most common family of elements is Al-Co-Cr-Cu-Fe-Ni. The equiatomic alloy having 5 phases and being too brittle, the composition has been modified in order to improve the mechanical properties.

Mapping the evolution of hierarchical microstructures in a Ni-based superalloy.

Phase separation of γ' precipitates determines the microstructure and mechanical properties of nickel-based superalloys. In the course of ageing, disordered γ spheres form inside ordered (L12) γ' precipitates, undergo a morphological change to plates and finally split the γ' precipitates. The presence of γ particles inside γ' affects coarsening kinetics and increases alloy hardness.

Catalytic activity of nanoalloys from gold and palladium.

We present a quantitative study of the catalytic activity of well-defined faceted gold-palladium nanoalloys which are immobilized on cationic spherical polyelectrolyte brushes. The spherical polyelectrolyte brush particles used as carriers for the nanoalloys consist of a solid polystyrene core onto which cationic polyelectrolyte chains of 2-aminoethyl methacrylate are attached. Au/Pd nanoalloy particles with sizes in the range from 1 to 3 nm have been generated which are homogeneously distributed on the surface of the spherical polyelectrolyte brushes.

Sonochemical formation of metal sponges.

A novel sonochemical method for formation of mesoporous metal sponges is developed. Systematic investigation of ultrasound effects on various types of metal particles reveals the cavitation-induced oxidation of metal surface and etching of metal matrix as main factors in the ultrasound-driven metal modification. Beyond the specific examples, the findings provide guidelines for expansion of the concept towards a broad variety of metal systems and allow development of the sonochemical approaches to manipulation of the metal surface and inner structure.