12 March 2019
Additive manufacturing of high-entropy alloys combines the mechanical properties of this
novel family of alloys with the geometrical freedom and complexity required by modern
designs. An approach to additive manufacturing of high-entropy alloys has been
developed based on 3D extrusion of inks containing a blend of oxide nanopowders (Co3
+ NiO), followed by co-reduction to metals, inter-diffusion and sintering to
near-full density CoCrFeNi in H2
. A complex phase evolution path is observed by in-situ X-ray
diffraction in extruded filaments: the oxide phases undergo reduction and the resulting
metals inter-diffuse, ultimately forming the desired fcc-CoCrFeNi alloy (see figure).
Linked to this phase evolution is a complex micro-structural one, from loosely packed oxide
particles to fully-annealed, metallic CoCrFeNi with 99.6 ± 0.1% relative
density. CoCrFeNi micro-lattices are created with strut diameters as low as 100 μm and
excellent mechanical properties at ambient and cryogenic temperatures.
6 March 2019
Abdominal aortic aneurysm, an enlargement of the abdominal aorta, may lead to rupture and thus acute health issues and death.
Scanning X-ray imaging enabled new insights in the nano-structure of calcifications associated with abdonimal and popliteal aneurysm and allowed mapping the distribution of nano- and micro-calcifications as well as of collagen, elastin and myofilament as building blocks of connective tissue across samples from human donors.