A novel additive manufacturing approach will be investigated where inks containing mixed (Co,Cr,Fe,Ni) oxide and (Hf,Nb,Ta,Ti,Zr) hydride particles are extrusion-3D printed into filaments and micro-lattices, which are then reduced to metals, inter-diffused to form high entropy alloys (HEA), and sintered to achieve dense material. A systematic study will be carried out that explores the mechanisms and kinetics of co-reduction or co-decomposition, inter-diffusion and porosity evolution as a function of particle composition, size and packing fraction, reducing species (H2 or C) and presence of space-holders and/or foaming agents to achieve designed intra-filament porosity, throughout the ink synthesis, 3D printing, and subsequent heat treatment. Fibers, struts and micro-trusses will be 3D-printed and subsequently homogenized and sintered while observing the evolution of the pores and intermediate and final phases, using both ex situ metallographic techniques and in situ X-ray diffraction and tomography. Diffusion-based models will be developed and compared to experiments, to describe and predict the sintering and inter-diffusion behaviour during the process. Finite element models will be created to optimize mechanical properties of the micro-lattices, based on strut porosity, phases and geometry.
|Effective start/end date||8/1/20 → 7/31/23|
- National Science Foundation (DMR 2004769)