In WP1, FSP can be used to improve the ductility of high strength aluminum alloys by a factor 2.5 without loss of strength when performing a post-FSP treatment. Such an improvement cannot be reached by heat treatments alone. The improvement is expectedly associated to the grain size reduction due to FSP and the suppressing of large Mg-Zn precipitates at the grain boundary. This significantly changes the damage mechanism. FSP also improves the ductility of SLM aluminum alloys by a factor 4 and the fatigue life by a factor 100 due respectively to the Si network breakdown and porosity reduction delaying fatigue crack nucleation (Figure 2). This work was even proven to be extendable to titanium alloys.
In WP2, FSP can also be used to produce a material with local residual stress by inserting NiTi particles inside an aluminum matrix and trigger shape memory effect (Figure 3 and 4). In the first two years of the project a proof-of-concept material (with Al1050 as matrix material) has been manufactured showing local residual stresses around NiTi particles (Figure 5). Now work is under way to extend the concept to high strength (7xxx series) aluminum alloys (WP4).
In WP3, FSP and additive manufacturing were also used to manufacture healable aluminum alloys. Healing was achieved in Mg supersaturated Al alloy. The healing mechanism was evaluated using in-situ heating in high resolution (35 nm) synchrotron nanoholotomography (Figure 6, performed at ESRF Grenoble) and in transmission electron microscopy (collaboration with University of Antwerp). As the process requires 16 passes of FSP, additive manufacturing is now envisioned as a new manufacturing route for these new composites.
