| Abstract Scope |
Additive manufacturing (AM) is rapidly expanding the utilization of high-strength aluminum alloys in engineering components across various industries. However, nanostructure control strategies to improve strength and ductility are still lacking. Here, we exploit a strategy using ceramic microparticles and the thermal cycles of laser powder-bed-fusion to achieve ultra-dense solute nanoclusters in aluminum alloys, which results in unprecedented tensile properties. Using TiB2 microparticles as an example, we minimize the differences in interfacial energies between various crystallographic combinations of aluminum and microparticles through computational design, which enables an equiaxed grain structure. Meanwhile, the thermal misfit between microparticles and matrix induces high-density dislocations. The back-and-forth motion of these dislocations, driven by internal cyclic stresses, spontaneously generates dense vacancies in the as-built alloy and facilitates the creation of metastable, ultra-dense solute clusters after direct ageing. Remarkable strengthening and strain hardening can then be achieved, exhibiting far superior tensile properties compared to additively manufactured counterparts. |