Enhanced strength and ductility of oscillating laser additive manufactured aluminum alloys with micron-sized Ti3AlC2 MAX-phase

Abstract

Excellent balance of strength and ductility was achieved in oscillating laser additive manufactured aluminum alloys by adding the micron-sized Ti3AlC2 phase, avoiding the aggregation of conventional nano-ceramic phases at grain boundaries. The printed 2024Al alloys samples exhibit a fully equiaxed and refined grain structure, attributed to the solid-phase transformation of the Ti3AlC2 phase, and its in-situ release of Ti atoms to form the Al3Ti phase, providing heterogeneous nucleation for grain refinement. Also, the introduced Ti3AlC2 particles transformed into the Al3Ti phase and the precipitated clusters of TiC and Ti3AlC, where TiC concentrated in the outer region forms a low-mismatch semi-coherent interface with the aluminum matrix. Finally, the printed samples had a yield strength of 255 MPa, a tensile strength of 423 MPa, and an elongation to failure of 13.2%.