Recent advances in hierarchical heterostructures and mechanical properties of additively manufactured aluminum alloys

Driven by the rapid advancement of key engineering domains such as aerospace, transportation and marine systems, there is an urgent need for aluminum alloys exhibiting superior mechanical properties. Heterostructures, defined by inhomogeneous distributions of microstructural domains with distinct property gradients, have become a leading strategy to achieve a synergy between outstanding strength and satisfactory ductility. Additive manufacturing (AM) technologies, particularly laser powder bed fusion (L-PBF), provide unparalleled design flexibility for creating heterogeneous microstructures. This review systematically classifies the various heterostructures in additively manufactured aluminum alloys, investigates the mechanisms enabling precise control of microstructural heterogeneity, and underscores the exceptional mechanical performance of L-PBF-processed alloys with such structures. Moreover, the challenges and opportunities associated with advancing heterostructured aluminum alloys via L-PBF are critically analyzed, highlighting the necessity for robust theoretical frameworks and scalable manufacturing approaches.