Mechanical behaviour of additively manufactured metals

Additive manufacturing is reshaping the production of engineering components in diverse industries, such as the automotive, aerospace, defence and biomedical sectors, by offering outstanding design and fabrication flexibility. The non-equilibrium processing conditions inherent to additive manufacturing yield materials with unique microstructures and tailored mechanical properties that are often unattainable through conventional routes. This Review highlights recent advances in additively manufactured metals that show distinctive mechanical behaviours, including strength-ductility synergy, microstresses and gradient plasticity, fracture and fatigue resistance, and high-temperature creep performance. We examine the deformation mechanisms and micromechanical effects arising from the heterogeneous microstructures produced by additive manufacturing to guide the design of high-performance structural materials. Furthermore, we discuss critical research needs and emerging opportunities in processing control, alloy design, advanced characterization, computational modelling and machine learning aimed at achieving exceptional mechanical properties in additively manufactured metals.