Designing printable alloys by tuning liquid short-range order

Metal additive manufacturing (AM) enables near-net shape synthesis in a single step with minimal waste, yet only a small fraction of commercial alloys are printable. This process-material incompatibility stems from AM’s high cooling rates, which favor grain growth over nucleation, leading to hot cracking, anisotropy, residual stresses, and poor damage tolerance. Alloy design efforts have aimed to enhance heterogeneous nucleation or epitaxial growth on precursor phases. Building on Franck’s pioneering 1952 hypothesis, recent studies show that topological short-range ordering (SRO) in undercooled liquids can drive crystal nucleation. This “icosahedral short-range order (ISRO)-mediated nucleation” mechanism, introduced by Kurtuldu & Rappaz, incorporates metastable liquid states and SRO as templates. In this Review, we discuss advances in understanding ISRO-mediated nucleation and discuss how quantum engineering of metallic liquids, i.e. manipulating electronic and atomic structures in the liquid state, stands out as a new alloy design paradigm to overcome current limitations in metal AM. This Review discusses how icosahedral short-range ordering can mediate crystal nucleation during additive manufacturing of metals, including manipulating electronic and atomic structure in the liquid state as an alloy design strategy.