Asynchronous recrystallization in LPBF GH5188 alloy driven by asymmetric driving force and Zener pinning

The study addresses why LPBF alloys recrystallize non-uniformly using solid solution-strengthened GH5188. Melt pool geometry and remelting partition the build into core and peripheral grain populations, creating asymmetric driving forces and pinning. Calorimetry with derivative analysis resolves a staged pathway. EBSD shows recrystallization initiates in <100> core grains, while <101>/<111> peripheral grains lag. Higher stored energy in the core grains and stronger pinning in the periphery grains, together with orientation heterogeneity and high-angle boundaries, hinder front propagation. An RX-based metric is proposed to guide partial recrystallization for strength ductility synergy.