Harnessing additive manufacturing to architect hierarchical (TiB + Y 2 O 3 ) nanodispersions for exceptional strengthening of near-α titanium alloy

Laser powder bed fusion (LPBF) enables trace microalloying to form hierarchical (TiB + Y2O3) nanodispersions in near-α TA15 alloy: a quasi-continuous TiB network along primary-β grain boundaries plus intragranular Y2O3 nanoparticles. Despite totalling only 0.35 vol% reinforcements, this LPBF-architected structure achieves >10% strength gain at room temperature and, notably, 15% gain at 500°C while retaining comparable ductility — surpassing conventional composites that need an order-of-magnitude more reinforcements. This enhanced performance originates from synergistic strengthening mechanisms enabled by the thermally stable hierarchical nanodispersions. Therefore, precursor-assisted LPBF microalloying provides a useful strategy for designing high-strength near-α titanium alloys with minimal nominal reinforcement addition after process-window optimisation.