Molecular dynamics model links titanium nanopowder coating to lower melting point

A molecular dynamics simulation of five stacked layers of titanium nanopowder found that a succinic acid coating lowered the powder’s melting point. The model also showed a sequential process in which particles nearest a constant-temperature substrate melted first, liquid titanium diffused upward through spaces between particles, and an ordered hexagonal close-packed structure developed from the substrate during solidification. These results provide a nanoscale computational view of interfacial premelting, pore closure and recrystallization in a powder bed fusion setting.

For the simulation, the researchers used a substrate maintained at 1,500 K as the sole heat source. They analyzed temperature distribution, energy evolution, mean square displacement and crystal structure to follow the behavior of surface-modified nano-titanium powder under a vertical thermal gradient. The work is a modeling study rather than an experimental demonstration, and its findings concern simulated atomic-scale behavior rather than the performance of an additively manufactured titanium component.

The simulations indicated that particles contacting the heated substrate first developed liquid regions at their surfaces. Heat and atoms then moved upward through the liquid phase, filling interparticle pores and warming particles in successive layers above. Atomic activation at the bottom of the stack was followed by the formation of an ordered hexagonal close-packed structure.

As solidification proceeded, this crystalline structure propagated upward. Together, these modeled effects suggest a mechanism by which smaller particles and surface modification could alleviate some processing difficulties associated with thermal gradients and interlayer defects in titanium alloy powder bed fusion. Titanium alloy powder bed fusion generally uses high-energy beams to melt and solidify successive layers of powder, but the process is challenged by powder oxidation, steep thermal gradients, residual stress and interlayer defects.

The constant-temperature substrate setup deliberately isolates heat transfer from a heated build surface. It therefore differs from the full beam-based process and does not establish how the simulated nanoscale behavior translates into component quality, defect rates or mechanical performance during actual manufacturing. The result involving succinic acid addresses a specific limitation within the model: the coating lowered the melting point of titanium nanopowder.

The authors interpret this as evidence that succinic acid-modified titanium nanopowder may help reduce constraints associated with the material’s processing window. The finding is limited to the simulated conditions, however.

Subject of Research: Molecular dynamics simulation of thermal melting and recrystallization in surface-modified titanium nanopowder for powder bed fusion

Article Title: Molecular dynamics simulation on additive manufacturing of surface-modified nano-titanium powders under constant substrate heating

Article References: Hu, H., Li, A., Guo, T., Liu, R., & Liu, Y. (2026). Molecular dynamics simulation on additive manufacturing of surface-modified nano-titanium powders under constant substrate heating. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13962-8

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13962-8

Keywords: titanium nanopowder, molecular dynamics, powder bed fusion, additive manufacturing, succinic acid, surface modification, melting behavior, atomic diffusion, pore closure, recrystallization, Molecular, dynamics