Work

Defect suppression via nano-Mo substitution during laser powder bed fusion of Mo alloys

Year: 2026

Type: article

Abstract: Eliminating insufficient melting while avoiding keyhole defects is a critical challenge in the fabrication of refractory Mo-based alloys using laser powder bed fusion (L-PBF). Previous studies have primarily focused on ceramic nanoparticle reinforcement to improve the printability of Mo-based alloys. However, these strategies can introduce interfacial incompatibility and compositional heterogeneity. In this paper, a partial metallic nanoparticle substitution strategy is proposed to enhance the powder properties and L-PBF processability of challenging elemental MoTi mixed-powder systems. Single-track experiments and simulations revealed that the introduction of Mo nanoparticles enhanced the laser–powder interaction and thermal conductivity, leading to complete melting. Consequently, a fully dense MoTi alloy free from lack-of-fusion defects was successfully fabricated using L-PBF. This unique alloy exhibited a refined microstructure characterized by uniformly dispersed nanoscale TiO precipitates rather than the commonly formed Mo oxides, leading to reduced crack density. These findings demonstrate that the partial nanoparticle substitution strategy not only addresses the insufficient melting problem of refractory materials but also provides a promising pathway for the in situ removal of brittle boundary oxides, thereby contributing to crack suppression in the additive manufacturing of Mo-based alloys.

Source: Materials & Design

DOI: 10.1016/j.matdes.2026.115824