Optimizing in-situ alloying in laser powder bed fusion: a study on Ti-W alloy feasibility and mechanical performances

The laser powder bed fusion (LPBF) technique is renowned for its ability to fabricate parts in a single step using a layer-by-layer laser-based production process. A key factor in optimizing LPBF lies in feedstock preparation, specifically through in-situ alloying, where elemental mixtures are adjusted to achieve tailored compositions. However, achieving uniform dispersion of fine elemental particles remains challenging due to inherent agglomeration, which can disrupt process efficiency and compromise alloy homogeneity—particularly when incorporating high-melting-point elements with slow diffusion rates. Additionally, the constraints of rapid solidification and limited molten pool dimensions further intensify these challenges, underscoring the need for strategic powder modification and precise mixing techniques. This study investigates the feasibility of fabricating titanium-tungsten (Ti-W) alloys via LPBF in a single-step manufacturing approach. Tungsten (Tm = 3422 °C), a refractory element with double the melting point of titanium (Tm = 1670 °C), was selected to examine alloy formation and its impact on mechanical properties. Various powder mixing strategies were evaluated to determine their effects on powder distribution, morphology, contamination levels, and mixing efficiency. Furthermore, the influence of input volumetric energy density (Ev) on alloy homogeneity, residual W particle distribution in Ti matrix, and microstructural evolution was analyzed. Key parameters such as density, phase fraction, and texture development were assessed to understand their role in optimizing mechanical performance. Our findings highlight that proper W integration through refined mixing strategies significantly enhances the strength of Ti while maintaining balanced ductility. This study provides valuable insights into advancing LPBF processing for refractory metal additions to Ti, paving the way for enhanced mechanical performance through in-situ alloying and multi-metal fabrication in additive manufacturing.