Introducing a novel fabrication route for metastable β-type Ti–Cr–Sn alloys with ultra-high Sn content using pure elemental mixed powders via laser powder bed fusion

This study investigates the fabrication of ultra-high Sn-containing metastable β-type Ti–Cr–Sn alloys using Laser Powder Bed Fusion ( L -PBF). By utilizing the rapid solidification inherent to L -PBF, retention of an ultra-high Sn metastable β phase at room temperature was achieved in compositions that are difficult to obtain via conventional processing routes. To address a key challenge in L -PBF, the high material cost associated with pre-alloyed powders, a mixture of pure elemental powders was employed as a cost-effective alternative feedstock. The effects of laser power on the microstructure, phase constitution, crystallographic texture, and mechanical properties of the as-built specimens were systematically evaluated. The results demonstrate that L -PBF successfully produced a homogeneous ultra-high Sn β solid solution while effectively suppressing the formation of ω phase and Ti 3 Sn compounds. Under the highest laser power condition of 360 W, complete melting and the formation of a single β phase were achieved. The conventional unidirectional laser scanning strategy (X-scan), in which the scanning direction is kept constant between layers, resulted in β alignment along the build direction and β alignment along the scan direction. The specimen fabricated at 360 W exhibited the most homogeneous microstructure, together with appropriate strength, excellent ductility, and low Young’s modulus. These findings demonstrate the feasibility of low-cost processing via L -PBF while achieving enhanced functional performance in high-Sn metastable β-Ti alloys.