Microstructure and mechanical properties of laser printed Ti–25V–15Cr burn-resistant alloy using elemental powders including ball-milled Ti

This study investigates the effects of low-cost ball-milled modified titanium powder (BM Ti) on the laser powder bed fusion (LPBF) fabrication of Ti–25V–15Cr burn-resistant titanium alloy. Through systematic analyses of the powder characteristics, printing quality, microstructural evolution, and mechanical properties of BM Ti, it was found that the ball-milled modification improved the particle size distribution uniformity and flowability of the powder while reducing costs by approximately 65.8 %. The alloy specimens printed with BM Ti achieved a relative density of 99.57 %, albeit with higher oxygen content. Microstructural analysis revealed that the high dislocation density and nanocrystalline structure of BM Ti were transmitted to the alloy matrix, leading to coarser β-Ti grains and promoting the precipitation of ω/O′ nanoprecipitates. Although the hardness remained largely unchanged due to enhanced interstitial solid solution strengthening compensating for reduced grain refinement, the tensile plasticity of BM-Ti-25V–15Cr significantly deteriorated. This was attributed to the combined effects of oxygen-induced embrittlement and void defects (up to tens of micrometers in diameter) and unmelted V/Cr particles (6.34 % unmelted rate in horizontal sections). Post-heat treatment at 540 °C partially restored plasticity. However, the high-temperature creep performance of BM-Ti-25V–15Cr remained inferior. Despite its cost advantages, this study demonstrates that BM Ti requires further optimization of powder preparation and printing parameters to balance performance and affordability. The findings provide theoretical and technical insights for the application of low-cost titanium powders in additive manufacturing of burn-resistant titanium alloys.