Abstract

Metastable β-titanium alloys are attractive for the aerospace industry and medical applications, due to their low density, high strength, low young modulus, and excellent hardenability. Among these alloys, Titanium Grade 21S is renowned for its outstanding elevated temperature strength, creep resistance, corrosion resistance and mechanical properties. However, its limited weldability and poor thermal conductivity present significant challenges to traditional manufacturing methods, resulting in increased difficulty and costs. This study explores the potential of laser powder directed energy deposition (LP-DED) to fabricate Ti-21S samples. This additive manufacturing (AM) technique as compared to other fusion-based AM processes, offers faster material deposition rates, resulting in faster build times. The produced components were comprehensively evaluated for their microstructure, mechanical properties, and corrosion behavior using various methodologies. Based on the defect analysis, it was achieving >99.9% of theoretical density with appropriate processing parameters. Microstructure analysis indicated a fully beta-phase microstructure alongside notable mechanical strength and corrosion resistance. Hardness and microstructural uniformity were consistent across all samples, while electrochemical tests demonstrated robust resistance to aggressive environments. These findings underscore the effectiveness of LP-DED as a processing technique for Ti-21S, preserving its advantageous properties and addressing the limitations of conventional manufacturing.

Keyword: Beta-Ti21S alloy; Laser powder directed energy deposition; Additive manufacturing; electrochemical; Ti alloys.