Advancements in understanding the microstructure and properties of additive manufacturing Ti-6Al-4V alloy: A comprehensive review

In recent years, considerable attention has been devoted to implementing additive manufacturing (AM) techniques in the fabrication of Ti-6Al-4V alloy. During manufacturing, metallic powders are melted and rapidly solidified utilizing laser or electron beam sources, experiencing intricate thermal cycles that confer unique microstructural characteristics and exceptional performance attributes upon the titanium alloys. This paper presents an exhaustive review of the utilization of AM technologies in the production of Ti-6Al-4V alloy, with particular emphasis placed on this alloy itself. Specifically, the advantages and limitations of two prominent AM methodologies-laser powder bed fusion (LPBF) and directed energy deposition (DED)-are critically evaluated. Moreover, an in-depth analysis of pore defect formation mechanisms is provided, elucidating their consequential influence on the mechanical integrity of AM-processed Ti-6Al-4V alloy. Additionally, this review summarizes and contrasts the mechanical properties, hardness, wear resistance, corrosion resistance, and oxidation resistance exhibited by Ti-6Al-4V alloy fabricated through various AM technologies, as well as methodologies implemented to enhance these characteristics. In aggregate, this review aims to provide a robust theoretical framework and pivotal insights essential for advancing the development of high-performance titanium alloys through the strategic deployment of AM technologies. Additive manufacturing (AM) processes, such as DED and LPBF, involve melting metal powders with lasers or electron beams to produce unique microstructures and outstanding performance. This review summarizes the advantages and disadvantages, microstructure, pore defect formation mechanism, and their impact on performance of these 3 AM methods. At the same time, the mechanical properties, hardness, wear, corrosion, and oxidation resistance of Ti-6Al-4V alloy produced by AM are summarized, providing insights for the future development of high-performance titanium alloy manufacturing.