Overview of the microstructures of the tested variants of the alloy Ti-6Al-4V and comparison of their mechanical properties.
Source: BAM, division Experimental and Model Based Mechanical Behaviour of Materials
Additive manufacturing (AM) technologies offer the potential for time-saving production chains and fast availability of prototypes, which is of high relevance due to today’s demand for quick market launch. One of the several existing AM technologies is laser powder-based directed energy deposition (DED L); a powder nozzle-based process also known as laser metal deposition. In this AM process, a weld track is formed using metal powder as filler material, which is fed through a nozzle to a melt pool created by a focused high power-density laser beam. Several deposited weld tracks form together the desired three dimensional geometry. Powder nozzle-based processes enable additive manufacturing with high build-up rates and multi-layer build-ups that enable the modification or repair of existing components. To achieve this DED L must consider specific challenges. It must achieve uniform volume growth over hundreds of layers and avoid heat buildup of the deposited material. This work presents the characterization of the titanium alloy Ti 6Al 4V fabricated by DED L. This alloy is of interest since it is widely used in industrial and medical applications due to its excellent mechanical properties, low density, outstanding corrosion resistance, and biocompatibility. The characterization proves the reproducibility of properties between individual blanks and with respect to the building height. Besides, it demonstrates that excellent mechanical properties are achieved at room temperature and 400 °C. Furthermore, the article highlights and demonstrates the importance of the combined use of shielding and carrier gas flow to form the local protective gas atmosphere. The properties determined are evaluated by comparing them to the properties of two additionally tested variants of the same alloy produced using more established manufacturing processes. The knowledge generated from this and other planned characterization activities on this material could be useful for the AM community to develop approaches to extend the achievable properties and range of applications of this AM alloy.
Characterization of Ti-6Al-4V fabricated by multilayer laser powder-based directed energy deposition
Luis Alexander Ávila Calderón, B. Graf, Birgit Rehmer, T. Petrat, Birgit Skrotzki, Michael Rethmeier
published in Advanced Engineering Materials, page1-15, 2022
BAM department Materials Engineering division Experimental and Model Based Mechanical Behaviour of Materials