Abstract
The successful replacement of the present generation of corrosion-resistant materials (nitric acid-grade stainless steel and Ti) by Ti-5Ta-1.8Nb, which has better corrosion resistance, depends on its weldability characteristics. This article presents the results of a study on the fabrication, qualification, and microstructural characterization of the welds. Welding was carried out using the direct current electrode negative (DCEN) polarity tungsten inert gas (TIG) (manual) welding method with high-purity Ar shielding. Testing was carried out as per the ASME standard (section IX, welding and brazing). Qualification tests found that the weldment met the required properties. The weldment showed heterogeneous microstructures, which are rationalized based on differences in phase transformation mechanisms that are dictated by the thermal cycles experienced by various microscopic regions. The results, described in this article, confirm that the weldability of the developmental Ti-Ta-Nb alloy is excellent. A preliminary evaluation of the corrosion behavior of the welds showed rates comparable to that of the base metal, establishing that this alloy could be considered as an alternative material for use in highly corrosive environments.
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Karthikeyan, T., Dasgupta, A., Saroja, S. et al. Weldability and microstructural variations in weldments of Ti-5Ta-1.8Nb alloy. J. of Materi Eng and Perform 14, 241–248 (2005). https://doi.org/10.1361/10599490523391
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DOI: https://doi.org/10.1361/10599490523391