| 2021 №03 (06) |
DOI of Article 10.37434/sem2021.03.07 |
2021 №03 (08) |
Electrometallurgy Today (Sovremennaya Elektrometallurgiya), 2021, #3, 42-48 pages
Influence of heat treatment on the structure and fracture mode of welded joints of sparsely-alloyed titanium alloy
S.G. Grigorenko, T.G. Taranova, V.A. Kostin, T.G. Solomijchuk, V.Yu. Bilous, E.L. Vrzhizhevskyi
E.O. Paton Electric Welding Institute of the NAS of Ukraine. 11 Kazymyr Malevych Str., Kyiv, 03150, Ukraine. E-mail: office@paton.kiev.ua
Abstract
Studied is the influence of preheating and further local heat treatment on the structure, fracture mode and properties of welded joints of sparsely-alloyed pseudo-β-titanium alloy of Ti–Al–Mo–Fe system. The structure of welded joints produced by electron beam welding and surfaces of fractures obtained after impact toughness testing of the samples were investigated. It is found that application of preheating and local heat treatment after electron beam welding allows avoiding formation of a metastable αʹ-phase in the welded joint and lowering the content of β-phase in the weld metal to 72 % that enables increasing the values of strength and ductility. Additional local heat treatment after welding with preheating leads to a more uniform arrangement of areas of brittle and ductile fracture on the fracture surface, and also promotes transformation of α-phase particles of different size and shape into a dispersion-strengthened structure that ensures a more favourable combination of strength, ductility and toughness. The strength of welded joint produced with preheating and local postweld heat treatment is on the level of 98 % of base metal strength. Ref. 12, Tabl. 1, Fig. 7.
Keywords: sparsely-alloyed titanium alloys; electron beam welding; ingot; structure; fracture mode; mechanical properties; local heat treatment
Received 14.06.2021
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