Structure and Technological Aspects of Obtaining Qualitative Semi-Finished Products from Heat-Resistant Intermetallic Ti$_{2}$AlNb-Based Alloy with Improved Properties Complex

S. V. Skvortsova$^{1}$, A. A. Ilyin$^{1}$, M. G. Shtutsa$^{2}$, A. V. Aleksandrov$^{2}$, A. V. Andreev$^{2}$, O. Z. Umarova$^{1}$

$^{1}$‘MATI’ – Russian State Technological University Named After K.E. Tsiolkovsky, 3 Orshanskaya Str., 121552 Moscow, Russia
$^{2}$Joint-Stock Company ‘Chepetsky Mechanical Plant’, 7 Belova Str., 427622 Glazov, Udmurtskaya Republic, Russia

Received: 17.09.2015. Download: PDF

In this work, the two schemes of obtaining heat-resistant alloy based on titanium Ti$_{2}$AlNb intermetallide is considered: the triple vacuum-arc remelting (VAR—VAR—VAR) and the triple vacuum-arc remelting with the second remelting being conducted in a vacuum-arc skull furnace (VAR—VASR—VAR). As shown, the second melting scheme provides obtainment of the more homogeneous distribution for the alloying elements (primarily niobium) across the ingot section. Temperature limits of the phases’ regions are determined by a test quenching method. As shown, the alloy is of an ordered single-phase B2-state at the temperatures higher than 1050°C. At the lower temperatures, the superstructural reflections of B2-phase are not observed. Deformability of the heat-resistant alloy in as-cast condition is investigated at the elevated temperatures. As stated, the deformation of the ingot in B2-region (higher than 1050°C) can be carried out with the deformation degrees of more than 70%, and the deformation in ($O+\beta$)-region–with the deformation degrees of less than 50%. Based on the fulfilled investigations, experimental-industrial technology is developed, and the rod with diameter of 60 mm is obtained from heat-resistant alloy based on titanium Ti$_{2}$AlNb intermetallide. A two-step heat-treatment mode is developed including heating up to a high-temperature stage of 980°C and air-cooling that allows fixing a metastable $\beta$-phase in the alloy structure. The following heating up to 850°C and a 6-hour soaking result in its decomposition and formation of dispersed structure in the alloy that provides a required complex of mechanical properties.

Key words: heat-resistant titanium ortho-alloy, chemical composition, heat treatment, structure, phase composition, strength, plasticity.

URL: http://mfint.imp.kiev.ua/en/abstract/v37/i10/1313.html

DOI: https://doi.org/10.15407/mfint.37.10.1313

PACS: 61.66.Dk, 61.72.S-, 81.05.Bx, 81.10.Fq, 81.30.Fb, 81.40.Ef, 81.70.Bt

Citation: S. V. Skvortsova, A. A. Ilyin, M. G. Shtutsa, A. V. Aleksandrov, A. V. Andreev, and O. Z. Umarova, Structure and Technological Aspects of Obtaining Qualitative Semi-Finished Products from Heat-Resistant Intermetallic Ti$_{2}$AlNb-Based Alloy with Improved Properties Complex, Metallofiz. Noveishie Tekhnol., 37, No. 10: 1313—1324 (2015) (in Russian)


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