Investigation of resistance to plastic deformation and oxidation of single-crystals of CO-AL-W-Ta alloy directionally solidified with a flat front

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Abstract

Single crystals of cobalt-base alloy Co8.4Al9.4W1.9T, at. % with axial macro-segregation of tungsten and aluminum (gradient castings) were directionally solidified with a flat solidification front. Mini-specimens of different chemical compositions were cut from the obtained single-crystals at different casting heights for compression and oxidation tests. The tests performed at 900 °C showed that tungsten increases the yield strength of the alloy, while aluminum improves its oxidation resistance. It is shown that the method of directional solidification with a flat front can be effectively applied to optimize the physical and mechanical characteristics of multicomponent alloys of metals.

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About the authors

A. I. Epishin

Merzhanov Institute of Structural Macrokinetics and Materials Science RAS

Author for correspondence.
Email: a.epishin2021@gmail.com
Russian Federation, Chernogolovka, Moscow Region, 142432

N. V. Petrushin

All-Russian Scientific Research Institute of Aviation Materials, National Research Center Kurchatov Institute

Email: a.epishin2021@gmail.com
Russian Federation, Moscow, 105005

I. L. Svetlov

All-Russian Scientific Research Institute of Aviation Materials, National Research Center Kurchatov Institute

Email: a.epishin2021@gmail.com
Russian Federation, Moscow, 105005

Е. S. Elyutin

All-Russian Scientific Research Institute of Aviation Materials, National Research Center Kurchatov Institute

Email: a.epishin2021@gmail.com
Russian Federation, Moscow, 105005

D. S. Lisovenko

Ishlinsky Institute for Problems in Mechanics RAS

Email: lisovenk@ipmnet.ru
Russian Federation, Moscow, 119526

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Supplementary files

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2. Fig. 1. Gradient casting of cobalt alloy: (a) Distribution of alloying elements in zone II, MPSA; (b) Scheme of electroerosion cutting of cylindrical mini-samples of different chemical composition for compression testing.

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3. Fig. 2. Microstructure of cobalt alloy casting, SEM. (a) After two-stage heat treatment of 1300 °C/ 24 h and 700 °C/48 h; (b, c) After exposure at 900 °C for 500 h in the central (b) and near-surface (c) regions.

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4. Fig. 3. Compression and heat resistance test results for Cool-WTa alloy samples at 900 °C: (a) Effect of tungsten content on yield strength. The insert shows the heating and deformation of a mini alloy sample in a Gleeble 3800 vacuum testing machine. (b) The effect of aluminum content on heat resistance. Change in the specific gravity of the samples ∆m⁄S depending on the exposure time t.

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