Corrosion fatigue crack initiation in ultrafine-grained near-α titanium alloy PT7M prepared by Rotary Swaging

JOURNAL OF ALLOYS AND COMPOUNDS

卷:790

Article

Chuvil'deev, V. N.¹  Kopylov, V. I.^1,2  Berendeev, N. N.¹  Murashov, A. A.¹  Nokhrin, A. V.¹  Gryaznov, M. Yu.¹  Shadrina, I. S.¹  Tabachkova, N. Yu.³  Likhnitskii, C. V.¹  Kotkov, D. N.¹  Tryaev, P. V.⁴ 

[1] Lobachevsky State Univ Nizhny Novgorod, 23 Gagarina Ave, Nizhnii Novgorod 603950, Russia

[2] Natl Acad Sci Belarus, Phys & Technol Inst, 10 Kuprevich St, Minsk 220141, BELARUS

[3] Natl Univ Sci & Technol MISIS, 4 Leninskiy Ave, Moscow 119049, Russia

[4] Russian Nucl Corp ROSATOM, Afrikantov OKBM JSC, 15 Burnakovsky Proezd, Nizhnii Novgorod 603074, Russia

关键词: Titanium alloys;    Fatigue;    Fine-grained structure;    Rotary swaging;    Strength;    Grain boundary;   

DOI  :  10.1016/j.jallcom.2019.03.146

来源: Elsevier

【 摘 要 】

The study focuses on corrosion fatigue processes taking place in an ultrafine-grained (UFG) near-alpha-titanium alloy Ti-2.5Al-2.6Zr (Russian industrial name PT7M) used in nuclear engineering. UFG structure formed with Rotary Swaging is found to increase resistance to corrosion fatigue. Parameters of the Basquin's equation are defined and the slope of the fatigue curve sigma(a)-lg(N) is shown to depend (nonmonotonic dependence) on the UFG alloy annealing temperature. This effect can be explained with the patterns of microstructural evolution in a UFG alloy PT7M during annealing: (1) reduced density of lattice dislocations, (2) precipitation and dissolution of zirconium nanoparticles, (3) release of alpha ''-phase particles causing internal stress fields along interphase (alpha-alpha '')-boundaries, and (4) intensive grain growth at elevated annealing temperatures. It is shown that the fatigue crack closure effect manifested as changing internal stress fields determined using XRD method may be observed in UFG titanium alloys. (C) 2019 Elsevier B.V. All rights reserved.

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