3 research outputs found
Corrosion fatigue crack initiation in ultrafine-grained near-a titanium alloy PT7M prepared by Rotary Swaging
The study focuses on corrosion fatigue processes taking place in an
ultrafine-grained (UFG) near-a-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
Sa-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 a''-phase particles causing internal stress
fields along interphase (a-a'')-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.Comment: 54 pages, 2 tables, 19 figures, 64 referance
Effect of severe plastic deformation realized by rotary swaging on the mechanical properties and corrosion resistance of near-a-titanium alloy Ti-2.5Al-2.6Zr
The research aims to analyze the impact that severe plastic deformation
arising during Rotary Swaging has on mechanical properties and corrosion
resistance of a near-a-titanium alloy Ti-2.5Al-2.6Zr (Russian industrial name
PT7M). The nature of corrosion decay in fine-grained alloys caused by hot salt
corrosion is known to vary from pit corrosion to intercrystalline corrosion at
the onset of recrystallization processes. Resistance to hot salt corrosion in a
fine-grained titanium alloy Ti-2.5Al-2.6Zr is shown to depend on the
structural-phase state of grain boundaries that varies during their migration
as a result of covering corrosive doping elements (aluminum, zirconium)
distributed in the crystal lattice of a titanium alloy.Comment: 37 pages, 15 figures, 39 reference