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Microstructure formation and mechanical behaviour of titanium aluminides during torsion

TitleMicrostructure formation and mechanical behaviour of titanium aluminides during torsion
Publication TypeJournal Article
Year of Publication2016
AuthorsCao, GH, Russell, AM, Oertel, CG, Skrotzki, W
JournalPhilosophical Magazine
Volume96
Pagination2372-2384
Date Published06
Type of ArticleArticle
ISBN Number1478-6435
Accession NumberWOS:000380160400005
Keywordscreep, dynamic recrystallization, Electron microscopy, gamma, high-strain torsion, Intermetallics, Materials Science, mechanics, Metallurgical Engineering, Ordered intermetallics, phase transformation, phase-transformation, physics, severe plastic-deformation, strength, texture, tial-based alloys, torsion, transmission
Abstract

Two-phase Ti-47Al-4(Cr, Nb, Mn, Si and B) alloys (at.%) with fine-grained globular and coarse-grained lamellar structures were deformed in torsion at 1000 degrees C under 400MPa hydrostatic pressure at a maximum shear strain rate of 2x10(-4)s(-1) in a Paterson-type rock deformation machine. The evolution of microstructural characteristics during thermomechanical processing was investigated by transmission electron microscopy (TEM). It is observed that the -TiAl + (2)-Ti3Al lamellar structure breaks down, and a fine-grained duplex globular structure with a grain size on the order of 5 m develops. TEM observation indicates that the phase transformation of (2) to occurring during torsion shows diffusional character. Ordinary dislocations 1/2[110] and superdislocations 1/2[11] are observed. The microstructural and mechanical characteristics indicate that superplastic flow occurs during torsion of titanium aluminides.

DOI10.1080/14786435.2016.1200757
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Alternate JournalPhilos. Mag.