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X-RAY ANALYSIS OF HIGH PRESSURE TORSION INDUCED NANOSTRUCTURES IN TI AND NI
|Ascar R. Kilmametov 2, Ruslan Z. Valiev 1,3, Igor V. Alexandrov 1|
1. Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, K.Marks St.12, Ufa 450000, Russian Federation
High pressure torsion (HPT) is a widely used severe plastic deformation technique to form ultrafine-grain (nanostructure) states in metals and alloys. The most promising physical and mechanical properties one can expect performing new metastable nanostructures by HPT as well as combining HPT with other methods to process nanocrystalline materials. In the present work X-ray investigations including texture analysis of commercially pure Ti and Ni subjected to HPT have been presented.
It was revealed that the applied pressure growth during severe plastic deformation of commercially pure Ti leads not only to substructure refinement with increase of dislocation density and microstrain level but also to phase alpha-omega transition at room temperature. The coexistence both of alpha and omega phases (the latter known as high pressure one) in the ratio approximately of 1:3 has been obtained after high pressure removing.
Two different initial states of Ni, namely, coarse-grained and electrodeposited nanocrystalline were used for comparative studies of microstructure characteristics after HPT. Texture analysis discovered a new type of crystallite orientation distribution in nanocrystalline state. Unlike to “traditional” case of sharp axial texture forming in cubic symmetry metals prevailed pole density close to a unit has been observed. Received crystallographic texture data has been concluded to be experimental evidence of the changed plastic deformation mechanisms in nanocrystalline Ni subjected to HPT.
Presentation: poster at E-MRS Fall Meeting 2005, Symposium I, by Ascar R. Kilmametov
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-04-04 10:51 Revised: 2009-06-07 00:44