Nanocrystalline structure and phase transformation of the intermetallic compound TiAl processed by severe plastic deformation

Formation of nanocrystalline structure by severe plastic deformation has studied extensively. Although ultra fine grained structure (grain size larger than 100 nm) had been obtained in many processes such as heavy cold rolling, equal channel angular pressing (ECAP) or accumulative roll bonding (ARB), the formation of nano grained structure (< 100 nm) is limited to processes such as ball milling, shot peening or drilling. In the present study, high pressure torsion (HPT) deformation and drilling were carried out to understand the conditions necessary to obtain nano grained structure in steels. The results of HPT experiments in pure Fe showed that HPT has superior ability of strengthening and grain refinement probably due to a strain gradient but the saturation of grain refinement occurs before reaching nano grained structure. Drilling experiments in high carbon martensitic steel revelaed that nano grained ferrite forms at the drilled hole surface only when the transformation from ferrite to austenite takes place during drilling. Considering various other processes by which nano grained ferrite was produced, it is proposed that heavy strains with large strain gradients together with dynamic transformation are necessary to reach nano grained ferrite structure.

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Nanostructure formation and phase transformation in intermetallic compounds during severe plastic deformation

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2000606 ◽

2000 ◽

Vol 10 (PR6) ◽

pp. Pr6-33-Pr6-38 ◽

Cited By ~ 2

Author(s):

O. Dimitrov ◽

A. V. Korznikov ◽

G. F. Korznikova ◽

G. Tram

Keyword(s):

Plastic Deformation ◽

Phase Transformation ◽

Severe Plastic Deformation ◽

Intermetallic Compounds ◽

Nanostructure Formation

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Nanocrystalline structure formation in Al-Mg-Sc alloys during severe plastic deformation

Russian Metallurgy (Metally) ◽

10.1134/s0036029506060115 ◽

2006 ◽

Vol 2006 (6) ◽

pp. 533-540 ◽

Cited By ~ 11

Author(s):

S. V. Dobatkin ◽

V. V. Zakharov ◽

A. Yu. Vinogradov ◽

K. Kitagawa ◽

N. A. Krasil’nikov ◽

...

Keyword(s):

Plastic Deformation ◽

Severe Plastic Deformation ◽

Structure Formation ◽

Nanocrystalline Structure

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Structure and Thermal Stability of Cu after Severe Plastic Deformation

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.297-301.1312 ◽

2010 ◽

Vol 297-301 ◽

pp. 1312-1321 ◽

Cited By ~ 22

Author(s):

Vladimir V. Popov ◽

A.V. Stolbovkiy ◽

E.N. Popova ◽

V.P. Pilyugin

Keyword(s):

Thermal Stability ◽

Plastic Deformation ◽

Severe Plastic Deformation ◽

High Pressure Torsion ◽

Pure Copper ◽

Nanocrystalline Structure ◽

Transmission Electron ◽

Evolution Of Structure ◽

Stability Of Structure ◽

Thermal Stability Of

Evolution of structure of high-purity and commercially pure copper at severe plastic deformation (SPD) by high pressure torsion (HPT) at room temperature and in liquid nitrogen has been studied by transmission electron microscopy (TEM) and measurements of microhardness. Thermal stability of structure obtained by HPT has been investigated. Factors preventing from obtaining nanocrystalline structure in Cu are analyzed and possible ways of their overcoming are discussed.

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Phase Transformations of the Ti-40% Nb Alloy Under External Influence

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.683.174 ◽

2016 ◽

Vol 683 ◽

pp. 174-180 ◽

Cited By ~ 1

Author(s):

Yuri P. Sharkeev ◽

Zhanna G. Kovalevskaya ◽

Margarita A. Khimich ◽

Vladimir A. Bataev ◽

Qi Fang Zhu ◽

...

Keyword(s):

Plastic Deformation ◽

Phase Transformation ◽

Severe Plastic Deformation ◽

Phase Transformations ◽

Optical Metallography ◽

External Influence ◽

Β Phase ◽

Α Phase ◽

Pressing Operation ◽

Loading Axis

The phase transformations of the alloy Ti-40 mas % Nb after tempering and severe plastic deformation are studied. The phase transformations of the alloy according to the type and conditions of external influences are analyzed using methods of XRD, SEM and optical metallography. It is determined that inverse phase transformation of the metastable α''-phase to equilibrium β-phase is carried out after severe plastic deformation. Complete phase transformation α'' → β is typical for the mode, which consists of three pressing operation with the change of the loading axis in cramped conditions, followed by a multi-pass rolling in grooved rolls.

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