Submicrocrystalline Austenitic Stainless Steel Processed by Cold or Warm High Pressure Torsion

2016 ◽  
Vol 838-839 ◽  
pp. 398-403 ◽  
Author(s):  
Marina Tikhonova ◽  
Nariman Enikeev ◽  
Ruslan Z. Valiev ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Submicrocrystalline Structure ◽  
Ultrafine Grained ◽  
Different Temperatures

The formation of submicrocrystalline structure during severe plastic deformation and its effect on mechanical properties of an S304H austenitic stainless steel with chemical composition of Fe – 0.1C – 0.12N – 0.1Si – 0.95Mn – 18.4Cr – 7.85Ni – 3.2Cu – 0.5Nb – 0.01P – 0.006S (all in mass%) were studied. The severe plastic deformation was carried out by high pressure torsion (HPT) at two different temperatures, i.e., room temperature or 400°C. HPT at room temperature or 400°C led to the formation of a fully austenitic submicrocrystalline structure. The grain size and strength of the steels with ultrafine-grained structures produced by cold or warm HPT were almost the same. The ultimate tensile strengths were 1950 MPa and 1828 MPa after HPT at room temperature and 400°C, respectively.

Magnetic Characterization of SUS316L Deformed by High Pressure Torsion

2011 ◽  
Vol 239-242 ◽  
pp. 1300-1303
Author(s):  
Hong Cai Wang ◽  
Minoru Umemoto ◽  
Innocent Shuro ◽  
Yoshikazu Todaka ◽  
Ho Hung Kuo
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Austenitic Matrix ◽  
Magnetic Characterization

SUS316L austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation from g®a¢. The largest volume fraction of 70% a¢ was obtained at 0.2 revolutions per minute (rpm) while was limited to 3% at 5rpm. Pre-straining of g by HPT at 5rpm decreases the volume fraction of a¢ obtained by HPT at 0.2rpm. By HPT at 5rpm, a¢®g reverse transformation was observed for a¢ produced by HPT at 0.2rpm.

Structure and Properties of Grain Boundaries in Submicrocrystalline W Obtained by Severe Plastic Deformation

2009 ◽  
Vol 283-286 ◽  
pp. 629-638 ◽  
Author(s):  
Vladimir V. Popov ◽  
Ruslan Valiev ◽  
E.N. Popova ◽  
A.V. Sergeev ◽  
A.V. Stolbovsky ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Boundaries ◽  
High Pressure Torsion ◽  
Submicrocrystalline Structure ◽  
Emission Mössbauer Spectroscopy ◽  
Structure And Properties ◽  
Initial State

Submicrocrystalline structure of W obtained by severe plastic deformation (SPD) by high pressure torsion (5 revolutions of anvils at 4000C) and its thermal stability have been examined by TEM. Grain boundaries of submicrocrystalline W have been studied by the method of the emission Mössbauer spectroscopy in the initial state and after annealing at 400-6000С.

Microstructure and Mechanical Properties of the SPD-Processed TiNi Alloys

2013 ◽  
Vol 738-739 ◽  
pp. 486-490 ◽  
Author(s):  
Dmitriy Gunderov ◽  
Alexandr Lukyanov ◽  
Egor Prokofiev ◽  
Anna Churakova ◽  
Vladimir Pushin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Cold Rolling ◽  
High Pressure Torsion ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
First Results ◽  
Equal Channel Angular Pressure

The article represents results of influence of different severe plastic deformation (SPD) techniques on TiNi alloys. It is demonstrated that strength and shape memory effect (SME) of TiNi can be significantly enhanced due to formation of ultrafine-grained (UFG) and nanocrystalline (NC) structures by SPD. Influence of equal channel angular pressing (ECAP), high pressure torsion (HPT), multi-step SPD deformations (ECAP plus cold rolling) on structure, mechanical and functional properties of TiNi alloys is considered. There are represented first results of influence of equal channel angular pressure-Conform (ECAP-C) on TiNi alloys, which is a perspective technology for industrial fabrication of UFG metals and alloys.

Effect of SPD Processing Technique on Grain Refinement and Properties of an Austenitic Stainless Steel

2016 ◽  
Vol 879 ◽  
pp. 1957-1962 ◽  
Author(s):  
Marina Tikhonova ◽  
Iaroslava Shakhova ◽  
Rustam Kaibyshev ◽  
Andrey Belyakov
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
High Pressure Torsion ◽  
Processing Technique ◽  
Multidirectional Forging ◽  
Average Grain Size ◽  
Nanocrystalline Structures

The formation of nanocrystalline structures and mechanical properties were studied in a nitrogen-bearing 304-type stainless steel subjected to severe plastic deformation (SPD). The steel samples were processed at ambient temperature using three different methods, i.e., caliber rolling, multidirectional forging and high pressure torsion. All these techniques resulted in pronounced grain refinement. The microstructures consisting of austenite/ferrite crystallites with transverse dimensions of 50 and 30 nm evolved in the rolled and forged samples, respectively. The austenite fractions comprised approximately 0.4. In contrast, the microstructure consisted mainly of austenite with an average grain size of about 25 nm evolved after high pressure torsion. All samples of the stainless steel subjected to severe plastic deformation demonstrated significant strengthening. The ultimate tensile strengths of 2065 MPa and 1950 MPa, were obtained after rolling and high pressure torsion, respectively. The ultimate tensile strength of samples subjected to multidirectional forging was 1540 MPa.

Microstructural Evolution in the Processing of Bulk Samples Using High-Pressure Torsion

2007 ◽  
Vol 539-543 ◽  
pp. 80-85
Author(s):  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Central Zone ◽  
Thin Disk ◽  
Metallic Materials ◽  
Microstructural Refinement ◽  
Established Technique

Although high-pressure torsion (HPT) is now a well-established technique for imposing severe plastic deformation on metallic materials, the technique is generally restricted to use with thin disk samples. This paper describes experiments which were conducted to evaluate the potential for making use of HPT with bulk samples in the form of small cylinders. The experiments were performed using an Al-Mg-Sc alloy and the samples were strained under a pressure of 1 GPa at room temperature. The results demonstrate excellent microstructural refinement in the vicinity of the central zone around the periphery of the cylinders.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

The Processing of Ultrafine-Grained Materials Using High-Pressure Torsion

2007 ◽  
Vol 558-559 ◽  
pp. 1283-1294 ◽  
Author(s):  
Cheng Xu ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Metallic Materials ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Wide Range ◽  
Ultrafine Grained Materials ◽  
Thin Disks

It is now well-established that processing through the application of severe plastic deformation (SPD) leads to a significant reduction in the grain size of a wide range of metallic materials. This paper examines the fabrication of ultrafine-grained materials using high-pressure torsion (HPT) where this process is attractive because it leads to exceptional grain refinement with grain sizes that often lie in the nanometer or submicrometer ranges. Two aspects of HPT are examined. First, processing by HPT is usually confined to samples in the form of very thin disks but recent experiments demonstrate the potential for extending HPT also to bulk samples. Second, since the strains imposed in HPT vary with the distance from the center of the disk, it is important to examine the development of inhomogeneities in disk samples processed by HPT.

scholarly journals Aging Behaviour of Al-Mg-Si Alloys Subjected to Severe Plastic Deformation by ECAP and Cold Asymmetric Rolling

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
S. Farè ◽  
N. Lecis ◽  
M. Vedani
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Isothermal Aging ◽  
Room Temperature ◽  
Coarse Grained ◽  
Peak Shape ◽  
Asymmetric Rolling ◽  
Ultrafine Grained ◽  
Aging Kinetics ◽  
Reduced Intensity

A study was carried out on aging behaviour of a 6082 alloy processed by two different severe plastic deformation techniques: ECAP and asymmetric rolling. Both techniques were able to generate an ultrafine-grained structure in samples processed at room temperature. It was stated that severe straining promotes marked changes in the postdeformation aging kinetics. The peaks of β′′/β′ transition phases were anticipated and of progressively reduced intensity over the coarse grained alloy. A further peak accounting for onset of recrystallization also appeared in the most severely deformed samples. Full consistency in peak shape and position was found when comparing materials processed by ECAP and asymmetric rolling. Isothermal aging treatments performed at 180°C revealed that in the severely deformed samples, aging became so fast that the hardness curves continuously decreased due to overwhelming effects of structure restoration. On the contrary, aging at 130°C offers good opportunities for fully exploiting the precipitate hardening effects in the ultrafine-grained alloy.

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