Microstructure and Properties of Ultrafine Grained Cu-0.73%Cr Alloy after High Pressure Torsion

2011 ◽  
Vol 391-392 ◽  
pp. 385-389 ◽  
Author(s):  
Kun Xia Wei ◽  
Wei Wei ◽  
Igor V. Alexandrov ◽  
Qing Bo Du ◽  
Jing Hu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Electrical Conductivity ◽  
Grain Size ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Aging Treatment ◽  
High Thermal Stability ◽  
Subsequent Aging ◽  
Ultrafine Grained

Microstructure, mechanical properties and electrical conductivity in Cu-0.73%Cr alloy after HPT process and the subsequent aging treatment have been investigated. Ultrafine grained structure with the grain size ~150 nm has been achieved after the HPT and the subsequent aging treatment. Ultrafine grains with some growth twins were preserved in the overaged state, showing high thermal stability. The peak microhardness and tensile strength of Cu-0.73%Cr alloy after the HPT was found at 480 °C for 2 hours. Electrical conductivity shows an increase trend in the different aging states.

Thermal Stability of Ultrafine-Grained Pure Titanium Processed by High-Pressure Torsion

2021 ◽  
Vol 1016 ◽  
pp. 338-344
Author(s):  
Wan Ji Chen ◽  
Jie Xu ◽  
De Tong Liu ◽  
De Bin Shan ◽  
Bin Guo ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Annealing Temperature ◽  
High Pressure Torsion ◽  
Stored Energy ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Thermal Stability Of

High-pressure torsion (HPT) was conducted under 6.0 GPa on commercial purity titanium up to 10 turns. An ultrafine-grained (UFG) pure Ti with an average grain size of ~96 nm was obtained. The thermal properties of these samples were studied by using differential scanning calorimeter (DSC) which allowed the quantitative determination of the evolution of stored energy, the recrystallization temperatures, the activation energy involved in the recrystallization of the material and the evolution of the recrystallized fraction with temperature. The results show that the stored energy increases, beyond which the stored energy seems to level off to a saturated value with increase of HPT up to 5 turns. An average activation energy of about 101 kJ/mol for the recrystallization of 5 turns samples was determined. Also, the thermal stability of the grains of the 5 turns samples with subsequent heat treatments were investigated by microstructural analysis and Vickers microhardness measurements. It is shown that the average grain size remains below 246 nm when the annealing temperature is below 500 °C, and the size of the grains increases significantly for samples at the annealing temperature of 600 °C.

Microstructure and Mechanical Properties of Ultrafine-Grained Mg-Zn-Ca Alloy

2017 ◽  
Vol 381 ◽  
pp. 39-43 ◽  
Author(s):  
Olya B. Kulyasova ◽  
Rinat K. Islamgaliev ◽  
Ruslan Z. Valiev
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
High Pressure ◽  
Chemical Composition ◽  
High Pressure Torsion ◽  
Notable Effect ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
High Microhardness ◽  
Mean Size

This paper studies the structure and mechanical properties of the Mg-1%Zn-xCa system subjected to high-pressure torsion (HPT) treatment. It was found that the chemical composition had a notable effect on the processes of grain refinement in the alloy. As is shown, HPT of Mg-1%Zn-0.005%Ca resulted in the formation of grains with a mean size of 250 nm, while HPT of the alloy with an increased content of Са up to 0.2% led to the formation of a nanostructure with a mean grain size of 90 nm. It is demonstrated that high microhardness is typical of all HPT-processed samples. The formation of fine Mg2Ca particles was established to increase the heat resistance of the alloy.

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.

Mechanical properties and electrical conductivity of ultrafine-grained aluminum consolidated by high-pressure sliding

Materialia ◽  
2020 ◽  
Vol 14 ◽  
pp. 100916 ◽  
Author(s):  
Yongpeng Tang ◽  
Takuya Komatsu ◽  
Takahiro Masuda ◽  
Makoto Arita ◽  
Yoichi Takizawa ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Ultrafine Grained

Aging Behavior of Al-Li-Cu-Mg Alloy Processed by High-Pressure Torsion

2010 ◽  
Vol 654-656 ◽  
pp. 1243-1246 ◽  
Author(s):  
Seung Won Lee ◽  
Daichi Akama ◽  
Z. Horita ◽  
Tetsuya Masuda ◽  
Shoichi Hirosawa ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Rolling Process ◽  
Mg Alloy ◽  
Age Hardening ◽  
Subsequent Aging ◽  
Solid Solution Treatment ◽  
Conventional Rolling

This study presents an application of high-pressure torsion (HPT) to an Al-Li-Cu-Mg alloy (2091). The alloy was subjected to solid solution treatment at 505oC for 30 minutes and was processed by HPT under 6 GPa for 5 revolutions at room temperature. The hardness increased with straining and saturated to a constant level at 225 Hv. Aging was undertaken on the HPT-processed alloy at 100, 150 and 190oC for the total periods up to 9.3 days. The aging treatment led to a further increase in the hardness to ~275 Hv. It is shown that the simultaneous strengthening of the alloy due to grain refinement and age hardening was successfully achieved by application of HPT and subsequent aging treatment. The enhancement of the strength is prominent when compared with the application of a conventional rolling process.

Microstructure and Thermal Stability of Copper - Carbon Nanotube Composites Consolidated by High Pressure Torsion

2012 ◽  
Vol 729 ◽  
pp. 228-233 ◽  
Author(s):  
P. Jenei ◽  
E.Y. Yoon ◽  
Jenő Gubicza ◽  
Hyoung Seop Kim ◽  
J.L. Lábár ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Dislocation Density ◽  
High Pressure Torsion ◽  
Lattice Defect ◽  
Taylor Formula ◽  
Processing Temperature ◽  
Pure Cu ◽  
Thermal Stability Of

Blends of Cu powders and 3 vol. % carbon nanotubes (CNTs), and an additional sample from pure Cu powder were consolidated by High Pressure Torsion (HPT) at room temperature (RT) and 373 K. The grain size, the lattice defect densities as well as the hardness of the pure and composite materials were determined. Due to the pinning effect of CNTs, the dislocation density is about three times larger, while the grain size is about half of that obtained in the sample consolidated from the pure Cu powder. The increase of the HPT-processing temperature from RT to 373 K resulted in only a slight increase of the grain size in the Cu-CNT composite while the dislocation density and the twin boundary frequency were reduced significantly. The flow stress obtained experimentally agrees well with the value calculated by the Taylor-formula indicating that the strength in both pure Cu and Cu-CNT composites is determined mainly by the interaction between dislocations. The addition of CNTs to Cu yields a significantly better thermal stability of the UFG matrix processed by HPT.

scholarly journals Effect of Annealing Temperature on the Microstructure and Mechanical Properties of High-Pressure Torsion-Produced 316LN Stainless Steel

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 181
Author(s):  
Yuanyuan Dong ◽  
Zhe Zhang ◽  
Zhihai Yang ◽  
Ruixiao Zheng ◽  
Xu Chen
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Annealing Temperature ◽  
High Pressure Torsion ◽  
Annealing Process ◽  
Σ Phase ◽  
316Ln Stainless Steel ◽  
Ultrafine Grained

316LN stainless steel is a prospective structural material for the nuclear and medical instruments industries. Severe plastic deformation (SPD) combined with annealing possesses have been used to create materials with excellent mechanical properties. In the present work, a series of ultrafine-grained (UFG) 316LN steels were produced by high-pressure torsion (HPT) and a subsequent annealing process. The effects of annealing temperature on grain recrystallization and precipitation were investigated. Recrystallized UFG 316LN steels can be achieved after annealing at high temperature. The σ phase generates, at grain boundaries, at an annealing temperature range of 750–850 °C. The dislocations induced by recrystallized grain boundaries and strain-induced nanotwins are beneficial for enhancing ductility. Moreover, microcracks are easy to nucleate at the σ phase and the γ-austenite interface, causing unexpected rapid fractures.

Microstructure and mechanical properties of ultrafine-grained aluminum consolidated by high-pressure torsion

2017 ◽  
Vol 682 ◽  
pp. 501-508 ◽  
Author(s):  
Mohammad Khajouei-Nezhad ◽  
Mohammad Hossein Paydar ◽  
Ramin Ebrahimi ◽  
Péter Jenei ◽  
Péter Nagy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Microstructure And Mechanical Properties ◽  
Ultrafine Grained
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