Structure and Properties of Cu Alloys Alloying with Cr and Hf after Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) results in grain-subgrain structure formation in Cu0.75 %Cr alloy with the average size of structure elements of 320 ± 73 nm Addition of hafnium into the Cu-Cr alloy leads to decrease of average size down to 225±82 nm and to increase of the high angle boundaries fraction from 40% to 53%. Microhardness of the Cu-0.7 %Cr-0.9 %Hf alloy is higher, than of the Cu-0.75 %Cr alloy, as after ECAP, so after heating when the aging processes occur in the temperature interval 400–550 °С. The strength in the tension tests of the Cu-0.7 %Cr-0.9 %Hf alloy after ECAP rises in 2.2 times compared with the quenched state. The aging leads to additional strength growth by 19%.

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Development of Ultra-Fine Grained Structure in an Al-5.4%Mg-0.5%Mn Alloy Processed by ECAP

Materials Science Forum ◽

10.4028/www.scientific.net/msf.667-669.487 ◽

2010 ◽

Vol 667-669 ◽

pp. 487-492

Author(s):

Alla Kipelova ◽

Ilya Nikulin ◽

Sergey Malopheyev ◽

Rustam Kaibyshev

Keyword(s):

Plastic Deformation ◽

Structure Formation ◽

Equal Channel Angular Pressing ◽

Microstructural Evolution ◽

Coarse Grained ◽

High Angle ◽

Fine Grained ◽

Angular Pressing ◽

Fine Grained Structure ◽

Zr Alloy

Microstructural changes during equal channel angular pressing (ECAP) at the temperatures of 250 and 300°C to the strains ~4, ~8 and ~12 were studied in a coarse-grained Al-5.4%Mg-0.5%Mn-0.1%Zr alloy. At a strain of ~4, the microstructural evolution is mainly characterized by the development of well-defined subgrains within interiors of initial grains and the formation of fine grains along original boundaries. Further straining leads to increase in the average misorientation angle, the fraction of high-angle grain boundaries and the fraction of new grains. However, only at 300°C, the plastic deformation to a strain of ~12 leads to the formation of almost uniform submicrocrystalline (SMC) grained structure with an average crystallites size of ~ 0.5 m. At 250°C, the microstructure remains non-uniform and consists of subgrains and new recrystallized grains. The mechanism of new SMC structure formation after ECAP is discussed.

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Microstructure Evolution in an Al-Cu-Mg-Ag Alloy during ECAP at 300°C

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.409.41 ◽

2011 ◽

Vol 409 ◽

pp. 41-46

Author(s):

Marat Gazizov ◽

Rustam Kaibyshev

Keyword(s):

Dynamic Recrystallization ◽

Equal Channel Angular Pressing ◽

Microstructure Evolution ◽

Solution Treatment ◽

Total Strain ◽

High Angle ◽

Continuous Dynamic Recrystallization ◽

Angular Pressing ◽

Continuous Dynamic ◽

Average Size

A novel Al-Cu-Mg-Ag alloy with small additions of zirconium and scandium was subjected to equal channel angular pressing (ECAP) by using route BC at 300°C to strains ranging from ~1 to ~12. Initially, the alloy was subjected to solution treatment followed by water quenching; subsequent overageing was carried out at 380°C for 3 h. It was shown that continuous dynamic recrystallization (CDRX) occurs during ECAP resulting in partially recrystallized structure; at a total strain of ~12, the portion of high-angle boundaries (HAB) attains 50 pct., average misorientation is ~25°. Crystallites having elongated shape and an average size of ~1 μm are evolved after a total strain of ~12.

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Structure and Fatigue Properties of Cr-Ni-Ti Austenitic Steel after Equal Channel Angular Pressing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2611 ◽

2014 ◽

Vol 783-786 ◽

pp. 2611-2616 ◽

Cited By ~ 3

Author(s):

Sergey V. Dobatkin ◽

Werner Skrotzki ◽

Vladimir Terent’ev ◽

Olga Rybalchenko ◽

Andrey Belyakov ◽

...

Keyword(s):

Tensile Strength ◽

Equal Channel Angular Pressing ◽

Room Temperature ◽

Fatigue Properties ◽

Subgrain Structure ◽

Structural Elements ◽

High Angle ◽

Structural Element ◽

Angular Pressing ◽

Element Size

After equal channel angular pressing (ECAP) at room temperature in 08%C-18%Cr-10%Ni-Ti steel grain-subgrain structure with the size of structural elements of 100-250 nm, volume of high angle boundaries (HAB) about 59% and 38% of martensite is formed. ECAP at 400°C results in fully austenitic structure with the structural element size of 100-400 nm and volume of HAB ~54%. ECAP increases the ultimate tensile strength of 08%C-18%Cr-10%Ni-Ti steel by 1.5 - 2 times, the yield stress by 3.8 - 5.2 times, the fatigue limit - by 1.4 - 1.7 times, however the ductility is reduced. Fatigue strength is enhanced by the refinement of the structure and twinning in the austenite during ECAP and due to intensive dynamic twinning, partial martensitic transformation and increasing of the volume of HAB during cyclic deformation.

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Formation of High-Angle Grain Boundaries in Iron upon Cold Deformation by Equal-Channel Angular Pressing

Materials Science Forum ◽

10.4028/www.scientific.net/msf.467-470.1277 ◽

2004 ◽

Vol 467-470 ◽

pp. 1277-1282 ◽

Cited By ~ 8

Author(s):

Sergey V. Dobatkin ◽

V.I. Kopylov ◽

Reinhard Pippan ◽

O.V. Vasil'eva

Keyword(s):

Grain Boundaries ◽

Structure Formation ◽

Equal Channel Angular Pressing ◽

Cold Deformation ◽

Shear Plane ◽

Ebsd Analysis ◽

High Angle ◽

Angular Pressing

At present, the possibility of the formation of high-angle grain boundaries upon severe cold deformation, in particular, equal-channel angular (ECA) pressing is reliably proved. The structure formation upon multi-cycle ECA pressing substantially depends on the route determining the shear plane in the sample upon repeated passes. The route is defined by the rotation of the sample around its axis upon the multi-cycle ECA pressing. There are four main routes: route A, in which the sample is deformed by many passes without any rotations; route Ba, in which the sample is rotated by ± 90°; route Bc, in which the sample is sequentially rotated in the same direction by 90°and route C, in which the sample is rotated by 180° about its axis before each subsequent pass. By the methods of SEM, TEM and EBSD analysis it was shown that the fraction of high-angle boundaries in a-Fe upon cold ECA pressing with an angle of 90° between the channels and N=4 depends on the deformation route and increases according to the route sequence: Ba-C-Bc.

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Structure formation, phase transformations and properties in Cr–Ni austenitic steel after equal-channel angular pressing and heating

Materials Science and Engineering A ◽

10.1016/j.msea.2006.07.156 ◽

2007 ◽

Vol 463 (1-2) ◽

pp. 41-45 ◽

Cited By ~ 29

Author(s):

S.V. Dobatkin ◽

O.V. Rybal’chenko ◽

G.I. Raab

Keyword(s):

Phase Transformations ◽

Austenitic Steel ◽

Structure Formation ◽

Equal Channel Angular Pressing ◽

Angular Pressing ◽

Formation Phase

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Effect of Aging Treatment on Mechanical Properties and Electrical Conductivity of Cu-5.7%Cr In Situ Composite Produced by Equal Channel Angular Pressing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.344 ◽

2012 ◽

Vol 560-561 ◽

pp. 344-348 ◽

Cited By ~ 1

Author(s):

Wei Wei ◽

Kun Xia Wei ◽

Igor V. Alexandrov ◽

Qing Bo Du ◽

Jing Hu

Keyword(s):

Mechanical Properties ◽

Electrical Conductivity ◽

Equal Channel Angular Pressing ◽

Aging Treatment ◽

In Situ Composite ◽

Angular Pressing ◽

Peak Aging ◽

Average Size ◽

Equiaxed Grains

The effect of aging treatment on mechanical properties and electrical conductivity of Cu-5.7%Cr in situ composite produced by equal channel angular pressing (ECAP) was investigated here. The rotation and spreading of Cr particles was observed in Cu-5.7%Cr alloy during the ECAP, resulting in long thin in situ filaments. The equiaxed grains of the Cu phase with an average size of 200 nm were developed after eight passes of ECAP. When aging at 400~450 °C for 1 h, Cu-5.7%Cr composite after ECAP shows the maximum microhardness, and the electrical conductivity is larger than 70% of IACS. At 400 °C, the peak aging time appears for 0.5~2 h, dependent on the pre-strain for all ECAP samples. With the increase of ECAP passes, the enhancement of tensile strength due to the aging treatment declines, and even shows negative after eight passes of ECAP. The combination of ECAP and aging treatment would be a promising process to balance mechanical properties and electrical conductivity of Cu-5.7%Cr composite.

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