scholarly journals Effects of Strain Energy and Grain Size on Corrosion Resistance of Ultrafine Grained Fe-20%Cr Steels with Extremely low C and N Fabricated by ECAP

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Muhammad Rifai ◽  
Hiroyuki Miyamoto ◽  
Hiroshi Fujiwara
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Strain Energy ◽  
Early Stage ◽  
Pitting Potential ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
C And N ◽  
Cr Steels ◽  
Lower Temperature

Effect of strain energy and grain size on corrosion resistance of ultrafine grained (UFG) Fe-20%Cr steels with extremely low C and N fabricated by equal channel angular pressing (ECAP) was investigated. UFG structures of initial grain size of 144 nm exhibited the typical three-stage softening comprising recovery, recrystallization, and grain growth. Potentiodynamic polarization measurements were carried out with a conventional three-electrode cell to evaluate pitting potential. Pitting potential in 1000 mol·m−3NaCl solution was nobler in UFG state, but pitting potential started to decrease monotonously at lower temperature compared to hardness. The degradation of corrosion resistance in the early stage of annealing is attributed to stability change of passivation by recovery of dislocation structures inside grains and in nonequilibrium grain boundaries. We therefore conclude that nobler potentials of UFG states were realized by not only grain size reduction but also defective deformation-induced UFG.

Structure and Properties of Mg-Al-Ca Alloy after Severe Plastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 559-564 ◽  
Author(s):  
Sergey V. Dobatkin ◽  
Yuri Estrin ◽  
L.L. Rokhlin ◽  
Mikhail V. Popov ◽  
Rimma Lapovok ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Nanocrystalline Structure ◽  
Grain Structure ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Different Types ◽  
Lower Temperature

Severe plastic deformation of a Mg-Al-Ca alloy resulted in different types of grain structure. High pressure torsion (HPT) was shown to lead to the formation of a nanocrystalline structure with a grain size of 100-200 nm, while equal channel angular pressing (ECAP) produced ultrafine grained (UFG) or submicrocrystalline (SMC) structures, depending on the ECAP temperature. An UFG structure with a grain size of 2-5 -m was formed at 300°C, as distinct from a finer SMC structure with a grain size of 300-800 nm formed at a lower temperature (220°C). The possibility of increasing the strength of the alloy in the UFG condition by a factor of 1.5-2, combined with a reasonable level of ductility and enhanced functional properties was thus demonstrated. ECAP of annealed Mg-Al-Ca with the formation of UFG structure was shown to lead to increased yield strength (by a factor of 2) and enhanced tensile ductility (by a factor of 3).

Effect of Equal Channel Angular Pressing and Annealing on Corrosion Resistance of Al-Cu Alloy

2013 ◽  
Vol 803 ◽  
pp. 226-229
Author(s):  
Da Ran Fang ◽  
Chun Liu ◽  
Feng Fang Liu
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Annealing Treatment ◽  
Coarse Grained ◽  
Nacl Solution ◽  
Angular Pressing ◽  
Cu Alloy ◽  
Low Temperature Annealing ◽  
Ultrafine Grained

Al-3.9wt.%Cu alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy increases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the alloy subjected to ECAP can be improved by relief annealing.

Phase Mixture Models for Metallic Materials with Submicrometer Grain Size

2003 ◽  
Vol 791 ◽  
Author(s):  
Yuri Estrin ◽  
Hyoung Seop Kim ◽  
Mark Bush
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mixture Models ◽  
Cell Walls ◽  
Mechanical Response ◽  
Metallic Materials ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Model Predictions ◽  
Phase Mixture

ABSTRACTPhase mixture models describing the mechanical properties of submicrometer grained metals are presented. In this approach, grain boundaries or cell walls are treated as a separate phase. Two cases are considered: the mechanical response of an ultrafine grained material and the process of grain refinement by equal channel angular pressing. Model predictions with regard to the evolution of the microstructure, strength and texture are verified for Cu.

scholarly journals Study on Corrosion Behavior of Ultrafine-Grained Ti-6Al-7Nb Fabricated by Equal Channel Angular Pressing

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 950 ◽  
Author(s):  
Zequn Yu ◽  
Yuecheng Dong ◽  
Xin Li ◽  
Jingzhe Niu ◽  
Igor Alexandrov ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Equal Channel Angular Pressing ◽  
Corrosion Behavior ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Electrochemical Measurement ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

The aim of this study was to investigate the corrosion resistance of ultrafine-grained (UFG) Ti-6Al-7Nb fabricated by equal channel angular pressing (ECAP) and coarse-grained (CG) Ti- 6Al- 7Nb. The microstructure of each specimen was investigated by the electron backscattered diffraction (EBSD) method. The corrosion behavior of each specimen was determined by electrochemical measurement in Ringer’s solution. The surface corroded morphologies and oxide film formed on Ti-6Al-7Nb alloy after electrochemical measurement were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). EBSD investigation shows that the grain size of UFG Ti-6Al-7Nb decreased to ~0.4 µm, accompanied by low angle grain boundaries (LAGBs) accounting for 39%. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicated that UFG Ti-6Al-7Nb alloy possessed a better corrosion resistance. The surface corroded morphologies revealed many small and shallow corrosion pits, which can be attributed to the good compactness of the oxide film and a rapid self- repairing ability of the UFG Ti-6Al-7Nb alloy.

Grain Refinement of Copper Alloys by Equal Channel Angular Pressing

2004 ◽  
Vol 449-452 ◽  
pp. 177-180 ◽  
Author(s):  
Cha Yong Lim ◽  
Jae Hyuck Jung ◽  
Seung Zeon Han
Keyword(s):  
Grain Size ◽  
Equal Channel Angular Pressing ◽  
Copper Alloys ◽  
Metallic Materials ◽  
Fine Grained ◽  
Angular Pressing ◽  
Fine Grain ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Average Grain Size

The equal channel angular pressing (ECAP) is one of the methods to refine the grain size of metallic materials. This study investigates the effect of ECAP process on the formation of the fine grain size in oxygen free Cu and Cu alloys. The average grain size has been refined from 150 µm before ECAP to 300 nm. Microstructure was analyzed by transmission electron micrography (TEM). The diffraction pattern of the selected area confirmed the formation of ultrafine-grained structure with high angle grain boundaries after 8 cycles of ECAP. Mechanical properties such as microhardness and tensile properties of the ultra-fine grained copper materials have been investigated.

scholarly journals Impact of Equal Channel Angular Pressing on Mechanical Behavior and Corrosion Resistance of Hot-Rolled Ti-2Fe-0.1B Alloy

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5117
Author(s):  
Yanhuai Wang ◽  
Xin Li ◽  
I. V. Alexandrov ◽  
Li Ma ◽  
Yuecheng Dong ◽  
...  
Keyword(s):  
Grain Size ◽  
Corrosion Resistance ◽  
Titanium Alloy ◽  
Mechanical Behavior ◽  
Equal Channel Angular Pressing ◽  
Hot Rolling ◽  
Low Cost ◽  
Angular Pressing ◽  
Average Grain Size ◽  
Hot Rolled

In the present study, the unique bimodal grain size distribution microstructure with the ultrafine substrate and embedded macro grains was fabricated by a traditional hot-rolling process in a novel low-cost Ti-2Fe-0.1B titanium alloy, which possesses a good combination of strength (around 663 MPa) and ductility (around 30%) without any post heat treatment. Meanwhile, the mechanical behavior and corrosion resistance of hot-rolled Ti-2Fe-0.1B alloy after equal channel angular pressing (ECAP) deformation were studied. Results indicated that the average grain size decreased to 0.24 μm after 4 passes ECAP deformation, which led to the enhancement of tensile strength to around 854 MPa and good ductility to around 15%. In addition, corrosion resistance was also improved after ECAP due to the rapid self-repairing and thicker passivation film. Our study revealed that the novel low-cost titanium alloy after hot-rolling and ECAP could be used instead of Ti-6Al-4V in some industrial applications due to similar mechanical behavior and better corrosion resistance.

Structure and Fatigue Properties of the Mg Alloy AM60 Processed by ECAP

2008 ◽  
Vol 584-586 ◽  
pp. 803-808 ◽  
Author(s):  
Rinat K. Islamgaliev ◽  
Olya B. Kulyasova ◽  
Bernhard Mingler ◽  
Michael Zehetbauer ◽  
Alexander Minkow
Keyword(s):  
Grain Size ◽  
Endurance Limit ◽  
Volume Fraction ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Fatigue Endurance ◽  
Misorientation Angles

This paper reports on the microstructures and fatigue properties of ultrafine-grained (UFG) AM60 magnesium alloy processed by equal channel angular pressing (ECAP) at various temperatures. After ECAP processing, samples exhibited an increase in fatigue endurance limit, which correlates well with a decrease in grain size. In case of lowest ECAP temperature, the mean grain size is as small as 1 2m which leads to an increase in fatigue endurance limit by 70 % in comparison to coarse-grained alloy. The temperature of ECAP not only governs the grain size and misorientation angles of grain boundaries but also the volume fraction of precipitates, thus affecting the probability of twinning and grain growth after fatigue treatment.

Effect of Equal Channel Angular Pressing and Annealing on Corrosion Resistance of Cu-Zn Alloy

2013 ◽  
Vol 706-708 ◽  
pp. 78-81 ◽  
Author(s):  
D.R. Fang ◽  
F.F. Liu ◽  
Chun Liu
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Equal Channel Angular Pressing ◽  
Annealing Treatment ◽  
Coarse Grained ◽  
Nacl Solution ◽  
Angular Pressing ◽  
Low Temperature Annealing ◽  
Ultrafine Grained ◽  
Zn Alloy

Cu-32wt.%Zn alloy was subjected to equal channel angular pressing (ECAP) and subsequent low temperature annealing treatment, and the corrosion resistance of the samples was investigated by potentiodynamic polarization measurements in 3.5% NaCl solution. The results show that the corrosion rate of the ultrafine-grained alloy decreases, in comparison with the coarse-grained alloy. Meanwhile, it is noted that the corrosion resistance of the sample subjected to ECAP can be further improved by relief annealing.

Microstructure and Properties of Ti Rods Produced by Multi-Step SPD

2006 ◽  
Vol 503-504 ◽  
pp. 763-768 ◽  
Author(s):  
V.V. Latysh ◽  
Irina P. Semenova ◽  
G.H. Salimgareeva ◽  
I.V. Kandarov ◽  
Yuntian T. Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Stress ◽  
Equal Channel Angular Pressing ◽  
Thermomechanical Treatment ◽  
Ultrafine Grained Structure ◽  
Annealed State ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Cp Ti

This paper studies the effect of combined SPD treatment on microstructure and mechanical properties of semi-products out of CP Ti. The combined processing, consisting of equal-channel angular pressing and further thermomechanical treatment, produced ultrafine-grained rods out of Grade 2 CP Ti with a diameter of 6.5 mm and a length of up to 1 m. It was established that the formation of homogeneous ultrafine-grained structure in Ti rod with α-grain size of about 100 nm allowed to enhance yield stress by 200% in comparison with initial annealed state.

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