Ultrafine Grained Dual Phase Steels Fabricated by Equal Channel Angular Pressing

2006 ◽  
Vol 503-504 ◽  
pp. 447-454 ◽  
Author(s):  
Dong Hyuk Shin ◽  
Woo Gyeom Kim ◽  
Jung Yong Ahn ◽  
Kyung Tae Park ◽  
Yong Suk Kim
Keyword(s):  
Strain Hardening ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Intercritical Annealing ◽  
Total Elongation ◽  
Coarse Grained ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Angular Pressing ◽  
Ultrafine Grained

Ultrafine grained (UFG) ferrite-martensite dual phase steels were fabricated by equal channel angular pressing and subsequent intercritical annealing. Their room temperature tensile properties were examined and compared to those of coarse grained counterpart. The formation of UFG martensite islands of ~ 1 μm was not confined to the former pearlite colonies but they were uniformly distributed throughout UFG matrix. The strength of UFG dual phase steels was much higher than that of coarse grained counterpart but uniform and total elongation were not degraded. More importantly, unlike most UFG metals showing negligible strain hardening, the present UFG dual phase steels exhibited extensive rapid strain hardening.

Microstructures and mechanical properties of ultrafine-grained Ti foil processed by equal-channel angular pressing and cold rolling

2003 ◽  
Vol 18 (4) ◽  
pp. 1011-1016 ◽  
Author(s):  
Y. T. Zhu ◽  
Y. R. Kolobov ◽  
G. P. Grabovetskaya ◽  
V. V. Stolyarov ◽  
N. V. Girsova ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Strain Range ◽  
Coarse Grained ◽  
Intermediate Annealing ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Heterogeneous Structures ◽  
Strength And Ductility

We processed coarse-grained Ti and equal-channel angular pressing (ECAP) processed ultrafine-grained (UFG) Ti into 20-μm-thick Ti foils by cold rolling and intermediate annealing. The foils produced from rolling the UFG Ti exhibit a homogeneous nanostructure, while foils produced from rolling the coarse-grained Ti exhibit heterogeneous structures with a mixture of nanostructured regions and coarse-grained regions. The former foils also have higher strength and ductility and exhibit uniform deformation over a larger strain range at room temperature than the latter ones. This work demonstrated the advantage and viability of producing nanostructured Ti foil by rolling ECAP-processed UFG Ti stock.

Effect of Equal-Channel Angular Pressing (ECAP) on Creep in Aluminium Alloys

2007 ◽  
Vol 539-543 ◽  
pp. 2904-2909 ◽  
Author(s):  
Vàclav Sklenička ◽  
Jiří Dvořák ◽  
Marie Kvapilová ◽  
Milan Svoboda ◽  
Petr Král ◽  
...  
Keyword(s):  
Equal Channel Angular Pressing ◽  
Aluminium Alloys ◽  
Creep Resistance ◽  
Room Temperature ◽  
Creep Behaviour ◽  
Coarse Grained ◽  
Pure Aluminium ◽  
Creep Tests ◽  
Angular Pressing ◽  
Compression Creep

This paper examines the effect of equal-channel angular pressing (ECAP) on creep behaviour of pure aluminium, binary Al-0.2wt.%Sc alloy and ternary Al-3wt.%Mg-0.2wt.%Sc alloy. The ECAP was conducted at room temperature with a die that had a 90° angle between the channels and 8 repetitive ECAP passes followed route BC. Constant stress compression creep tests were performed at 473 K and stresses ranging between 16 to 80 MPa on ECAP materials and, for comparison purposes, on the initial coarse-grained materials. The results showed that the creep resistance of the ECAP processed Al-Sc and Al-Mg-Sc alloys was markedly deteriorated with respect to unpressed coarse-grained materials.

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.

Structuration of Refractory Metals Tantalum and Niobium Using Modified Equal Channel Angular Pressing Technique

2019 ◽  
Vol 799 ◽  
pp. 103-108 ◽  
Author(s):  
Lembit Kommel ◽  
Babak Shahreza Omranpour ◽  
Valdek Mikli
Keyword(s):  
Equal Channel Angular Pressing ◽  
Coarse Grained ◽  
Uniaxial Tensile ◽  
Modified Technique ◽  
Uniaxial Tensile Strength ◽  
Large Samples ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Von Mises ◽  
Ultrafine Grained Microstructure

In the present work, we use a modified Equal Channel Angular Pressing technique for structure and properties change of Tantalum and Niobium at room temperature. The main advantage of this modified technique is the possibility to produce relatively large samples with ultrafine-grained microstructure in all volume of the workpiece by reduced deformation load up to 25% via friction decrease, and also to prevent the punch fracture under high compression stress during pressing. The various microstructures and properties were produced in metals by using different von Mises strain levels up to ƐvM = 13.8. The changes in microstructure were studied by using SEM and TEM techniques. The change of mechanical properties was measured by using various tension and hardness testing setups. We can conclude that during processing the ultrafine-grained microstructure in as-cast Nb and Ta was formed. The uniaxial tensile strength, Vickers hardness, and plasticity of Nb and Ta significantly increased as compared to coarse-grained counterparts. We believe that the relatively large workpieces of pure bulk Ta and Nb metals with improved microstructure and exploitation properties are suitable materials for the modern industry.

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.

Correlation of microstructure and strain hardening behavior in the ultrafine-grained Nb-bearing dual phase steels

2016 ◽  
Vol 678 ◽  
pp. 215-226 ◽  
Author(s):  
A. Ghatei Kalashami ◽  
A. Kermanpur ◽  
E. Ghassemali ◽  
A. Najafizadeh ◽  
Y. Mazaheri
Keyword(s):  
Strain Hardening ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Hardening Behavior ◽  
Ultrafine Grained ◽  
Strain Hardening Behavior

Unique Features of Ultrafine-Grained Microstructures in Materials Having Low Stacking Fault Energy

2010 ◽  
Vol 659 ◽  
pp. 171-176 ◽  
Author(s):  
Jenő Gubicza ◽  
Nguyen Q. Chinh ◽  
János L. Lábár ◽  
Zoltán Hegedűs ◽  
Terence G. Langdon
Keyword(s):  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Strong Dependence ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Controlled Processes ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Number Of Passes

The evolution of the microstructure during processing by equal-channel angular pressing (ECAP) in silver having extremely low stacking fault energy was studied up to 16 passes. It was shown that at high strains the contribution of twinning to deformation increased at the expense of dislocation-controlled processes. It was also found that during storage at room temperature (i.e. at the temperature of ECAP) there was a self-annealing of the severely deformed microstructure after 1 month and its degree was revealed to have a strong dependence on the number of passes.

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