Equal Channel Angular Pressing and Characterization of a Patented Eutectoid Fe-C Steel

2020 ◽  
Vol 1012 ◽  
pp. 360-365
Author(s):  
Yasmim Caroline Brito ◽  
Barbara Woinarovicz Ramos ◽  
Selauco Vurobi Junior ◽  
Ricardo Sanson Namur ◽  
Osvaldo Mitsuyuki Cintho

Equal Channel Angular (ECAP) pressing has been showed as an attractive route to produce fine and ultrafine-grained metals and alloys with high strength and fracture toughness. ECAP is a simple process for applying severe plastic deformation (SPD) to metals that can be done with common laboratory equipments (mechanical tests machines) and an adequate die. In the present work, an eutectoid steel was processed by ECAP in a 120° die. Mechanical behavior of samples deformed by ECAP was compared to the same material processed by rolling. The hardness level obtained after a single pass of ECAP was comparable to an 84% reduction by rolling in a single pass. The hardness level obtained after 1 ECAP pass on a patented steel was higher than 4 ECAP passes on the same steel without patenting. The metallographic analysis showed intense alterations on the microstructure by the ECAP processing.

Author(s):  
S Amani ◽  
Ghader Faraji ◽  
H Kazemi Mehrabadi ◽  
Mostafa Baghani

Using biodegradable magnesium microtubes for producing vascular stent have received a great deal of attention during the last decade. However, poor workability and low mechanical properties of Mg and its alloys pose an obstacle to manufacturing microtubes for stent application. In this article, a combined method including equal channel angular pressing), direct extrusion, and microtube extrusion processes are employed to produce WE43 magnesium microtubes. Thus, microtubes with an outside diameter of 3.3 mm and a wall thickness of 0.22 mm are successfully manufactured. The results demonstrate a significant improvement in mechanical properties and microstructure of the processed samples. The ultimate strength and elongation are increased from 240 MPa and 6% to 340 MPa and 20% in the final microtube, respectively. In addition, the microhardness of the final microtube is enhanced from an initial value of 85 Hv to 102 Hv and the grain size is reduced to 3.5 µm from the initial value of 135 µm. Therefore, the proposed method overcomes the poor formability of Mg alloy and can be used to fabricate high-strength microtubes with ultrafine-grained structure.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1511 ◽  
Author(s):  
Nannan Zhao ◽  
Chunyan Ban ◽  
Hongfei Wang ◽  
Jianzhong Cui

The mechanical properties and electrical conductivity of 6063 aluminum alloy subjected to equal-channel angular press (ECAP) at room temperature (RT), 200 °C, and two-step temperature schedule (TST) have been investigated in this study. The TST refers to one pass at 200 °C followed by further successive pressing at RT. It is shown that this method is effective in obtaining the combination of high strength and electrical conductivity. After two passes, the higher strength can be achieved in TST condition (328 MPa yield strength and 331 MPa ultimate tensile strength), where the changing parameter is processing temperature from the first pass at 200 °C to the second pass at RT, as compared to two passes in RT condition (241 MPa yield strength and 250 MPa ultimate tensile strength) and two passes in 200 °C condition (239 MPa yield strength and 258 MPa ultimate tensile strength). This performance could be associated with grain refinement and nanosized precipitates in TST condition. Moreover, in contrast to RT condition, a higher electrical conductivity was observed in TST condition. It reveals that high strength and electrical conductivity of 6063 aluminum alloy can be obtained simultaneously by ECAP processing in TST condition because of ultrafine-grained microstructure and nanosized precipitates.


2008 ◽  
Vol 584-586 ◽  
pp. 440-445 ◽  
Author(s):  
Miloš Janeček ◽  
Jakub Čížek ◽  
Milan Dopita ◽  
Robert Král ◽  
Ondřej Srba

Technical purity Cu (99.95 wt%) polycrystals have been processed at room temperature by equal channel angular pressing. The results of mechanical tests and the microstructure characterization by various experimental techniques are presented. The yield stress as well as the strength were shown to increase with increasing strain and exceed the respective values of a coarsegrained material. The microstructure development and its fragmentation after ECAP was investigated by the TEM and EBSD. The proportion of high angle grain boundaries was found to increase with increasing strain reaching the value of 90% after 8 ECAP passes. Two kinds of defects were identified in ECAP specimens by positron annihilation spectrometry (PAS): (a) dislocations which represent the dominant kind of defects, and (b) small vacancy clusters (so called microvoids). The main increase of defect density was found to occur during the first ECAP pass. PAS analysis indicated that in the specimens subjected to one ECAP pass the mean dislocation density ρD and the concentration of microvoids cν exceeded the values of 1014 m-2 and 10-4 at.-1, respectively. After 4 passes, the number of defects becomes saturated and practically does not change with increasing strain.


2014 ◽  
Vol 782 ◽  
pp. 404-407 ◽  
Author(s):  
Stanislav Rusz ◽  
Michal Salajka ◽  
Lubomír Čížek ◽  
Stanislav Tylšar ◽  
Jan Kedroň

Magnesium alloys has been used for a wide variety of applications, namely from the reason of their low density and high strength–to–weight ratio. The properties of magnesium alloys are connected with microstructure that is influenced by metallurgical and technological aspects. Scope of utilisation of foundry magnesium alloys is continuously being extended, so if we want to operate as competitive producers, it is necessary to investigate very actively properties of individual alloys, optimise their chemical composition, study issues of their metallurgical preparation, verify experimentally their casting properties and conditions of successful casting of castings by individual methods, including heat treatment. Recently, however, increases also utilisation of formed magnesium alloys namely application of SPD methods. The experimental part deals with hardness and structure determination of selected magnesium alloys after ECAP processing.


2012 ◽  
Vol 05 ◽  
pp. 299-306
Author(s):  
TERENCE G. LANGDON

Processing through the application of severe plastic deformation (SPD) provides a very attractive tool for the production of bulk ultrafine-grained materials. These materials typically have grain sizes in the submicrometer or nanometer ranges and they exhibit high strength at ambient temperature and, if the ultrafine grains are reasonably stable at elevated temperatures, they have a potential for use in superplastic forming operations. Several procedures are now available for applying SPD to metal samples but the most promising are Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT). This paper examines the basic principles of ECAP and HPT and describes some of the properties that may be achieved using these processing techniques.


2008 ◽  
Vol 589 ◽  
pp. 111-116 ◽  
Author(s):  
György Krállics ◽  
Arpad Fodor ◽  
Jenő Gubicza ◽  
Z. Fogarassy

An Al-6082 alloy was subjected to equal channel angular pressing (ECAP) and subsequently to conventional forming methods such as shape rolling and rotary forging. The effect of different deformation techniques on the microstructure and the mechanical properties was studied. It was found that the shape rolling and rotary forging increased further the strength of ECAP-processed samples and induced a loss of ductility.


2013 ◽  
Vol 747-748 ◽  
pp. 855-859
Author(s):  
Xiao Xue Chen ◽  
Shun Guo ◽  
Xin Qing Zhao

A series of Ti-Mo-Sn alloys with different Mo contents from 7% to 15% (wt. %) were prepared, and the effects of Mo content and thermo-mechanical treatment on their microstructural evolution and mechanical behavior were investigated. The experimental results indicated that the β to α martensite transformation can be effectively suppressed with increasing Mo content. After cold rolling treatment, superior mechanical properties and low modulus were achieved in Ti-8Mo-4Sn alloy, with tensile strength of 1108MPa, yield strength of 1003MPa and low Youngs modulus of 53GPa. The influence of severe cold deformation on the macrostructure and mechanical properties was discussed based on the characterization of X-Ray diffraction and mechanical tests. It was demonstrated that the cold rolling induced fine α martensite and high density dislocations lead to the high strength of the Ti-Mo-Sn alloys. The fine α martensite as well as the β matrix with low stability guarantee low Youngs modulus.


2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.


DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 153-161
Author(s):  
Carlos A. Meza ◽  
Ediguer E. Franco ◽  
Joao L. Ealo

Laminated composites are widely used in applications when a high strength-to-weight ratio is required. Aeronautic, naval and automotive industries use these materials to reduce the weight of the vehicles and, consequently, fuel consumption. However, the fiber-reinforced laminated materials are anisotropic and the elastic properties can vary widely due to non-standardized manufacturing processes. The elastic characterization using mechanical tests is not easy, destructive and, in most cases, not all the elastic constants can be obtained. Therefore, alternative techniques are required to assure the quality of the mechanical parts and the evaluation of new materials. In this work, the implementation of the ultrasonic through-transmission technique and the characterization of some engineering materials is reported. Isotropic materials and laminated composites of carbon fiber and glass fiber in a polymer matrix were characterized by ultrasound and mechanical tests. An improved methodology for the transit time delay calculation is reported.


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