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Subject: search.filters.subject.Equal channel angular pressing

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    Equal channel angular processing-a modern deforming technique for quality products
    (Elsevier, 2021) Bhat K, U.K.; Bhat Panemangalore, D.B.; Bhat, S.
    The grain size plays a significant role in determining the mechanical properties of the materials. Decreasing grain size increases strength, toughness, and ductility. Due to these, a lot of research has been executed to develop deforming techniques to produce ultrafine-grained materials. Among several plastic deformation techniques available, equal channel angular pressing or processing (ECAP) produces ultra-fine grained materials with substantial amount of high angle grain boundaries. ECAP produces ultra-fine grained material with typical substructural features, which are difficult to achieve using other severe deformation techniques. This chapter presents characteristics, variables, die design, and die materials employed in the process. The chapter also presents recent developments in the domain, such as, use of finite element techniques, etc. © 2021 Elsevier Inc. All rights reserved.
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    Microstructural characterization and mechanical properties of cast Al-15Zn-2Mg alloy subjected to severe plastic deformation
    (Elsevier Ltd, 2018) Manjunath, G.K.; Udaya Bhat, K.; Preetham Kumar, G.V.
    In the present work, Al-15Zn-2Mg alloy was processed by ECAP technique for grain refinement. The ECAP processing was conducted at 150 °C. Microstructural characterization was carried out in OM, SEM, TEM and XRD. To evaluate the mechanical properties, hardness measurement and tensile tests were conducted at room temperature. Microstructural characterization showed that, ECAP processing leads to decrease in the grain size of the alloy. Also, small amount of dislocations were also observed in the ECAP processed material. After ECAP processing, precipitates nucleation in the material was identified in the XRD analysis. The strength and the hardness values were increased after ECAP processing. After ECAP processing, microhardness of the material is increased from 173 Hv to 252 Hv and the UTS of the material is increased from 166 MPa to 362 MPa. After tensile testing, fracture surface of the cast material showed dendritic structure and the fracture surface of the ECAP processed material showed dimples. © 2018 Elsevier Ltd. All rights reserved.
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    Tribological behaviour of aluminium-zinc-magnesium alloy processed by equal channel angular pressing
    (Elsevier Ltd, 2020) Manjunath, G.K.; Bhat, K.U.; Preetham Kumar, G.V.
    In the present work, tribological behaviour of the Al-5Zn-2 Mg alloy processed by equal channel angular pressing (ECAP) was studied. Initially, the alloy was prepared by die casting process. ECAP processing was carried out in a split die with an angle of 120° between two channels. ECAP processing was carried out at 150 °C in route BC upto four passes. After ECAP, noticeable decrease in the grain size was observed which leads to significant increase in the hardness and strength of the alloy. In homogenized condition, grain size of 180 mm was observed. While after four passes, grain size was reduced to 1-2 mm. After ECAP, the hardness and strength of the alloy was increased by 122% and 135%, respectively from the initial condition. Predominantly, after ECAP, noticeable decrease in the wear volume loss and coefficient friction of the material was observed. To understand the effect of ECAP on the tribological behaviour of the alloy; worn surfaces of the wear test samples were studied by using scanning electron microscope. © 2020 Elsevier Ltd. All rights reserved.
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    A review on wrought magnesium alloys processed by equal channel angular pressing
    (Inderscience Publishers, 2015) Muralidhar, M.; Narendranath, S.; Shivananda Nayaka, H.S.
    Magnesium and its alloys with severe plastic deformation (SPD) techniques are more attractive as structural parts in many industrial applications because of their advantages. In this paper, the importance of wrought magnesium alloys with their applications to accomplish the essential development of components is reviewed. In addition, the different approaches of equal channel angular pressing (ECAP) process for refining the grain size to achieve the ultrafine grained material on the bulk metals are discussed. Recent developments in the ECAP process are outlined clearly with their importance to overcome many complexities. Various factors like processing temperature of a specimen, die geometry, ram speed, back pressure and processing routes influencing during ECAP process of wrought magnesium alloys at different conditions such as channel angle and corner or outer arc angle are discussed. Finally, the properties of ECAP processed wrought alloys are outlined for improving the microstructure in structural parts. © © 2015 Inderscience Enterprises Ltd.
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    Recent progress in equal channel angular pressing of magnesium alloys starting from Segal's idea to advancements till date – A review
    (KeAi Publishing Communications Ltd., 2023) Sekar, S.; Naik, G.M.; Narendranath, S.; Desai, V.
    Lightweight materials with high strength and ductility have immense potential in revolutionizing the automobile, aerospace, bio-medical and defence sector. Magnesium and its alloys are the candidates that are best suited for application in above mentioned sectors. However, achieving combination of properties such as high strength, good ductility and relatively better corrosion resistance in Mg alloys is still challenging. Indeed, equal channel angular pressing (ECAP) is one of the promising techniques that simultaneously enhances the mechanical properties and corrosion behaviour. In this review, an effort has been made to address the influence of ECAP on microstructure, mechanical properties, corrosion and galvanic corrosion of magnesium and its alloys. The reason for deviation of Mg alloys from Hall Petch relation is clarified. The necessity of tailoring the microstructure of Mg alloys in order to achieve desired properties is elucidated. In addition, the recommendations and future directions derived from summary and outlook of review are critiqued. © 2022 The Authors
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    Forming of tubular commercial purity aluminum by ECAP
    (2012) Valder, J.; Rijesh, M.; Surendranathan, A.O.
    The equal channel angular pressing (ECAP) process is a promising technique for imparting a large plastic deformation to materials without a resultant decrease in cross-sectional area. In the present study, the suitability of this technique for the processing of tubular specimens has been investigated. Commercially pure aluminum was selected for the study. Tubular specimens were extruded to three passes using four processing routes through an ECAP die with an angle of 150 between the two intersecting channels. Sand was used as a mandrel during the pressing. Analysis of force-stroke diagram was carried out. The mechanical properties were also investigated. Improvement in mechanical properties was observed in all the routes. These investigations demonstrate that ECAP is a promising technique for improving properties of tubular materials while ensuring retention of shape (with the possibility of imparting further deformation to the specimen using the same die) and with low pressing pressures. © Taylor and Francis Group, LLC.
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    Failure Analysis of Cast Tubular Specimens of Al–5Zn–1Mg While Processing at Room Temperature by Equal Channel Angular Pressing (ECAP)
    (Springer Science and Business Media, LLC, 2014) Valder, J.; Rijesh, M.; Surendranathan, A.O.
    The ECAP process is a promising technique for imparting large plastic deformation and breaking down the ingot cast structure without a resultant decrease in cross-sectional area. In the present study, the suitability of this technique for processing cast Al–5Zn–1Mg tubular specimens at room temperature has been investigated. Tubular specimens were extruded through an ECAP die with an angle of 150° between the two intersecting channels without a back pressure. Sand was used as a mandrel during pressing. The tubular specimens failed miserably in the first pass itself. A failure analysis was carried out using SEM, and cause for failure was determined. © 2014, ASM International.
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    Microstructure evolution in AZ61 alloy processed by equal channel angular pressing
    (Hindawi Publishing Corporation 410 Park Avenue, 15th Floor, 287 pmb New York NY 10022, 2016) Muralidhar, M.; Narendranath, S.; Mashamba, M.
    Magnesium and its alloys are finding increasing use in aerospace, automobile, nuclear, electrical, and structural engineering applications because of their high strength-to-weight ratio when compared to aluminum, titanium, and steel. In this work, AZ61 wrought magnesium alloy was processed using equal channel angular pressing at three different temperatures of 483, 523, and 573 K using up to four equal channel angular pressing passes. A microstructural study was conducted by measuring the average grain size after each pass, for the three different processing temperatures. The mechanical properties of the processed samples were noted to improve due to the reduction in the grain size after each equal channel angular pressing pass. After four equal channel angular pressing passes, the average grain size of the AZ61 samples was found to be reduced to 85%, 81%, and 70% for the pressing temperatures of 483, 523, and 573 K, respectively. The tensile strength of the AZ61 alloy increased with increase in the number of equal channel angular pressing passes for each of the temperatures when compared to as-received alloy. For instance, for the processing temperatures of 483, 523, and 573 K, the tensile strength increased by 24%, 10%, and 12%, respectively, at four equal channel angular pressing passes. Also, the percentage elongation of the alloy was increased with increase in processing temperatures. Moreover, fracture topographies of the tensile surfaces are illustrated through scanning electron microcopy and reveal ductile fracture than as-received alloy for four passes at each equal channel angular pressing processing temperature. © The Author(s) 2016.
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    Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy
    (Springer New York LLC barbara.b.bertram@gsk.com, 2016) Gopi, K.R.; Shivananda Nayaka, H.S.; Sahu, S.
    Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing. © 2016, ASM International.
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    Tribological and corrosion properties of AM70 magnesium alloy processed by equal channel angular pressing
    (Cambridge University Press, 2017) Gopi, K.R.; Shivananda Nayaka, H.
    Wear and corrosion properties of AM70 magnesium alloy subjected to equal channel angular pressing (ECAP) were investigated using pin-on-disc dry sliding wear test and electrochemical impedance spectroscopy (EIS), respectively. Wear test was conducted with 30 and 40 N loads with sliding distance of 5000 m and at a constant speed of 3 m/s. Reduced coefficient of friction (COF) and wear mass loss of ECAP processed samples showed increased wear resistance. Worn surface analysis by scanning electron microscope (SEM) showed the presence of delamination, wear debris, and plowing. Energy dispersive X-ray spectrometer (EDS) revealed the occurrence of oxidation, and the wear mechanism was identified as abrasion and oxidation wear. EIS plots showed the improvement in corrosion resistance of ECAP processed magnesium alloy compared to initial condition due to grain refinement and homogeneous distribution of secondary particles. © Materials Research Society 2017.