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

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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.
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    Wear Properties of ECAP-Processed AM80 Magnesium Alloy
    (Springer New York LLC barbara.b.bertram@gsk.com, 2017) Gopi, K.R.; Shivananda Nayaka, H.; Sahu, S.
    AM80 magnesium alloy was subjected to equal-channel angular pressing (ECAP), and microstructural evolution was studied using scanning electron microscope (SEM). Grain size was found to decrease up to 3 µm after four passes. An increase in number of ECAP passes led to a corresponding increase in hardness of the processed samples. Unprocessed and ECAP-processed samples were subjected to wear test using pin-on-disk wear test machine to study the wear behavior. Effects of varying loads (30 and 40 N) with sliding distances (2500 and 5000 m) were studied. The results showed reduction in wear mass loss for the ECAP-processed samples in comparison with unprocessed condition. Coefficient of friction (COF) was studied for different loads, and improvement in COF values was observed for ECAP-processed samples compared to unprocessed condition. Worn surfaces were studied using SEM and energy-dispersive x-ray spectrometer, and they exhibited plastic deformation, delamination, plowing, wear debris and oxidation in the sliding direction. X-ray diffraction analysis was conducted on the worn surfaces to identify the phases. It revealed the presence of magnesium oxide and magnesium aluminum oxide which led to oxidation wear in the sliding direction. Wear mechanism was found to be abrasive and oxidation wear. © 2017, ASM International.
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    Effect of Secondary Mg17Al12 Phase on AZ80 Alloy processed by Equal Channel Angular Pressing (ECAP)
    (Springer Netherlands, 2018) Muralidhar, M.; Narendranath, S.
    AZ80 alloy was subjected through Equal Channel Angular Pressing (ECAP) to refine the grains at three different temperatures 548 K, 573 K, and 623 K up to 4 passes for route Bc, where the specimen is rotated 90? counter-clockwise direction for each pass. In the present work, experiments have been continued with route Bc and the average grain size was obtained of 7 ?m, 9.5 ?m and 11.2 ?m for the temperatures of 548 K, 573 K, and 623 K respectively after 4 ECAP passes. The average grain size of the procured AZ80 alloy was found to be 44.5 ?m. Mechanical properties of AZ80 alloy have been improved to the corresponding various processing temperatures. X-ray diffraction studies have been done on a fourth ECAP processed specimen and compared with a zero pass specimen to know the phase transformation at different processing temperatures. Fracture behavior of each of the three materials was studied and it revealed brittle fracture by increasing the number of ECAP passes. © 2015, Springer Science+Business Media Dordrecht.
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    Microstructure Evolution in Cast Al-Zn-Mg Alloys Processed by Equal Channel Angular Pressing
    (Springer New York LLC barbara.b.bertram@gsk.com, 2018) Manjunath, G.K.; Udaya Bhat, K.; Preetham Kumar, G.V.
    In the present work, microstructure development and enhancement in the microhardness of Al-Zn-Mg alloys (with 5, 10, and 15% zinc) during equal channel angular pressing (ECAP) were investigated. Dendritic morphology was observed in the cast condition of all three alloys, and precipitates were situated along the inter-dendritic regions. After homogenization, precipitates in the inter-dendritic regions were uniformly distributed in the aluminum matrix and grain boundaries were developed. After 4 passes in route BC, large reduction in the grain size was observed. X-ray diffractometry showed that MgZn2 precipitate was developed in the ECAP-processed samples. Increase in the intensity of MgZn2 peaks was observed when the quantity of zinc is increased in the material. Also, changes in the intensity of XRD peaks were observed in ECAP-processed samples due to shear deformation. After ECAP, substantial increase in the microhardness was perceived. After four passes, microhardness increased to 109, 67, and 58% from the initial condition in A1, A2, and A3 alloys, respectively. Also, improvement in the microhardness was also observed when the quantity of zinc is increased in the material. © 2017, Springer Science+Business Media, LLC, part of Springer Nature and ASM International.