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Author: search.filters.author.Bhat, K.U.Subject: search.filters.subject.ECAP

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    Effect of equal channel angular pressing on the microstructure and mechanical properties of Al-10Zn-2Mg alloy
    (American Institute of Physics Inc. subs@aip.org, 2018) Manjunath, G.K.; Preetham Kumar, G.V.; Bhat, K.U.
    The current investigation is focused on evaluating the mechanical properties and the microstructure of cast Al-10Zn-2Mg alloy processed through equal channel angular pressing (ECAP). The ECAP processing was attempted at minimum possible processing temperature. Microstructural characterization was carried out in optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Hardness measurement and tensile tests were employed to estimate the mechanical properties. Experimental results showed that, ECAP processing leads to noticeable grain refinement in the alloy. Reasonable amount of dislocations were observed in the ECAP processed material. After ECAP processing, precipitates nucleation in the material was detected in the XRD analysis. ECAP leads to considerable enhancement in the mechanical properties of the material. After ECAP processing, microhardness of the material is increased from 144 Hv to 216 Hv. Also, after ECAP processing the UTS of the material is increased from 140 MPa to 302 MPa. The increase in the mechanical properties of the alloy after ECAP processing is due to the dislocation strengthening and grain refinement strengthening. Finally, fracture surface morphology of the tensile test samples also studied. © 2018 Author(s).
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    Severe plastic deformation of Al-15Zn-2Mg alloy: Effect on wear properties
    (Trans Tech Publications Ltd ttp@transtec.ch, 2019) Manjunath, G.K.; Bhat, K.U.; Preetham Kumar, G.V.
    In the present work, Al-Zn-Mg alloy having highest zinc content was deformed by one of the severe plastic deformation (SPD) technique, equal channel angular pressing (ECAP) and effect of ECAP on the microstructure evolution and the wear properties were studied. ECAP was performed in a split die and the channels of the die are intersecting at an angle of 120°. ECAP was attempted at least possible temperature and the alloy was successfully ECAPed at 423 K. Below this temperature samples were failed in the first pass itself. After ECAP, significant drop in the grain size was reported. Also, ECAP leads to significant raise in the microhardness of the alloy. Predominantly, after ECAP, upsurge in the wear resistance of the alloy was noticed. To figure out the response of ECAP on the wear properties of the alloy; worn surfaces of the wear test samples were analyzed in SEM. © 2019 Trans Tech Publications Ltd, Switzerland.
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    Tensile toughness characteristics of cast Al-Zn-Mg alloys processed by equal channel angular pressing
    (Trans Tech Publications Ltd ttp@transtec.ch, 2020) Manjunath, G.K.; Bhat, K.U.; Preetham Kumar, G.V.
    In the current study, consequence of ECAP on the toughness characteristics of the Al-Zn-Mg alloys was studied. Three set of Al-Zn-Mg alloys (5, 10 and 15% Zn and 2% Mg) were selected and ECAPed. Also, consequence of zinc on the toughness characteristics of the alloy, before and after ECAP was studied. After ECAP, grain size of the alloys decreased and significant rise in the strength and ductility of the alloys were noticed. Mainly, modulus of toughness of the alloys increased with successive ECAP passes. But, the modulus of toughness of the alloys decreased with rise in the zinc in the material. © 2020 Trans Tech Publications Ltd, Switzerland.
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    Tensile Properties and Tensile Fracture Characteristics of Cast Al–Zn–Mg Alloys Processed by Equal Channel Angular Pressing
    (Springer India sanjiv.goswami@springer.co.in, 2017) Manjunath, G.K.; Preetham Kumar, G.V.; Bhat, K.U.
    In the present work, as-cast Al–5Zn–2Mg, Al–10Zn–2Mg and Al–15Zn–2Mg alloys were ECAP processed and tensile tests were carried out to determine the strength and ductility. After tensile testing, morphology of the fracture surfaces of tensile tested samples were studied. After ECAP processing, significant improvement in the yield stress and ultimate tensile strength were observed in all the three alloys. Also, yield stress and ultimate tensile strength were increased with increase in the zinc content of the material. The elongation to failure increased significantly with increase in the number of ECAP passes. SEM micrographs revealed that, the fracture surface of the cast samples of the alloys were composed of the dendritic structure, while the ECAP processed samples consisted of small size dimples. Size of the dimples were reduced with the increase in the number of ECAP passes. © 2017, The Indian Institute of Metals - IIM.
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    Precipitate evolution during severe plastic deformation of cast Al-Zn-Mg alloys and their thermal stability
    (Institute of Physics Publishing helen.craven@iop.org, 2019) Manjunath, G.K.; Huilgol, P.; Preetham Kumar, G.V.P.; Bhat, K.U.
    In the current investigation, an effort was made to understand the precipitate evolution process during equal channel angular pressing (ECAP) of an alloy composed of only aluminium, zinc and magnesium. For this purpose, three different compositions of cast Al-Zn-Mg alloys were selected and ECAP processed in route BC upto four passes. Microstructural observations indicated that, ECAP processing leads to refined structure possessing high density dislocations and large amount of grains with high angle grain boundaries. The precipitate volume in the alloys increased with increase in the zinc quantity in the alloy. Microstructural characterization through transmission electron microscope (TEM) and differential scanning calorimeter (DSC) revealed that, processing by ECAP results in structure having stable ? phase precipitates without the presence of GP zones and intermediate ?? phase precipitates. Thereby demonstrates that, ECAP process accelerates the precipitation kinetics and also shifts the morphology of the precipitates. Higher mechanical properties were noticed in the alloy containing large quantity of MgZn2 precipitates. © 2018 IOP Publishing Ltd.