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Author: search.filters.author.Bhat, K.U.Subject: search.filters.subject.Al-Zn-Mg alloy

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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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    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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    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.