Conference Papers

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    Flow Properties of Cast Al-Zn-Mg Alloys Subjected to Equal Channel Angular Pressing
    (Institute of Physics Publishing helen.craven@iop.org, 2018) Manjunath, G.K.; Preetham Kumar, G.V.; Udaya Bhat, K.
    Flow stress can be described as the stress necessary to continue deformation at any stage of plastic strain. The strength coefficient (K) and strain-hardening exponent (n) are the two important flow properties of the material. In the present work, flow properties of three different cast Al-Zn-Mg alloys processed by equal channel angular pressing (ECAP) were investigated. ECAP processing was carried out in a die having Φ = 120° and Ψ = 30°. After ECAP processing, significant grain refinement and increase in the hardness was observed. Compression test was used to determine the flow properties of ECAP processed samples. Force-stroke data was recorded from the compression test. Flow curves were drawn by using force-stroke data. Strength coefficient and strain-hardening exponent were determined from the log-log plot of true stress-strain curves. Significant increase in the strength coefficient was observed after ECAP processing. Also, the strength coefficient is increased when the zinc content is increased in the alloy. Strain-hardening exponent was decreased with increase in the number of ECAP passes. © Published under licence by IOP Publishing Ltd.
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    Dry sliding wear behaviour of Al-5Zn-2Mg alloy processed by severe plastic deformation
    (Elsevier Ltd, 2019) Manjunath, G.K.; Udaya Bhat, K.; Preetham Kumar, G.V.
    Equal channel angular extrusion/pressing (ECAE/P) is an effectual technique to raise the mechanical, physical properties and resistance to wear of the materials. In this research, Al-5Zn-2Mg alloy material was ECAPed in route BC at lowest temperature. Hardness of the test material was increased after ECAE/P due to microstructure refinement. To demonstrate the wear characteristics of the Al-5Zn-2Mg alloy material after ECAE/P, wear tests (in dry sliding condition) were conducted at 2 conditions (condition 1: 19.62 N load and 1 m/s sliding speed, condition 2: 39.24 N load and 2 m/s sliding speed). The wear rate and magnitude of coefficient of friction (μ) were lessened after ECAE/P. Abrasive, adhesive and oxidation wear mechanisms are the predominant wear mechanisms noticed in the ECAE/P processed billets. Along with these mechanisms relocation of iron elements from the counter body (disc) to the test material was noticed. © 2019 Elsevier Ltd.
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    Evolution of Tribological Properties of Cast Al–10Zn–2Mg Alloy Subjected to Severe Plastic Deformation
    (Springer Science and Business Media Deutschland GmbH, 2020) Manjunath, G.K.; Preetham Kumar, G.V.; Udaya Bhat, K.
    In the current investigation, tribological behaviour of the cast Al–10Zn–2Mg alloy processed by severe plastic deformation (SPD) technique was studied. In this work, one of the SPD techniques, equal channel angular pressing (ECAP) was adopted as a processing tool. ECAP was carried out in route BC and processing was attempted at the lowest temperature. After ECAP, grain structure of the material was refined and considerable improvement in the microhardness of the alloy was perceived. Mainly, wear resistance of the alloy material was enhanced with successive ECAP passes. Coefficient of friction of the alloy material was decreased with successive ECAP passes. Wear resistance of the alloy was decreased with a rise in the applied load and the sliding speed. Both at low and high load condition, abrasive wear was noticed in as-cast and homogenized specimens. Whereas in ECAPed specimens, in addition to abrasive wear, oxidation wear and adhesive wear were observed in low load and it changes to abrasive wear at high load. In the ECAPed specimens, at low load transfer of iron particles from the steel disc surface to the specimen surface was identified. © 2020, Springer Nature Singapore Pte Ltd.