Conference Papers
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Item Microstructure, mechanical and corrosion properties of accumulative roll bonded Mg-2%Zn/anodized Al-7075 composite(Elsevier Ltd, 2018) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.S.; Arya, S.B.Multilayered composite of Mg-2%Zn/anodized Al-7075 was developed by accumulative roll bonding (ARB) of wrought Mg-2%Zn and anodized aluminium 7075 alloy. The Mg-2%Zn/anodized Al-7075 composite exhibited density of 2298 kg/m3 which is about 1.2 times lighter weight as compared to Al-7075 alloy. The electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) showed an average grain size of 1 μm and 0.73 μm in Mg-2%Zn and anodized Al-7075 layers respectively, and with high angle grain boundaries (HAGBs). Mechanical properties were evaluated by microhardness and tensile tests and found significant improvement in strength and hardness values as compared with Mg-2%Zn alloy after four pass ARB process. The multilayered composite shows better corrosion resistance as compared to rolled Mg-2%Zn alloy evaluated using using potentiodynamic polarization test. © 2017 Elsevier Ltd.Item Investigation of Cutting Force Tool Tip Temperature and Surface Roughness during Dry Machining of Spring Steel(Elsevier Ltd, 2018) Mallesha, V.; Shivananda Nayaka, H.S.Today's growing demand for steels and spring steels are widely used in industries as they possess high yield strength and their property resistance to deform easily. Spring steels have huge demand in many large scale industries, because of their applications in nuclear power plant, jet engine parts, forming tools and extrusion dies. EN47 is one of such spring steels with relatively low cost. Machinability study of EN47 material was analysed using a L27 orthogonal array (OA) for dry turning condition using TiCN/Al2O3/TiN CVD coated tungsten carbide insert with nose radius of 0.4mm. Depth of cut (d), Speed (v), feed (f) and are varied to the level-3. During machining, cutting forces and cutting temperatures was measured using Kistler based dynamometer and heat gun respectively. Surface roughness was measured by using Mitutoyo SJ201 after machining. Machined surface and chip were analysed using scanning electron microscope (SEM). Tool tip temperature, surface finish and cutting forces are optimized using Design of Experiments technique and proof trails are conducted with satisfactory results. © 2017 Elsevier Ltd.Item Comparative study of turning process on EN47 spring steel with different nose radii using statistical technique(Elsevier Ltd, 2018) Mallesha, V.; Shivananda Nayaka, H.S.Spring steel (EN47) samples are machined (turning) using Sandvik make coated tungsten carbide tool insert with different nose radii (0.4 and 0.8mm) in dry condition and the results are compared with each other. Spring steel is widely used in the manufacturing of vehicle components such as crankshaft, knuckle and leaf spring. EN47 spring steel material is relatively low cost compare to other alloy steels. Experiments are conducted based on taguchi L9 technique. Input parameters are cutting speed, feed rate and depth of cut. The corresponding output parameters are cutting force, surface roughness and tool tip temperature have been analyzed. Experimental result reveals that better surface roughness obtained with higher nose radius. ANOVA results confirm that cutting force is influenced by depth of cut (ap), surface roughness is influenced by feed rate (f) and tooltip temperature is influenced by cutting speed (Vc). Chip morphology and machined surface samples are analyzed using scanning electron microscope (SEM). © 2018 Elsevier Ltd.Item Influence of Multi Axial Forging (MAF) on Microstructure and Mechanical Properties of Cu-Ti Alloy(Elsevier Ltd, 2018) Ramesh, S.; Shivananda Nayaka, H.S.; Gopi, K.R.Multi axial forging (MAF) is one among the severe plastic deformation (SPD) processes, where large strains are imposed into the component. In the present work, as-received Cu-1.5%Ti alloy was subjected to MAF for 2 and 4 cycles at room temperature. Microstructure showed grain refinement after 2 and 4 cycles. Average grain size obtained for MAF processed samples after 2 and 4 cycles are 120 μm and 40 μm, respectively compared to initial grain size of 800 μm. The Mechanical properties were analyzed for as-received and MAF processed samples. Tensile test showed increased ultimate tensile strength (493 MPa) for MAF 4-cycle sample compared to as-received (191 MPa) condition with accumulated strain of 2.18 for 4 cycles. Increase in hardness was observed for MAF processed sample of 143 Hv for 4-cycle compared to as-received sample of 67 Hv. © 2018 Elsevier Ltd.Item Influence of cold rolling process on microstructure and mechanical properties of Cu-1.5%Ti alloy(American Institute of Physics Inc. subs@aip.org, 2018) Ramesh, S.; Shivananda Nayaka, H.S.; Anne, G.; Gopi, K.R.The effects of cold rolling on the microstructure evolution and mechanical properties of Cu-1.5%Ti alloy were investigated. The results showed that the tensile strength of the Cu-1.5%Ti alloy increased with an increase of rolling deformation at room temperature. Significant grain refinement took place during rolling process revealed in optical microstructure and transmission electron microscope analysis. XRD patterns revealed peaks indexed to Cu, Cu3-Ti2 and Cu4-Ti3 after 8-pass rolling process. Microhardness of the rolled Cu-1.5%Ti alloy layers increased incessantly with increase in the number of rolling passes. Tensile strength increased up to 294 MPa which was about 1.54 times higher than that of the cast Cu-1.5%Ti alloy. Fracture surfaces of the rolled Cu-1.5%Ti alloy revealed the dimples in the structure, which is an indication of ductile fracture. © 2018 Author(s).Item Experimental study of Mode i and Mode II interlaminar fracture toughness on aerospace structural composite T300/914(American Institute of Physics Inc. subs@aip.org, 2019) Sachin, S.; Shivananda Nayaka, H.S.; Santhosh, B.; Krishna, P.Carbon epoxy composite T300/914 which has wide applications in aerospace industries, as a structural material, has been analyzed, to determine the interlaminar fracture toughness. Laminates with a thickness of 4.6 mm, consisting of 48 layers of T300/914, are considered for estimating the inter-laminar fracture toughness. These specimens have been fabricated by hand layup method followed by controlled curing in an autoclave. Tests have been conducted in accordance with ASTM standards, for Mode I by Double Cantilever Beam (DCB) test and End Notch Flexure (ENF) test for Mode II. Pulse-Echo test results and C-Scan images of the specimens were also analyzed to locate the exact position of delamination. During the preliminary tests, it was found that the interlaminar fracture toughness varied, because of bonding of release film with the sides of the laminate. By Modified Beam Theory, Mode I and Mode II fracture toughness values of the prepared specimens were found to be 0.090 kJ/m2and 0.542 kJ/m2, respectively. It was also noted that the fracture toughness of the specimens from the same laminate varied with the degree of compaction. © 2018 Author(s).Item Microstructural and mechanical characterisation of Al-Zn-Mg-Cu alloy processed by multi-directional cryo-forging(Elsevier Ltd, 2021) Ramesh, S.; Anne, G.; Naik, G.M.; Jagadeesh, C.; Shivananda Nayaka, H.S.Aim of the present investigation is to study the microstructural and mechanical properties of Al-Zn-Mg-Cu alloy before and after multi-direction forging (MDF) at cryogenic condition up to 3 cycles. Microstructure evolution of specimen was examined using optical microscope and orientation imaging microscopy as well as X-ray diffraction. Mechanical properties were measured by tensile test and Vickers micro hardness. Microstructural investigation shows that after 3 cycle of MDF average grain size was reduced to 8 μm with low angle grain boundaries (LAGBs) and high dislocation density. Mechanical examination displays an improvement in hardness, yield strength and ultimate tensile strength is due to increases in grain boundaries and strain hardening effect. After 3 cycles of MDF process with cumulative strain ςΔϵ = 3.64 led to the formation of fine grain structure, and microhardness were observed to be 168 HV. © 2021 Elsevier Ltd. All rights reserved.