Journal Articles
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Item 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.Item Microstructure and Mechanical Properties of Cast Al-5Zn-2Mg Alloy Subjected to Equal-Channel Angular Pressing(Springer New York LLC barbara.b.bertram@gsk.com, 2018) Manjunath, G.K.; Preetham Kumar, G.V.P.; Udaya Bhat, K.; Huilgol, P.In the present work, cast Al-5Zn-2Mg alloy was processed through equal-channel angular pressing (ECAP) in route BC up to four number of passes. Microstructure and mechanical properties were investigated on processed and unprocessed materials. In cast condition, the material was composed of dendritic structure. After homogenization treatment, large-sized grains were observed. After ECAP processing, significant grain refinement was observed. After ECAP processing, high-density dislocations and high degree of misorientation between the grains were observed. In cast material, rod-shaped precipitates were observed, while, after ECAP processing, spherical-shaped precipitates were observed. ECAP processing leads to a noticeable improvement in the mechanical properties of the material. After four passes, 122% improvement in the microhardness and 135% improvement in the ultimate tensile strength of the material were observed. After three passes, a slight decrease in the mechanical properties was observed. This is attributed to the dissolution of the metastable ?? phase, annihilation of dislocations, dynamic recrystallization and texturing during ECAP processing. Brittle fracture mode was observed in tensile testing cast and homogenized samples. After ECAP processing, fracture mode was changed into shear fracture mode. © 2018, ASM International.Item Effect of zinc content on the microstructure and mechanical properties of Al-Zn-Mg alloy(Elsevier Ltd, 2022) Manjunath, G.K.; Udaya Bhat, K.; Preetham Kumar, G.V.In the present work, Aluminium-Zinc-Magnesium alloys (5 wt%, 10 wt% and 15 wt% Zinc and 2 wt% Magnesium) were prepared by casting process in a metal die. After casting process, heat treatment was conducted to the prepared alloys. To study the consequence of Zinc on the prepared alloys microstructure and mechanical properties were investigated. In as-cast state, in all three compositions, dendrite formation was noticed. While, after homogenization heat treatment, grain boundaries were noticed. Rise in the Zinc in the material leads to enhance the secondary particles. Microhardness and tension experiments were conducted to investigate the mechanical properties. Rise in the Zinc in the material leads to enhance the microhardness and tension strength. But ductility of the material declined with rise in the Zinc in the material. © 2021Item High Speed Machining for Enhancing the AZ91 Magnesium Alloy Surface Characteristics: Influence and Optimisation of Machining Parameters(Defense Scientific Information and Documentation Centre, 2022) Marakini, V.; Srinivasa Pai, P.; Udaya Bhat, K.; Thakur, D.S.; Achar, B.P.In this study, optimum machining parameters are evaluated for enhancing the surface roughness and hardness of AZ91 alloy using Taguchi design of experiments with Grey Relational Analysis. Dry face milling is performed using cutting conditions determined using Taguchi L9 design and Grey Relational Analysis has been used for the optimisation of multiple objectives. Taguchi’s signal-to-noise ratio analysis is also performed individually for both characteristics and grey relational grade to identify the most influential machining parameter affecting them. Further, Analysis of Variance is carried to see the contribution of factors on both surface roughness and hardness. Finally, the predicted trends obtained from the signal-to-noise ratio are validated using confirmation experiments. The study showed the effectiveness of Taguchi design combined with Grey Relational Analysis for the multi-objective problems such as surface characteristics studies. © 2022, DESIDOCItem Influence of Samarium (Sm) Addition on Mechanical and Tribological Performance of the Al–Mg Alloy AA5083(Springer Science and Business Media Deutschland GmbH, 2025) Aravindh, G.; Sahoo, B.; Kumar, G.V.P.; Udaya Bhat, K.Using rare earth elements as minor additives in aluminum alloys has become a promising strategy for enhancing their properties. This study specifically investigates the effects of introducing samarium (Sm) as a minor addition to the Al–Mg alloy AA5083 and analyzes the resulting changes after casting and subsequent solution treatment. The solution treatment process involved heating the alloy to 475 °C for 12 h, followed by rapid cooling in water. Various assessments, including compression testing, differential scanning calorimetry (DSC) analysis, and wear testing, were performed to evaluate the alterations of mechanical, thermal, and tribological characteristics. The results indicate that adding Sm significantly improves the mechanical strength, thermal stability, and wear resistance of the AA5083 alloy. Wear properties demonstrate that the AA5083 alloy with 1 wt.% Sm exhibited superior performance for both as-cast and solution-treated alloys compared to other alloys. These enhancements highlight the potential of incorporating rare earth microadditions to enhance the performance characteristics of aluminum alloys for a wide range of industrial applications. © American Foundry Society 2024.Item Enhancement of Microstructural, Mechanical, and Tribological Properties of AA5083 Alloy via Multi-axial Forging(Springer, 2025) Aravindh, G.; Sahoo, B.; Kumar, G.V.P.; Udaya Bhat, K.The present study investigates the influence of multi-axial forging (MAF) on the microstructure, mechanical, and wear properties of the AA5083 alloy. After solution treatment, the alloy was subjected to three MAF cycles at room temperature with a strain of 0.63 per cycle. The evolution of the microstructure was analyzed using optical microscopy, field emission gun scanning electron microscopy, and x-ray diffraction. Mechanical properties were evaluated through tensile testing, and Vicker’s micro-hardness and wear behavior of the alloys were investigated using reciprocating wear tests. The results demonstrated significant improvement in properties after the third MAF cycle, forming 8.3 ?m wide shear bands and a refined grain structure. The alloy achieved maximum hardness (130 HV), tensile strength (334 MPa), and elongation to failure (8.01%), along with a reduced strain-hardening exponent (0.27). Wear resistance showed marked enhancement, with wear volume reductions of 36%, 49%, and 21% under 1, 2, and 4 N loads, respectively. Similarly, wear rates decreased by 64%, 49%, and 15% under the same loads. These findings emphasize the MAF process's effectiveness in enhancing the mechanical and wear properties of AA5083 alloy, indicating its potential for advanced material processing techniques. © ASM International 2025.