Faculty Publications
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Item Characterization of Inconel 625-SS 304 Weldments Developed by Selective Microwave Hybrid Joining Technique for Promising Applications(Springer, 2024) Kamble, D.L.; Sahu, R.K.; Narendranath, S.Production of dissimilar weldments using microwave hybrid heating is currently gaining immense impetus in the field of advanced welding. This is because such heat source could provide benefits like cost-effectiveness, rapid, volumetric, uniform and selective heating, and efficient throughput which would be significant to various industries. Till-date researchers have carried out joining of dissimilar general purpose engineering materials using microwave hybrid heat source. But attention has not been paid on the joining and characterization of dissimilar exotic-general purpose materials using the aforementioned heat source and the promising applications of the weldments. Therefore, the present article is focused on the joining of dissimilar materials- Inconel 625 and SS 304 alloys using selective microwave hybrid joining (SMHJ) technique. In SMHJ, nickel-based powder is used as a filler material, Silicon carbide (SiC) block and SiC powder are used as susceptor to increase the initial temperature. The developed weldments through SMHJ are characterized using various physico-chemical diagnostic methods. The results reveal the average micro-hardness of joint was found to be 303 ± 17 HV owing to the presence of various carbides and nitrides phase like NbC, Cr23C6, Cr2Ni3, Ni8Nb, and Fe3Ni2 in the joint zone which is evident from XRD. The average UTS of the joints found to be 448.6 MPa with an elongation of 10.93% and flexural strength observed to be 435 MPa. Further, fractography study reveals, the joint regions have mixed mode of failure. The failure was attributed to the existence of secondary phases in the joint zone. © ASM International 2023.Item Influence of Microwave Power and EWAC-1004EN Filler Size on Characteristics of Inconel 625 and SS 304 Weldments Produced Using Microwave Irradiation Hybrid Joining System(Springer Nature, 2025) Kamble, D.L.; Sahu, R.K.; S, N.; Badiger, R.I.The present study focuses on welding of Inconel 625 (exotic) and SS 304 (general purpose) dissimilar alloys using the microwave irradiation hybrid joining system and subsequent characterization of the joint processed through microwave energy. The process parameters, namely microwave power (4.4 kW and 2.2 kW) and interfacial powder EWAC 1004 EN (average particle size: 75 µm and 25 µm) are employed. The individual influence of process parameters on weldment properties is studied. The joint specimens developed at 2.2 kW power show the enhancement of ultimate tensile strength (UTS), flexural strength (FS), and average microhardness by 33.44%, 71.42% and 31.25%, respectively, in contrast to their counterparts developed at 4.4 kW keeping particle size constant. Similarly, the UTS, FS and average microhardness of the specimens developed using EWAC-1004EN powder of average particle size (APS) 25 µm found to considerably increased by 76.07%, 32.06% and 55.55%, respectively, as compared to the joints developed using 75 µm APS with constant microwave power. This enhancement in the mechanical properties is attributed to the formation of different carbide and intermetallic phases such as NbC, Cr23C6, Cr2Ni3, Ni8Nb, and FeNi in the weld region which is evident from XRD. Furthermore, the fractured specimens obtained from tensile and flexural tests are examined using FESEM. It is observed that both ductile as well as brittle fracture occurred. This mixed fracture is particularly ascribed to the presence of secondary/ intermetallic phases in the fusion region. © King Fahd University of Petroleum & Minerals 2025.Item Influence of In-house Synthesized Micro-Aegle Marmelos Polymer Concentration on Physico-Mechanical Properties of Aluminum-Based Composites(Springer Nature, 2025) Veeranaath, V.; Sahu, R.K.; Priya, I.M.For lightweight applications such as aircraft, automotive components, household, and infrastructure applications, using natural polymer fillers as reinforcement in aluminum metal matrix composites (MMCs) instead of metallic and ceramic fillers could be an attractive candidate. Therefore, the present work newly investigated the synthesis of Aegle Marmelos polymer powders (AMP) via a chemical route, followed by the fabrication of AMP-reinforced aluminum MMCs by the powder metallurgy (P/M) technique. The AMP concentration is increased in increments of 5% by weight up to 35%. The SEM results showed that the fillers are homogeneously distributed in the matrix and the bonding between them is improved. The mechanical characterization results showed that at an AMP concentration of 20 wt%, the density, hardness, and tensile strength were increased by 13%, 6.35%, and 44%, respectively, compared to the base material. In addition, a wear test is performed on the synthesized composites and the responses such as coefficient of friction and specific wear rate are individually optimized using the Taguchi approach. The common optimal parameters for the minimum coefficient of friction (0.3832) and the specific wear rate (7.83 × 10?5 mm3/Nm) are 20 wt% AMP reinforcement, sliding load 20 N, disk speed 550 rpm, and sliding time 5 min. The results of the confirmatory wear test showed that the difference between Taguchi's predicted and experimental response values ??is less than 9%. Analysis of variance results also showed that AMP reinforcement is the most significant parameter. Overall, Al-20 wt% AMP composites exhibited improved physico-mechanical properties for promising applications. © King Fahd University of Petroleum & Minerals 2024.Item Optimization of measured mechanical characteristics of selective microwave hybrid heating processed Inconel 625/ SS 304 weldments using multi-objective JAYA algorithm coupled with multi-attributes decision making R-method(Elsevier B.V., 2025) Singha, B.; Kamble, D.L.; Sahu, R.K.; Narendranath, S.; Badiger, R.I.This work focuses on the joining of Inconel-625/SS-304 using selective microwave hybrid heating (SMHH) technique. Input power, filler powder particle size, separator, and susceptor size are considered for experimentation according to the Definitive Screening Design. The multi-objectives measured are UTS, FS, and microhardness. XRD results show the intermetallic/secondary phases, and FESEM micrographs show the metallurgical bonding occurs between base metal and filler. The joint and interface region had an average microhardness of 204 ± 10 HV and 342 ± 18 HV, respectively. The UTS and FS of the weldments measured to 550 MPa and 805 MPa. MOJAYA technique is utilized for multi-objective optimization, and R-method determined the optimal process parameters. The optimal process parameters found to 2.2 kW, 25 ?m powder, 120 grit and 0.804 mm separator. The confirmation test reveals UTS ? 566 MPa, FS ? 903 MPa, and microhardness ? 365 HV, which closely matched with predicted observations. © 2024 Elsevier LtdItem Experimental and computational studies on characteristics of indigenously produced novel Aegle marmelos micro polymer reinforced aluminum composites using powder metallurgy(Korean Society of Mechanical Engineers, 2025) Veeranaath, V.; Sahu, R.K.; Priya, I.M.In recent times, the quest for an advanced composite material (polymer reinforcement in metal matrix) has become a challenge for promising industrial and household applications. Therefore, the present study focuses on the indigenous production of a novel microparticle-based Aegle marmelos natural polymer reinforced (AMNPR) aluminum composites using the powder metallurgy (P/M) technique. The results revealed that the reinforcement (AMNP) concentration had a considerable effect on the physico-mechanical, thermal, and chemical characteristics of composites. Further, in this study, TOPSIS coupled with the CRITIC method (CRITIC-TOPSIS) is adopted to convert the multiple characteristics into a closeness coefficient (Ci) response. The optimal parameters are found to be reinforcement - 20 wt. %, ball milling duration - 180 min, and speed - 300 rpm. Moreover, the Ci values predicted by the artificial neural network (ANN) model are in good agreement with the experimental values having a mean absolute error of 4.116 %. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2025.