Faculty Publications
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Item Experimental Investigation on Effects of Wire Electro Discharge Machining of Ti50Ni45Co5 Shape Memory Alloys(Springer Netherlands rbk@louisiana.edu, 2018) Soni, H.; Narendranath, S.; Ramesh, M.R.TiNiCo shape memory alloy is most popular shape memory alloy for biomedical applications due to their outstanding properties such as shape memory effect, pseudoelasticity and transformation temperature. Machining of such kind of alloys is very difficult through conventional machining process is very difficult because they may affect their internal properties of these alloys. However conventional machining processes give poor surface quality during the machining hence non-conventional machining processes such as (wire electro discharge machining, water jet machining and electro discharge machining etc.) are more suitable for machining of such kind of alloy. From the literature it has been found that Wire electro discharge machining (WEDM) is more suitable non-conventional machining process for such kind of alloy. Present study exhibits the effects WEDM characteristics of Ti50Ni45Co5 shape memory alloy. L-9 orthogonal array has been created by using Taguchi as a design method for machining of selected alloy and machined surface characterization has been carried out at the optimized process parameters with respect to microstructures, surface topography, microhardness, XRD analysis and residual stresses. To find the optimum setting of the input process parameters a couple of optimization techniques are used, namely principal component analysis (PCA) and Gray relational analysis (GRA) technique. 125?s pulse on time (Ton), 35?s pulse off time (Toff) and 40V servo voltage (SV) were found as an optimal setting for the higher material removal rate (MRR) with better surface roughness (SR) in the present study. Moreover, characterization of the machined surface is performed with respect to microstructures, surface topography, microhardness analysis, XRD and residual stresses. Harder surface observed near the cutting edge and TiNio3 Tio2 and CuZn were noticed on the surface of machined component through XRD analysis. However, compressive residual stress has been noticed on the machined surface during WEDM process. © 2018, Springer Science+Business Media B.V., part of Springer Nature.Item Characterization and Evaluation of Joint Properties of FSWed AA6061/SiC/FA Hybrid AMCs Using Different Tool Pin Profiles(Springer, 2020) Patil, S.; Narendranath, S.; Dupadu, D.This work reports the characterization of AA6061/SiC/FA hybrid composites joined using friction stir welding (FSW). FSW was conducted by employing various tool pin profiles such as straight cylindrical (SC), tapered conical, straight square (SS) and cylindrical threaded. Microstructure and mechanical characteristics of joints were investigated using these tool pin profiles. Microstructure study of the weld joints was carried out through scanning electron microscopy and electron backscattered diffraction (EBSD) analysis. The results show equiaxed distribution of grains in the nugget zone. EBSD analysis indicates that the average grain size reduces to 3 µm after FSW with the presence of high-angle grain boundaries. Higher joint efficiency (85%) is obtained for joints obtained using SS tool pin compared to their counterparts, and SC tool yields minimum joint efficiency (77%). Overall 8% enhancement of the joint efficiency is achieved using SS tool pin profile. © 2020, The Indian Institute of Metals - IIM.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 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 Ltd