Department of Mechanical engineering
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1921
Browse
8 results
Search Results
Item Investigation of corrosion and electrical resistance in laser welded Al-Cu joints for EV batteries(Elsevier, 2024-12) Sinhmar, SunilThis study investigates the correlation among the microstructure, electrochemical, and electrical properties of laser-welded Alsingle bondCu joints used in battery applications. Aluminium and copper thin sheets were laser welded at three power inputs (2000 W, 2100 W, and 2200 W), and joints were evaluated for their macro- and microstructural features, corrosion behaviour, electrical resistance, and temperature rise during current supply. Results indicated that higher power inputs led to deeper weld penetration and increased intermetallic formation, impacting corrosion resistance and electrical characteristics. Electrochemical impedance spectroscopy (EIS), immersion, and Tafel tests confirmed that joints welded at 2200 W exhibited superior corrosion resistance than others, and this was attributed to a uniformly mixed Alsingle bondCu region. The electric characteristics of the joints were assessed by supplying electric currents of 100 A, 150 A, and 200 A. In comparison to a weld joint developed at 2000 W, the electrical resistance of weld joints developed at 2200 W increased by 44.5 %, 37.87 %, and 39.31 % at 100 A, 150 A, and 200 A current supplies, respectively. Electrical resistance measurements revealed a direct correlation with weld quality and temperature rise, with implications on battery performance. These findings underscore the critical role of joint quality in optimizing battery performance.Item Prediction and optimization of microhardness and corrosion behaviour of CuNi-Gr composite coatings(University of Politennica, 2024) Belgamwar, Sachin U.; Rathore, Jitendra S.Graphene nanoplatelets (Gr) as fillers for alloy composite coatings has increased due to their remarkable high aspect ratio and distinctive plate-like structure. Piping, condensers and heat exchangers in seawater systems, desalination plants, marine hardware and boat hulls are expected to exhibit high wear and corrosion resistance. For this purpose, CuNi-Gr composite coatings have been fabricated using electrodeposition technique and investigated their microhardness and anti-corrosion properties. During the electrodeposition of coatings, the various process variables such as pH, current density, Gr concentration and amount of nickel sulfate have been taken into account. To achieve the full potential of CuNi-Gr composite coating in engineering applications, this study optimizes the performance of the CuNi-Gr composite coating using an orthogonal array design of a Taguchi technique. By Taguchi and regression analysis, it was found that the Gr concentration in the electrolyte is the most influencing parameter of the process for microhardness and polarization resistance of the CuNi-Gr composite coatings. It has been observed that the microhardness and polarization resistance of the composite coatings increase with the increase in the Gr content up to 400 mg/L.Item Enhancement of mechanical properties and corrosion resistance of friction stir welded joint of AA2014 using water cooling(Elsevier, 2017-01) Sinhmar, SunilAn investigation on the microstructure, mechanical properties, and corrosion behavior of friction stir welded joint of AA2014 in natural cooled (NC) and water cooled (WC) conditions have been reported. Optical microscopy, field emission scanning electron microscopy (FESEM) with Energy dispersive X-ray spectroscopy (EDS), Vicker's microhardness, tensile testing, X-ray diffraction (XRD), and electrochemical potentiodynamic polarization corrosion test (Tafel curve) were carried out to characterize the friction stir weld joints in both the cooling conditions. Water cooling resulted in higher strength and microhardness of friction stir weld joint compared to the natural cooling. The width of heat affected zone was reduced by the use of water cooling during friction stir welding (FSW) and minimum hardness zone was shifted towards weld center. The corrosion test was performed in 3.5% NaCl solution. Corrosion resistance of water cooled joint was found higher than natural cooled FSW joint. The precipitation behavior of weld nugget and heat affected zone impacts the corrosion resistance of FSW joint of AA 2014. Hardness, tensile, and corrosion properties of FSW joints produced under NC and WC conditions have been discussed in the light of microstructure.Item Effect of weld thermal cycle on metallurgical and corrosion behavior of friction stir weld joint of AA2014 aluminium alloy(Elsevier, 2019-01) Sinhmar, SunilFriction stir welding of AA2014 aluminium alloy was performed at seven different speed combinations. Weld thermal cycles were measured at all the speed parameters and corresponding peak temperatures were observed at higher tool rotation speed and lower welding speed. Hardness and tensile tests were performed to study the mechanical properties of the weld joints. Corrosion behavior was studied using immersion, Tafel and electrochemical impedance spectroscopy tests. Optical microscopy, FESEM, XRD and transmission electron microscopy were used to investigate the metallurgical behavior of the weld joints. Microhardness and corrosion resistance were found higher at low rotation speed and high traverse speed. Corrosion behavior has been discussed in light of microstructure.Item Investigation of mechanical and corrosion behavior of friction stir weld joint of aluminium alloy(Elsevier, 2019) Sinhmar, SunilFriction stir welding of AA2014 aluminium alloy was performed at 931 rpm and 41 mm/min speed. Weld joint properties were compared with the base metal. Optical microstructure and FESEM analysis with energy dispersive spectroscopy (EDS) were performed. Microhardness and tensile tests were performed to study the mechanical behavior of base metal and FSW joint. Direct current based corrosion test was carried out to study the corrosion behavior. Mechanical performance of AA2014 was reduced after the welding. Corrosion resistance of the weld joint was higher than the base metal. Presence of precipitates affected the performance of base metal and weld joint.Item Mechanical and Corrosion Behavior of Pure Aluminium Added Friction Stir Weld Joint of Aluminium Alloy(Trans Tech Publications Ltd., 2019-09) Sinhmar, SunilFriction stir welding (FSW) of AA2014 aluminium alloy was performed by sandwiching pure aluminium (Al) in the form of strip between the abutting surfaces. Mechanical and corrosion behavior of weld joint with and without pure aluminium addition was compared. Friction stir welding was carried out at rotational speed of 931 rpm and traverse speed of 41 mm/min. Pure aluminium strip of 1 mm thickness was used for incorporating Al in weld nugget zone. Microstructure analysis was carried out using optical microscope and FESEM with energy dispersive spectroscopy (EDS). Microhardness and tensile testing were performed on the weld joints. Corrosion behavior was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (Tafel) test. FESEM analysis was performed before and after corrosion test. Traces of pure aluminium strip were observed in the microstructure. The incorporated strip was found not to be uniformly distributed in the nugget zone. Pure aluminium addition reduced the extent of formation of the second phase particle in the nugget zone as compared to the normal FSW joint i.e. without Al addition. This metallurgical homogeneity resulted in better corrosion resistance of the Al added weld joint than the normal FSW joint.Item Co-deposited Zn-Cu/Gr nanocomposite: Corrosion behaviour and in-vitro cytotoxicity assessment(Taylor & Francis, 2021-04) Belgamwar, Sachin U.; Rathore, Jitendra S.Zn-Cu alloys have been considered as potential candidates for bioimplant applications due to their moderate corrosion rate and admirable mechanical properties with non-toxic nature to the human body. However, with the incorporation of advanced reinforcements, such as carbon allotropes, the properties and applicability of a Zn-Cu alloy matrix can be further enhanced. In this research, graphene (Gr) nanoplatelets reinforced Zn-Cu/Gr nanocomposites were synthesised through a modified electro-codeposition method with different concentrations of Gr (25, 50 and 100 mg L−1) in the electrolyte bath. The prepared powder samples were compacted and sintered to form pellets. The pellets were tested for mechanical and in-vitro corrosion. The obtained micro-hardness, compressive yield strength (CYS) and ultimate compressive strength (UCS) of Zn-Cu/Gr (100 mg L−1) nanocomposite are 151 HV, 340 MPs and 362 MPa with increments of 84.1%, 118% and 70.7% compared to pure Zn-Cu alloy, respectively. The reduced wear rates and friction coefficients of Zn-Cu/Gr nanocomposites are attributed to crystallite size refinement and Gr content. The electrochemical corrosion rate is reduced by 66.6% from 33 × 10−3 mm year−1 for pure Zn-Cu alloy to 11 × 10−3 mm year−1 for Zn-Cu/Gr (100 mg L−1) nanocomposites, owing to Gr barrier protection. The in-vitro cytotoxicity assessment reveals that the prepared Zn-Cu/Gr nanocomposite is non-toxic for Gr concentration up to 50 mg L−1 in the electrolyte bath. The results show that a non-toxic Zn-Cu/Gr nanocomposite with outstanding tribo-mechanical and anti-corrosion properties can be synthesised by the proposed method.Item Electro-codeposited γ-Zn-Ni/Gr composite coatings: Effect of graphene concentrations in the electrolyte bath on tribo-mechanical, anti-corrosion and anti-bacterial properties(Taylor & Francis, 2021-10) Jha, Prabhat Nath; Rathore, Jitendra S.; Belgamwar, Sachin U.In this paper, low-cost and industrially scalable γ-Zn-Ni/Gr composite coatings were electro-codeposited from an acid-sulphate based electrolyte bath. The microstructure, morphology, composition, microhardness, wear performance, corrosion resistance and anti-bacterial properties of the composite coatings were investigated in detail and compared with a Zn-Ni alloy coating. The XRD diffraction peaks of prepared coatings confirm the presence of the γ phase of the Zn-Ni alloy. Results suggested that the addition of Gr effectively reduced the crystallite size and altered the morphology. As a result, the microhardness, wear performance and corrosion resistance were improved significantly. The γ-Zn-Ni/Gr composite coating prepared with 100 mg L−1 of Gr addition in the electrolyte bath displayed the highest microhardness of 243 HV and the lowest coefficient of friction of 0.32. The anti-bacterial activity tests confirmed that the γ-Zn-Ni/Gr composite coating (from the 100 mg L−1 bath) has the highest anti-bacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).