Articles written in Sadhana
Volume 45 All articles Published: January 2020 Article ID 0023 Original Article (Mechanical Sciences)
Selection of coating material for magnesium alloy using Fuzzy AHP-TOPSIS
RESMI V PRASAD R RAJESH D THIRUMALAIKUMARASAMY
Magnesium alloys are inherently negative electrochemical potential and are very reactive compared to other engineering metals. They are prone to galvanic corrosion and micro cracks. Various coating materials or Alternatives and the required criteria and sub-criteria for the selection of Alternatives for AZ31B magnesium alloy substrate are identified by means of literature review. Criteria weight and the rank of the alternatives are usually vague and hence uncertainty prevails. The best Alternative from several potential ‘‘Candidates’’, subjectto several criteria and sub-criteria, needs to get decided. In such cases, multi criteria decision making (MCDM) techniques help in determining the MOST suitable coating material. This paper concentrates on the selection ofcoating material for the magnesium alloy substrate. The problem is subjective, uncertain and equivocal in nature. Hence in this study, fuzzy analytic hierarchy process (AHP) is applied to obtain the weights of criteria and technique for order performance by similarity to ideal solutions (TOPSIS) is utilised for ranking theAlternatives.
Volume 46 All articles Published: 30 July 2021 Article ID 0149
Sensitivity analysis and optimisation of HVOF process inputs to reduce porosity and maximise hardness of WC-10Co-4Cr coatings
RESMI V PRASAD R RAJESH D THIRUMALAIKUMARASAMY S VIGNESH S SREESABARI
This paper aims at developing an empirical relation to predict the porosity and micro-hardness, by means of High Velocity Oxy Fuel (HVOF) sprayed WC-10Co-4Cr coatings. For determining the coating performance, process parameters such as flow rate of LPG fuel, flow rate of oxygen, spray distance, flow rate ofcarrier gas and feed rate of the coating powder play a significant role. Five-factors, five-level central composite rotatable design (CCD) was employed in this analysis to reduce the number of experiments by covering all possible combinations of the process variables. A mathematical model was established to assess the porosity and microhardness of the coatings including HVOF process parameters and the appropriateness of the model was examined using analysis of variance. Using RSM, process parameter optimizations were conducted. Thecoatings produced using optimized process variables had a minimum porosity level of 0.2 Vol. percentage and a maximum hardness of 1325.26 HVx compared to other coatings. This has been confirmed by the developing response graphs and also by plotting contours. The optimization of HVOF parameters using RSM, as well as the correlation of spray variables with properties of the coating, enables the recognition of the framework of the characteristics to attain the preferred consistency of WC-10Co-4Cr coatings. Analysis of Sensitivity is alsoperformed to determine the most significant process parameter for the HVOF operation.
Volume 47 All articles Published: 3 December 2022 Article ID 0265
Multi response optimization of HVOF process parameters in low carbon steels
RESMI V `PRASAD R RAJESH D THIRUMALAIKUMARASAMY M ASHOKKUMAR S RAJAKUMAR
To fabricate the high-grade coating, HVOF is commonly used because of its potential to form dense deposits with low porosity and low oxide content. Due to higher kinetic power, a shorter dwell time, and lower flame temperatures, HVOF spraying provides a more desirable composition for dense coatings and regulates the phase transitions of the powder particles than plasma spraying. Because of the proper balance of hard-phase WC particles and the strong and durable metallic matrix cobalt chromium, WC–Co–Cr is an effective coatingmaterial for minimizing abrasive wear (Co Cr). Process variables such as liquefied petroleum gas flow rate, oxy flow rate, spray distance, carrier gas rate of flow, and feed rate of the deposition powder material all have a role in coating performance. In this work, a five-element central composite design (CCD) was utilised to reduce the number of trials by encompassing all possible combinations of process variables. A mathematical model was used to determine the porosity and micro hardness of the coatings, as well as the high velocity oxy fuelprocessing variables, and the model’s appropriateness was assessed using an analytical variable. The response surface methodology has been used to optimize process parameters (RSM).
Volume 48, 2023
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