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Influence of heat treatment on the mechanical and tribological properties of Incoloy 800H Superallo

Palanisamy A., Jeyaprakash N., Sivabharathi V., Sivasankaran S.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

171--185

EN

The selection and use of high strength alloys with high wear resistance (at room and high temperature) are mandatory in aerospace, nuclear, automotive, petroleum, space, furnace, and chemical industries in which Incoloy 800H superalloy is the right choice. However, this alloy is under the class of ‘difficult to cut material’ caused by their significant properties. In the present work, the heat treatment on Incoloy 800H superalloy was carried out at 1075 °C for 60 min and then the samples were cooled in the air (air cooling, AC) and furnace (furnace cooling, FC) to modify the microstructure. The mechanical and tribological behavior were examined on the heat-treated samples at room temperature to eliminate the effect of dynamic strain aging (DSA) which usually occurs at elevated temperatures in superalloys. Hardness measurement and compression tests were carried out to examine the variation of strength. Further, the dry sliding wear tests at room temperature were performed to analyze wear resistance of heat-treated specimens and compared with the as-received (AR) sample. Besides, the wear mechanism and surface roughness of worn-out specimens were analyzed. The result indicates that the air-cooled (AC) sample possessed high hardness, high compression strength, and more resistance to wear as compared to AR and FC samples. The identified wear mechanisms in AR and FC samples were abrasive, deep grooves, plastic deformation while the AC specimen exhibits mild grooves and lesser debris particles. Fractography analysis was also performed to find the nature or mode of fractures on the samples. ANOVA result indicates that the sample hardness after heat treatment has the most influencing parameter followed by the applied load on the wear rate and the coefficient of friction (CoF). The measured average roughness of the AC specimen has shown lesser value than the AR and FC specimens due to refined grain structure.

2

Comparative study of laser melting and pre‑placed Ni–20% Cr alloying over nodular iron surface

Jeyaprakash N., Yang Che-Hua, Duraiselvam Muthukannan, Sivasankaran S.

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

282--293

EN

In this study, two techniques such as laser surface melting (LSM) and laser surface alloying (LSA) were performed to protect the surface layers of nodular cast iron as it is used to manufacture different machine parts like cams, beds, camshafts, crankshafts, cylinders and engine blocks. The main objective of this research work is to examine the effects of LSM and LSA processes on phases, microstructure, hardness, wear resistance and surface roughness. The outcomes of both LSM and LSA specimens show a homogeneous structure, effective bonding of alloy powders with the base metal and crack-free surfaces. The hardness was improved 4 times (LSM) and 2.62 times (LSA) when compared with the base material. The tribological test shows improved wear resistance of LSM (8.82 × 10−7 kN) and LSA (1.32 × 10−6 kN) samples compared to the base material (4.36 × 10−6 kN). The examined wear tracks indicate that mild abrasion, adhesion and delamination were the major wear mechanisms. The reason for the enhancement of wear resistance is the refinement of microstructure, the solid solution strengthening effect and good bonding between alloy powders and base material. The LSM technique is a potential method to improve the tribological properties of industrial materials.

3

Investigations on microstructure, mechanical, and tribological behaviour of AA 7075–x wt.% TiC composites for aerospace applications

Ramkumar K. R., Sivasankaran S., Al-Mufadi F. A., Siddharth S., Raghu R.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 2

428--438

EN

This research work was dedicated to prepare AA 7075/(0, 2.5, 5 and 7.5 wt.%) TiC metal matrix composites through stir casting route. The manufactured composites were effectively characterized using various techniques such as X-ray diffraction, and advanced electron microscopes. The mechanical properties by the flexural strength and hardness results had performed and investigated elaborately. Further, the tribological properties in terms of the wear resistance and the coefficient of friction was also done and demonstrated clearly. The dispersion of TiC ceramic particles and its embedding over the ductile Al 7075 matrix was successfully obtained which exhibited excellent mechanical and surface behaviour with the function of TiC particles when compared to monolithic Al 7075 alloy. These results were due to the particulate strengthening of hard TiC ceramic particle over the soft ductile phase. In addition, X-ray diffraction results ensured the manufacturing of Al 7075-x wt.% TiC metal matrix composites successfully and no other inter-metallic phases were observed.

4

Experimental Investigation and Multi-Response Optimization in Turning of Incoloy 800H Superalloy

Palanisamy A., Selvaraj T., Sivasankaran S.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1683--1691

EN

This research work is focused on examining the turning behavior of Incoloy 800H superalloy by varying important cutting parameters. Incoloy 800H is an Iron-Nickel-Chromium based superalloy; it can withstand high temperature (810°C), high oxidization and corrosion resistance. But, it is difficult to turn in conventional machines and hence the present work was carried out and investigated. Experiments were conducted based on the standard L27 orthogonal array using uncoated tungsten inserts. The cutting force components, namely, feed force (Fx), thrust force (Fy) and cutting force (Fz); surface roughness (Ra) and specific cutting pressure (SCPR) were measured as responses and optimized using Taguchi-Grey approach. The main effects plots and analysis of mean (ANOM) were performed to check the effect of turning parameters and their significance on responses of cutting forces in all the direction (FX, FY, FZ), the surface roughness (Ra) and specific cutting pressure (SCPR). The tool wear and machined surfaces were also investigated using white light interferometer and SEM.

5

Investigations on effect of process parameters of electrodeposited Ni-Al2O3 composite coating using orthogonal array approach and mathematical modeling

Jeyaraj S., Arulshri K. P., Sivasankaran S.

Archives of Civil and Mechanical Engineering

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2016

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Vol. 16, no. 1

168--177

EN

This research article aims at preparation of nickel-aluminum oxide (Ni-Al2O3) metal matrix composite coatings that were prepared from conventional electro-deposition process. Micron sized alumina particles were deposited in nickel matrix by electro-co-deposition technique. The primary electroplating parameters of current density, pH value of electrolyte, temperature of bath, amount of ceramic particles (Al2O3) in bath, and agitation speed were considered for experimental studies. Experimental design and run orders were framed by orthogonal array of Taguchi's approach. L27 orthogonal array was chosen for experimental design based on five plating parameters and three levels. The experiments were conducted by adjusting the plating parameters and the samples were prepared from electrolytic bath. Volume fraction of Al2O3 and micro-hardness of deposits were recorded for each coated sample systematically. The mean effect studies of electroplating parameters were investigated using Taguchi's approach. The S/N ratio values for the response of micro-hardness were calculated and analyzed for significances of independent input parameters. It was found that current density, pH, temperature and agitation speed were the most significant factors. A second order quadratic equation was developed as prediction model for micro-hardness. The predicted micro-hardness values were found to be in good agreement with the experimental results.