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A. R. Vinod ¹, C. K. Srinivasa ¹, R. Keshavamurthy ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Direct Metal Deposition (DMD) is an additive manufacturing process for fabrication of metal parts directly from CAD model using high power lasers as heat source. In this paper, bronze nickel material was deposited on steel substrate by DMD process. Laser power was varied from 100 to 300 W in steps of 50. Laser scan speed, powder flow rate, nozzle stand-off and step-over were maintained at 165 mm/min, 1.2 g/min, 10 mm and 0.15 mm respectively. Laser power had a significant influence on the quality of joint between bronze nickel and steel.

Keywords

Additive Manufacturing, DMD, Laser, Dissimilar Materials.

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H. M. Mallikarjuna ¹, C. S. Ramesh ², Praveennath G. Koppad ³, K. T. Kashyap ⁴, R. Keshavamurthy ⁵

Affiliations
1 Department of Mechanical Engineering, Government Engineering College, K. R. Pet- 571426, Karnataka, IN
2 Department of Mechanical Engineering, Alliance College of Engineering and Design, Anekal,Bangalore - 562106 Karnataka, IN
3 Research and Development, Rapsri Engineering Products Company Ltd, Ramanagar, Bangalore - 562112, Karnataka, NA
4 Department of Mechanical Engineering, Atria Institute of Technology, Bangalore - 560024, Karnataka, IN
5 Department of Mechanical Engineering, Dayananda Sagar College of Engineering, Bangalore - 560078, Karnataka, IN

Abstract

The main objective is to enhance the mechanical properties of copper without losing their inherent electrical conductivity. This paper reports on the effect of Multiwalled Carbon Nanotubes (MWCNTs) and Silicon Carbide (SiC) reinforcement addition on microstructure, microhardness and electrical properties of copper-based hybrid nanocomposite. Hybrid nanocomposites have been synthesised by powder metallurgy technique which involves blending of composite powder, compaction, sintering followed by hot pressing. Microstructural characterizations of prepared hybrid nanocomposites were carried out using optical and Scanning Electron Microscope (SEM). Developed nanocomposites were also subjected to density measurement, microhardness test and electrical conductivity studies. Optical and SEM images reveal that SiC particles and MWCNTs were dispersed uniformly within the copper matrix. The densities of nanocomposites were significantly reduced owing to low densities of MWCNTs and SiC. An improvement in hardness of about 1.5 times has been observed for nanocomposites when compared with pure copper prepared under similar conditions. However, reduction in electrical conductivity of nanocomposites was observed due to grain refinement caused by multiple reinforcements and porosity. The developed hybrid nanocomposites have the potential as material candidates for self-lubricating bearings and bushes.

Keywords

Carbon Nanotubes, Copper, Hybrid Nanocomposites, Microhardness, Powder Metallurgy, Silicon carbide

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