Laser surface polishing of NiCrSiBC – 60WC ceramic-metal matrix composite deposited by laser directed energy deposition process

Choudhary, Amit and Sadhu, Abhijit and Sarkar, Sagar and Nath, Ashish Kumar and Muvvala, Gopinath (2020) Laser surface polishing of NiCrSiBC – 60WC ceramic-metal matrix composite deposited by laser directed energy deposition process. Surface and Coatings Technology, 404 (126480). pp. 1-11. ISSN 0257-8972

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Abstract

Deposition of ceramic-metal matrix composite using laser directed energy deposition process presents multi-fold challenges. High melting point ceramic particles often remain partially melted and increase the roughness of the deposit, which essentially requires secondary finishing operation. Besides high surface roughness, the high gradient of thermal and physical properties between ceramic reinforcement and metal matrix introduces cracks in the composite. Therefore, in the present work, the effect of laser surface polishing and substrate heating on improving the surface quality of NiCrSiBC – 60WC ceramic-metal composite deposited by laser directed energy deposition process was investigated. The molten pool thermal history was monitored using an IR pyrometer during laser surface polishing. The effect of rate of heat input on heating rate, cooling rate, molten pool lifetime and peak temperature was investigated and correlated with the surface quality parameters viz. arithmetic surface roughness (Ra) and ten-point height (Rz). A combination of intermediate laser power and scanning speed (600 W and 2000 mm/min) resulted in proper spread of molten pool and rendered better surface finish. The surface roughness (Ra) was found to improve from 19.2 μm ± 1.36 to 1.75 μm ± 0.20. Further, different orientations of laser polishing (0°, 45°and 90°) with respect to the material deposition direction were examined, and 45° was found to yield better surface finish. Surface cracks were observed for all the cases irrespective of process parameters and cooling rates, which were mitigated by substrate pre-heating. © 2020 Elsevier B.V.

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IITH Creators:

IITH Creators	ORCiD
Muvvala, Gopinath	https://orcid.org/0000-0002-2133-3686

Item Type:

Article

Additional Information:

The corresponding author gratefully acknowledges the financial support from the Science and Engineering Research Board, under the startup research grant program (SRG/2019/000153). Authors also gratefully thank Department of Mechanical Engineering, IIT Kharagpur for extending the facilities which are financially supported by Department of Science and Technology, Government of India, under the FIST Program-2007 (SR/FIST/ETII-031/2007) and, Ministry of Human Resource Development and Department of Heavy Industries, Government of India, under the IMPRINT Program-2017 for Project-6917.

Uncontrolled Keywords:

Ceramic-metal composite; Directed energy deposition; Laser surface polishing; Molten pool thermal history; Surface roughness

Subjects:

Physics > Mechanical and aerospace
Others > Metallurgy

Divisions:

Department of Mechanical & Aerospace Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

23 Nov 2022 09:48

Last Modified:

23 Nov 2022 09:48