A study on developing process-structure–property relationship with molten pool thermal history during laser surface remelting of Inconel 718

Jha, Arkajyoti and Shukla, Shivam and Choudhary, Amit and M, Ramji and Muvvala, Gopinath (2023) A study on developing process-structure–property relationship with molten pool thermal history during laser surface remelting of Inconel 718. Optics and Laser Technology, 157. pp. 1-11. ISSN 0030-3992

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Abstract

In the area of laser material processing, laser surface remelting has been found to be an effective method of improving surface properties such as hardness, wear, and corrosion resistance. However, the scale of improvement depends on the evolving microstructure and phases, which depend on the cooling rates. Therefore, in the present study, laser surface remelting of Inconel 718 was carried out and a process-structure–property relationship with respect to the cooling rates has been developed. During the laser surface remelting process, the molten pool thermal history i.e. cooling rate, molten pool lifetime, and solidification shelf time is monitored and estimated using an IR pyrometer. The evolution of microstructure is later correlated with these parameters. With an increase in scan speed, the cooling rate is found to increase resulting in transformation of microstructure from equiaxed grains to columnar epitaxial growth. Based on the results obtained, a process map is proposed to establish a particular type of microstructure with respect to the cooling rate. Further, the effect of cooling rate and microstructure on the surface hardness and specific wear rate has also been investigated. Both surface hardness and specific wear rate got reduced with decreasing cooling rate at a slower scan speed due to grain coarsening and an increase in elemental segregation or Laves phase formation. © 2022 Elsevier Ltd

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IITH Creators:

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

Item Type:

Article

Additional Information:

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

Uncontrolled Keywords:

Cooling rate; Inconel 718; Laser surface remelting; Microstructure evolution; Process map

Subjects:

Physics > Mechanical and aerospace

Divisions:

Department of Mechanical & Aerospace Engineering

Depositing User:

. LibTrainee 2021

Date Deposited:

19 Oct 2022 09:21

Last Modified:

19 Oct 2022 09:21