In the present work, an attempt is made to understand and explore the repair capabilities of the Laser Directed Energy Deposition (LDED) process on Nickel based superalloy Inconel 625 (IN625). Samples were extracted from a wrought plate of IN625 and then were subjected to a fatigue test to mimic a component in service for repairing. Further, deposition was carried out on these fatigued tensile sample surfaces i.e., Top, Top & bottom, One side and Both sides. The samples were also solution-treated at 1200 °C for 90 mins. Microstructure and mechanical properties were evaluated and then compared between the different deposition strategies and sample heat-treatment conditions. Tensile properties were compared for all the three sample conditions viz. wrought alloy, as repaired and solution treated. Results indicate sound deposition with minimal porosity in all the four deposition strategies using the LDED process with a mean deposit height of 1.02 ± 0.25 mm. Microstructural analysis revealed mixed dendrite and columnar structure in the case of as-deposited samples whereas, solution treated samples exhibited recrystallized equiaxed grains with the presence of annealing twins. The as-deposited samples show a ductile mode of failure with a maximum ultimate strength of 830 MPa, yield strength of 350 MPa and elongation of 72%. For solution treated samples, a maximum ultimate tensile strength of 620 MPa, yield strength of 270 MPa and elongation of 73% were observed. The strength of the material was found to be highly influenced by the solution treatment.
Bibliographical noteFunding Information:
Jitender Chaurasia acknowledges financial support from the Ministry of Education, Government of India and National Institute of Technology Karnataka. Jitender Chaurasia also acknowledges the Laser Additive Manufacturing Laboratory, Raja Ramanna Center for Advanced Technology (RRCAT), Indore for extending their support to carry out fatigue testing and deposition using LDED process. The authors thank Dr. P. Ganesh, Mr. Prem Singh, Mr. Upendra Kumar, Mr. Saurav Kumar Nayak and Mr. Sunil Yadav for providing technical support during the experimentation at RRCAT, Indore. The authors also like to thank the Department of Mechanical Engineering, Department of Metallurgical and Materials Engineering and Central Research Facility at National Institute of Technology Karnataka for providing access to the various characterization and testing facilities.
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