Journal of Advanced Materials and Technologies

Journal of Advanced Materials and Technologies

Investigation of the Effect of Scan Speed and Laser Power on the Microstructure and Hardness Distribution of IN625 Deposited on a Gas Turbine Blade Using the LPBF Process

Document Type : Original Reaearch Article

Authors
Amirhossein Riazi 1
Seyed Hossein Razavi 2
Alireza Khavandi 3
Mostafa Amirjan 4
Mohsen Ostad Shabani 5
Hossein Davarzani 6
1 Ph.D. Candidate, School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran.
2 Associate Professor , School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran.
3 Professor, School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran.
4 Professor, Metallurgy Research Department, Niroo Research Institute (NRI), Tehran, Iran.
5 Assistant Professor, Department of Ceramic, Materials and Energy Research Center, Karaj, Iran.
6 MSc, MAPNA Group, TUGA, Tehran, Iran
10.30501/jamt.2025.515817.1325
Abstract
Gas turbine components are predominantly manufactured from nickel-based superalloys. Operating under harsh conditions, these parts suffer from edge wear and reduced efficiency. Given the high cost of replacement, research into the cladding, refurbishment, and reusability of damaged components is of significant importance. While most existing studies have focused on Direct Energy Deposition (DED) techniques for cladding, Laser Powder Bed Fusion (LPBF) has received less attention. This study investigates the deposition of IN625 on a non-weldable IN738 substrate using LPBF, emphasizing its advantages over DED. The mechanisms of defect formation during manufacturing, along with their evaluation and control methods, are examined. To mitigate substrate-related defects, solution annealing and homogenization heat treatments were applied. To control defects in the deposited layer, process parameters such as scan speed and laser power were varied. Microhardness, as an indicator of mechanical performance at the cladded edges, was measured. The results revealed that microhardness is influenced not only by elemental concentration gradients but also by the cooling rate and the resulting cellular structure size. Consequently, an existing model from the literature, which correlates microhardness with elemental composition, was reassessed and modified. It was found that in dissimilar material joints, within a certain energy range, hardness becomes independent of composition and is instead governed by cell size. While the existing model from the literature fails to capture this behavior, the modified equation proposed in this study accurately predicts microhardness under such conditions.
Keywords
Gas Turbine Blade
Microhardness
Cladding
IN625
IN738

Subjects

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Journal of Advanced Materials and Technologies
Volume 14, Issue 1
Spring 2025
Pages 43-61

  • Receive Date 13 April 2025
  • Revise Date 22 April 2025
  • Accept Date 21 May 2025