Metallurgical Engineering

Metallurgical Engineering

Investigation of microstructure and mechanical properties of nickel based superalloy IN738LC deposited by laser Cladding

Document Type : Research Paper

Author
Ali Mohammad Kolagar
Research and development Manager at MavadKaran Engineering Company
10.22076/me.2019.83905.1182
Abstract
Precipitation-hardened nickel based superalloys are very difficult to weld in a defect-free manner due to the formation of hot cracks in the weld metal as well as liquation cracks in the heat affected zone. Laser Cladding has been recognized as the one of the most attractive and promising state of the art welding to improve weld quality and repair high cost components such as industrial turbine blades. In this study, IN625 used as the filler was deposited on IN738LC mechanical samples by laser. The microstructure and metallurgical defects such as oxide phases, porosities and cracks were investigated by optical microscope and scanning electron microscope. The low oxide phase and porosity were observed at the deposited layer. Furthermore, the hardness and tensile properties of the base metal and the deposited samples were evaluated at room temperature. The results have shown that the yield stress and tensile strength of the deposited samples campare well with base material (1.2%, 3.2%, respectively) while the average values of Hardness and ductility decreased significantly (11.0% , 33.3%, respectively).
Keywords
"Laser Cladding"
"Gas turbine blade Repairing"
"IN738LC Superalloy"
 [1].R. A. Steven & P. E. J. Flewith,“Intermediate Regenerative Heat Treatment For Extending The Creep Life of  Superalloy IN738”, Mataterial Scienec and Engineering, 1981.
[2]. C. T. Sims, N. S. Stolloff, W. C. Hagel, “Superalloys II”, John Wiley and Sons,  pp. 97-123, 1987.
[3]. H. I. Kim, H. Sun Park, J. M. Koo, “Evaluation of welding characteristics for manual overlay andlaser cladding materials in gas turbine blades”, Journal of Mechanical Science and Technology 26 (7), 2012.  
[4]. J. O. Aina, “A study of laser weldability of IN738 nickel based superalloy in a new pre-weld heat treatment condition”, Master of science thesis, University of Manitoba, 2014.
[5]. L. Shepeleva, B. Medres, W.D. Kaplan, M. Bamberger, A. Weisheit, “Laser Cladding of Turbine Blades”, Surface and Coatings Technology, 2000.
[6]. Sulzer Technical Review, “Laser Welding to Indasterial gas Turbine Components”, 2004.
[7]. W. H. Syed, A. J. Pinkerton, L. Li, “A comparative study of wire feeding and powder feedingin direct diode laser deposition for rapid prototyping”, Applied Surface Science, 2005.
[8]. ASTM E8/E8m-09,“Standard Test Methods for Tension Testing of Metallic Materials”, 2010.
[9]. Elbar Standard, “Material IN738LC, Investment Vacuum Casting”, EPS 040, 1985.
 [10]. M. Gaeumann, C. Bezençon, P. Canalis, P & W. Kurz,”Single-Crystal Laser Deposition of Superalloys: Processing-Microstructure Maps”, Acta Material, Vol.49, pp.1051–1062, 2001.
[11]. J. C. Lippold, S. D. Kiser, and J. N. DuPont, “Welding metallurgy and weldability of nickel-base alloys”, John Wiley & Sons, New York, 2009.
[12]. Minlin Zhong, Hongqing Sun, Wenjin Liu, Xiaofeng Zhu, Jinjiang He,“Boundary liquation and interface cracking characterization in laser deposition of Inconel 738 on directionally solidified Ni-based superalloy”, Scripta Materialia, PP.159–164, 2005.
[13]. J. N. Dupont, J. C. Lippold, & S. D. Kiser, “Welding Metallurgy and Weldabillity of Nickel-Base Alloys", Wiley and Sons, New York (NY), 2009.
[14]. J. Chen and L. Xue, “Process-Induced Microstructural Characteristics Of laser Consolidated IN-738 Superalloy”, Material Science and Engineering, A 527, pp.7318–7328, 2010.
  [15]. O. A. Ojo & M. C. Chaturvedi, “Liquation Microfissuring in the Weld Heat-Affected Zone of an Overaged Precipitation-Hardened Nickel-Base Superalloy”, Metallurgical and Materials Transactions A, Vol. 38, pp. 356-369, 2007.
[16].     O. A. Ojo, N. L. Richards & M. C. Chaturvedi, “Liquid Film Migration of Constitutionally Liquated γ′ in Weld Heat Affected Zone (HAZ) of IN738LC Superalloy”,  Scripta Materialia, Vol. 51, pp. 141-146, 2004.
[17].     O. A. Ojo, N. L. Richards & M. C. Chaturvedi, “Contribution of Constitutional Liquation of Gamma Prime Precipitate to Weld HAZ Cracking of Cast IN738LC  Superalloy”,Scripta Materialia, Vol. 50, pp. 641-646, 2004.
 [18]. K. R. Vishwakarma, N. L. Richards, & M. C. Chaturvedi, “Microstructural Analysis of Fusion and Heat Affected Zones in Electron Beam Welded ALLVAC® 718PLUS™ Superalloy”, Materials Science and Engineering: A, Vol. 480, pp. 517-528, 2008.
[19].     O. A. Ojo, Y. L. Wang  & M. C. Chaturvedi, “Heat Affected Zone Liquation Cracking in Electron Beam Welded Third Generation Nickel Base Superalloys”, Materials Science & Engineering  A, Vol. 476, pp. 217-223, 2008.
 [20].G. Marchese, X. G. Colera, F.  Calignano, M. Lorusso, S. Biamino, “Characterization and Comparison of Inconel 625 Processed by Selective Laser Melting and Laser Metal Deposition”, Advanced Engineering Material, 2016.

  • Receive Date 30 April 2018
  • Revise Date 13 February 2019
  • Accept Date 27 April 2019