Improved mechanical properties of Ni-rich Ni3Al coatings produced by EB-PVD for repairing single crystal blades

• Published in: Rare metals Vol. 36; no. 7; pp. 556 - 561
• Main Authors: Sun, Jing-Yong, Pei, Yan-Ling, Li, Shu-Suo, Zhang, Hu, Gong, Sheng-Kai
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 01.07.2017; Springer Nature B.V
• Subjects: Active control; Aerospace engines; Aluminum coatings; Al涂层; Biomaterials; Blade tips; Chemistry and Materials Science; Coating effects; EB-PVD; Electron-beam physical vapor deposition; Energy; Grain size; Intermetallic compounds; Materials Engineering; Materials Science; Mechanical properties; Metallic Materials; Microhardness; Microstructure; Nanoscale Science and Technology; Ni3Al; Nickel; Nickel aluminides; Physical Chemistry; Single crystals; Tip clearance; Turbine blades; Zirconium; 修复效果; 单晶叶片; 机械性能; 电子束物理气相沉积; 航空发动机; Heat treatment; Electron beam physical vapor deposition; Repair coating; Ni; Al; Blades tips; Single crystal
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-014-0340-1

Active control of turbine blade tip clearance for aircraft engine continues to be a concern in engine opera- tion, because turbine blades are subjected to wear and therefore cause an increasing tip clearance between the rotating blades and the shroud and also reduce the engine efficiency. In this work, a Ni-rich Ni3A1 coating with γ＇/γ two-phase microstructure was deposited by electron beam physical vapor deposition （EB-PVD）, which worked as repairing the worn blade tips of single crystal blades. Nb molten pool was used to increase the molten pool tem- perature and thus to enhance the deposition rate. The microstructures and mechanical properties can be modified by the deposition temperatures and the following heat treatments. All coatings consist of γ＇ and γ phases. At deposition temperature of 600 ℃, a dense microstructure can be achieved to produce a coating with grain size of 1 μm and microhardness of -HV 477. After being heated for 4 h at a temperature of 1,100 ℃, the coatings have a more uniform microstructure, and microhardness maintains at a high level of -HV 292. Effect of Hf and Zr on EB-PVD Ni3Al repair coating will be further investigated.