| XU Xiaowen,BIAN Hongyou,LIU Weijun,XING Fei,WANG Wei.Microstructure and Properties of Tribaloy T-800/WC Composite Coating Deposited on DZ125 Directionally Solidified Superalloy by Laser Melting Deposition[J],53(21):162-175 |
| Microstructure and Properties of Tribaloy T-800/WC Composite Coating Deposited on DZ125 Directionally Solidified Superalloy by Laser Melting Deposition |
| Received:April 16, 2024 Revised:July 05, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.21.017 |
| KeyWord:DZ125 alloy T-800 alloy composite coating microstructure laser melting deposition |
| Author | Institution |
| XU Xiaowen |
School of Mechanical Engineering, Shenyang University of Technology, Shenyang , China |
| BIAN Hongyou |
School of Mechanical Engineering, Shenyang University of Technology, Shenyang , China |
| LIU Weijun |
School of Mechanical Engineering, Shenyang University of Technology, Shenyang , China |
| XING Fei |
School of Mechanical Engineering, Shenyang University of Technology, Shenyang , China |
| WANG Wei |
School of Mechanical Engineering, Shenyang University of Technology, Shenyang , China |
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| Abstract: |
| DZ125 directionally solidified superalloy has been widely used in the manufacture of components such as turbine blades for aircraft engines due to its excellent high temperature performance and superior thermal fatigue properties. However, as the DZ125 directionally solidified superalloy turbine blade is operated under high temperature and high pressure for a long period of time, friction and wear will lead to damage and failure of the serrated crown of the turbine blade, resulting in reduced the turbine blade life and reliability. Therefore, the application of surface modification technology to improve the surface wear resistance of the serrated crown is important to extend the service life of turbine blades. Under this engineering background, T-800 alloy coatings and T-800/WC composite coatings were deposited on the surface of DZ125 directionally solidified superalloy by laser cladding, and the macroscopic morphology, phase composition, microstructure, microhardness and the wear properties of the coatings were investigated. The powders selected for laser cladding on the surface of DZ125 directionally solidified superalloy were T-800 alloy powders and T-800/WC composite powders, and the content of WC was 5 wt.%. The substrate for the laser cladding experiment was the DZ125 directionally solidified superalloy with dimensions of 14 mm × 10 mm × 3 mm. The T-800 alloy coating and the T-800/WC composite coating were produced on the DZ125 directionally solidified superalloy through an LDM4030 synchronous laser powder deposition system. The experimental results showed that there were no cracks, pores and other defects in either the T-800 alloy coating or the T-800/WC composite coating. Both coatings formed a good bond to the substrate. The height of the T-800/WC composite coating increased and the dilution rate decreased compared with the T-800 alloy coating. The phases of the T-800 alloy coating were composed of the face-centred cubic Co phase and the Laves phase (Co3Mo2Si). After the addition of WC, additional WC phase, W2C phase and Co6Mo6C phase appeared in the T-800/WC composite coating. The microstructure of the T-800 alloy coating and the T-800/WC composite coating consisted mainly of planar crystal, "flower-like" Laves phase, coarse Laves phase and eutectic structure. Compared with the T-800 alloy coating, the T-800/WC composite coating showed a significant increase in the content of the Laves phase and a decrease in the content of the eutectic structure. The average microhardness and coefficient of friction of the T-800 alloy coating were 630HV0.5 and 0.42, respectively. And the addition of WC improved the coating performance. The average microhardness and coefficient of friction of the T-800/WC composite coating were 697HV0.5 and 0.37, respectively. With the addition of WC, the wear mechanism of the T-800 alloy coating was changed from abrasive wear, adhesive wear and oxidative wear to abrasive wear, fatigue wear and oxidative wear. It is concluded that the microhardness and wear resistance of T-800/WC composite coatings are higher than those of T-800 alloy coatings. The addition of WC promotes grain refinement and precipitation of the Laves phase (Co3Mo2Si) of the coating, resulting in improved microhardness and wear resistance of the coating. |
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