| SHEN Jing-yi,LIN Chen,YAO Yong-qiang,XU Huan-huan,LIU Jia.Effect of Ultrasound Vibration on Microstructure and Properties of Laser Cladding Coatings[J],48(12):226-232 |
| Effect of Ultrasound Vibration on Microstructure and Properties of Laser Cladding Coatings |
| Received:July 13, 2019 Revised:December 20, 2019 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2019.12.027 |
| KeyWord:laser cladding ultrasonic vibration nickel-coated WC element distribution microhardness wear resistance |
| Author | Institution |
| SHEN Jing-yi |
Qingdao University of Technology, Qingdao , China |
| LIN Chen |
Qingdao University of Technology, Qingdao , China |
| YAO Yong-qiang |
Qingdao University of Technology, Qingdao , China |
| XU Huan-huan |
Qingdao University of Technology, Qingdao , China |
| LIU Jia |
Qingdao University of Technology, Qingdao , China |
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| Abstract: |
| The work aims to eliminate the defects such as pore and crack in traditional laser cladding coatings, and improve the overall quality and performance of coatings. Nickel-coated WC alloy powders were pre-placed on Q235 matrix by adhesive and the cladding test was carried out with the optimum parameters obtained through orthogonal test (laser power P=1600 W, spot diameter d=5 mm, scanning speed ν=4 mm/s). During the whole cladding process, a 20 kHz ultrasonic generator was used to synchronously apply ultrasonic vibration to the laser pool with air as the carrier. Then, the microstructure, element composition, phase, microhardness and wear resistance of the coatings were measured and analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), microhardness tester and universal friction and wear tester (UMT). The grains of the dynamic coatings by ultrasonic vibration were finer and mainly consisted of fine equiaxed grains and columnar grains. The pores and cracks in such coatings were obviously reduced. Elements such as Cr, Ni, W, and C tended to be distributed uniformly. The coating was mainly composed of solid solution γ-(Ni,Fe), intermetallic compound Ni3Fe, WC, Cr23C6 and so on. The average microhardness of the coating after application of ultrasonic vibration was 937HV, which was 13% higher than that of the coating not treated by ultrasonic vibration. The coefficient of friction was 0.43, which was reduced by about 26% and the wear resistance was improved by 44%. Laser cladding assisted by air-load ultrasonic vibration can significantly improve the quality of the coatings, make the microstructure more compact, and increase the hardness and wear resistance. |
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