| ZHAN Si-wei,TANG Jun-hui,WANG Feng-tao,JI Xiu-lin.Tribological Behavior of Laser Clad TiZrHfCrMoW High-entropy Alloy Coating in Air and in Simulated Body Solution[J],52(1):29-37 |
| Tribological Behavior of Laser Clad TiZrHfCrMoW High-entropy Alloy Coating in Air and in Simulated Body Solution |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.01.003 |
| KeyWord:laser cladding high entropy alloy friction and wear tribocorrosion simulated body fluid |
| Author | Institution |
| ZHAN Si-wei |
College of Engineering, Shantou University, Guangdong Shantou , China |
| TANG Jun-hui |
Hangzhou Wiseking Surgical Robot Co., Ltd., Hangzhou , China |
| WANG Feng-tao |
College of Engineering, Shantou University, Guangdong Shantou , China |
| JI Xiu-lin |
College of Engineering, Shantou University, Guangdong Shantou , China |
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| Abstract: |
| To improve the wear and corrosion resistance of TC4 titanium alloy, TiZrHfCrMoW high-entropy alloy (HEA) coating was prepared on the surface of TC4 stainless steel by laser cladding, and the tribological behavior of the HEA coating were investigated in air and in 0.9% NaCl solution at (37±0.5) ℃. The microstructure, hardness, COF and OCP curves of HEAs coating and TC4 were measured by experiments. Explore the effect of friction coefficient, hardness and microstructure on the surface fretting wear performance after laser cladding. The microstructure of the HEA coating is uniform, compact, and no defects. It is mainly composed by two body-centered cubic (BCC) solid solution phases and an unknown phase. The average hardness of the HEA coating is around 584.6HV0.2, which is about 1.6 times of the hardness of the substrate TC4. When sliding in the air, the wear rate of the HEA coating was lower than that of the TC4 substrate at 0.3 N, 0.5 N and 1 N. Accordingly, the wear rates are lower over 31 times, 10 times and 1 time than those of TC4 at 0.3 N, 0.5 N and 1 N, respectively. Moreover, the wear rate of the HEA coating increased with the increase of the load, while the wear rate of TC4 was opposite. In 0.9% NaCl solution at (37±0.5) ℃, the wear rate of TC4 under 0.5 N load was 6 times higher than that of HEA coating. Compared with TC4 titanium alloy substrate, HEA coating has higher self-corrosion potential and lower corrosion current density. The main wear mechanism of the HEA coating in the simulated body fluid environment is layer-by-layer exfoliation and corrosion wear. Compared to TC4 alloy, the HEA coating exhibits a high coefficient of friction and low wear rate in both air and 0.9% NaCl solution at (37±0.5) ℃. This is due to the higher hardness of the HEA coating, which increases the resistance of the surface to plastic deformation and the wear resistance, but the coefficient of friction of the HEA coating is slightly higher than that of the TC4 substrate under experimental loading, indicating a different surface contact state. Worn morphologies of HEAs coating in air and 0.9% NaCl solution at (37±0.5) ℃ have some similarities. The main difference is the higher proportion of abrasive wear at higher loads (1 N) in air. In 0.9% NaCl solution, the main wear mechanisms of the HEA coatings are layer-by-layer spalling and corrosive wear. The coating had a higher self-corrosion potential and a lower corrosion current density than the TC4 titanium alloy substrate. Electrochemical test showed that the passive film in the wear track area was only partially destroyed during the corrosive wear test and the corrosion product film affects friction coefficient. In conclusion, laser clad HEA coating can effectively improve the wear resistance and corrosion resistance of TC4 alloy. This work not only provides new ideas and methods for surface modification of TC4, but also shows the advantage of TiZrHfCrMoW coating applied in corrosive wear environment. |
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