| LI Fang-zhou,CUI Gong-jun,CHENG Shu-shuai,WANG Xiao-bo,KOU Zi-ming.Effects of MoSi2 on Friction and Wear Properties of CoCrNiW Alloy under Dry-sliding Condition[J],52(1):82-92 |
| Effects of MoSi2 on Friction and Wear Properties of CoCrNiW Alloy under Dry-sliding Condition |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.01.009 |
| KeyWord:Co matrix composite MoSi2 dry-sliding friction and wear wear mechanism |
| Author | Institution |
| LI Fang-zhou |
College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan , China;Shanxi Mine Fluid Control Engineering Laboratory, Taiyuan, China;National-local Joint Engineering Laboratory of Mine Fluid Control, Taiyuan , China |
| CUI Gong-jun |
College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan , China;Shanxi Mine Fluid Control Engineering Laboratory, Taiyuan, China;National-local Joint Engineering Laboratory of Mine Fluid Control, Taiyuan , China |
| CHENG Shu-shuai |
College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan , China;Shanxi Mine Fluid Control Engineering Laboratory, Taiyuan, China;National-local Joint Engineering Laboratory of Mine Fluid Control, Taiyuan , China |
| WANG Xiao-bo |
College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan , China;Shanxi Mine Fluid Control Engineering Laboratory, Taiyuan, China;National-local Joint Engineering Laboratory of Mine Fluid Control, Taiyuan , China |
| KOU Zi-ming |
College of Mechanical and Vehicle Engineering, Taiyuan University of Technology, Taiyuan , China;Shanxi Mine Fluid Control Engineering Laboratory, Taiyuan, China;National-local Joint Engineering Laboratory of Mine Fluid Control, Taiyuan , China |
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| Abstract: |
| The work aims to design the wear resistant CoCrNiW matrix composites, and the effect of MoSi2 on the friction and wear properties of CoCrNiW alloys under dry-sliding condition, to develop CoCrNiW-based composites of excellent tribology performance. The wear resistant CoCrNiW-MoSi2 (0 wt.%, 3 wt.%, 7 wt.%, 11 wt.%) composites were fabricated with the powder metallurgy technology. The effects of load and sliding speed on the tribological properties of composites were studied under dry-sliding condition with a reciprocating ball-on-disk tribo-tester, and the MoSi2 content was further optimized. The phase composition, microstructure and wear morphology of materials were analyzed by XRD, SEM and EDS. During the sintering process, the high-temperature solid solution reaction occurred at the interface of MoSi2 and metal matrix. The composites consisted of γ-fcc, ε-hcp, MoSi2, CrSi2, Mo1.24Ni0.76 and MoSi2.43W0.211 phases. The microstructure of composite was dense, and no hole was noted on the surfaces. The addition of MoSi2 effectively improved the hardness and compactness of materials as well as the stability of γ-fcc phase. The friction coefficients decreased with the increase of load. This was caused by the fact that the increasing rate of load was faster than that of the actual contacting area of the tribo-pairs. The friction coefficients of composites with sliding speed showed the similar trend, resulting from the decrease in hardness of worn surfaces due to the friction heat. The reasonable MoSi2 content played an important part in decreasing the friction coefficient of composites. The sample with 7wt.% MoSi2 had the lowest friction coefficients as compared with other samples. The friction coefficients of CoCrNiW-7wt.% MoSi2 were in the range of 0.24-0.53, which were significantly lower than those of unreinforced sample. The effect of sliding speed and load on the wear rates of composites was different. The wear rates increased with the increase of load, and decreased with the increase of sliding speed. The hard silicide particles had the dispersion strengthening effect and improved the loading capacity of the worn surface. The samples with 7 wt.% and 11 wt.% MoSi2 had the low wear rates, and the wear rate was 31.3% lower than that of unreinforced composites at 20 N and 0.15 m/s. Meanwhile, the wear rate was 25.5% lower than that of the sample without MoSi2 at 40 N and 0.083 m/s. CoCrNiW-7 wt.% MoSi2 showed the best tribological properties, and the wear rates were in the range of 4.98×10–6-9.41×10–6 mm3.N–1.m–1. It was attributed to the high loading capacity and the tribo-layer containing oxides on the worn surface. For the sample containing 7 wt.% MoSi2, the oxides content on the worn surface was high at high sliding speed. The tribo-layers formed by the oxides prevented the contacting surface from wear. In addition, it was observed that the size of wear debris decreased when the load increased from 20 N to 40 N. At 20 N and 0.15 m/s, an incomplete transferred layer was noted on the worn surface of steel ball which could reduce the direct contacting area of tribo-pairs during the friction process. CoCrNiW-7 wt.% MoSi2 show the best tribological properties. The main wear mechanism is abrasive wear at high load. The abrasive wear and slight oxidative wear are the main wear mechanism at high sliding speed. |
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