| TANG Chen,YU Chengtao,WANG Qunchang,CHEN Minghui,WANG Fuhui.High-temperature Tribological Behavior of Spark Plasma Sintered CoCrW Alloy[J],54(3):80-89 |
| High-temperature Tribological Behavior of Spark Plasma Sintered CoCrW Alloy |
| Received:February 01, 2024 Revised:July 01, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2025.03.006 |
| KeyWord:CoCrW alloy microstructure high temperature tribological properties high temperature oxidation glaze layer spark plasma sintering |
| Author | Institution |
| TANG Chen |
School of Materials Science and Engineering, Northeastern University, Shenyang , China |
| YU Chengtao |
School of Materials Science and Engineering, Northeastern University, Shenyang , China |
| WANG Qunchang |
School of Materials Science and Engineering, Northeastern University, Shenyang , China |
| CHEN Minghui |
School of Materials Science and Engineering, Northeastern University, Shenyang , China |
| WANG Fuhui |
School of Materials Science and Engineering, Northeastern University, Shenyang , China |
|
| Hits: |
| Download times: |
| Abstract: |
| CoCrW alloy (Stellite alloy), as a kind of Co-based wear-resistant alloy, is widely used in turbine engines and other high temperature sliding contact parts due to its low friction coefficient and good wear resistance at high temperature. The high temperature tribological behavior of CoCrW alloy determines the service life, safety and stability of high temperature sliding contact parts. According to the Fe-based, Co-based and Ni-based superalloy, a hard and smooth compacted oxide layer, called glaze layer, is formed on the alloy surface by the synergistic effect of the high-temperature oxidation and tribological behavior, which improves the tribological properties of alloy at high temperature during the wear process. Many studies have indicated that the ambient temperature has a significant impact on the tribological properties of Co-based alloy. As a new powder metallurgy technology, spark plasma sintering (SPS) has the advantages of a fast heating rate, low sintering temperature, and short sintering time. However, there are few studies on the high temperature tribological properties of Co-based alloy prepared by SPS. This work aims to investigate the microstructure and high temperature (400-800 ℃) tribological properties of CoCrW alloy prepared by spark plasma sintering (SPS). The high temperature tribological properties of SPSed CoCrW alloy at 400- 800 ℃ was tested by reciprocating friction and wear machine and the wear rates were measured by white-light interferometer. The microstructure, phase constitution and element distribution of the CoCrW alloy, wear scars and debris, were investigated by SEM, EDS, EBSD, Raman spectra and EPMA. Meanwhile, the formation and evolution mechanism of the glaze layer were clarified. The results indicated that the SPSed CoCrW alloy had uniform microstructure, which consisted of γCo, εCo and Cr7C3. At the same time, Cr7C3 dispersed uniformly inside the matrix of the alloy, played an important role in inhibiting grain growth during sintering. Serious abrasive wear occurred at 400 ℃ on account of insufficient oxide debris for the formation of the glaze layer, with a coefficient of 0.27 and a wear rate of 2.55×10−4 mm3/(N.m). However, at 600 ℃, protective oxide islands were formed locally, which weakened the abrasive wear behavior of the hard debris, with a friction coefficient of 0.43 and a wear rate of 4.03× 10−5 mm3/(N.m). At 800 ℃, a stable glaze layer composed of Cr2O3, CoCr2O4 and Co3O4 was formed on the wear surface of the alloy, and the wear rate decreased by 91% compared with that at 400 ℃, with a friction coefficient of 0.37 and a wear rate of 2.36×10−5 mm3/(N.m). The increase of temperature accelerates the diffusion of ions and the refinement of debris that promotes the sintering of oxide particles on the wear surface and the formation of a glaze layer which prevents the contact between friction pairs. The plastic deformation of the subsurface is impeded by the formation of protective glaze layer at 800 ℃ initial wear stage. Then, the rapid diffusion of metal and oxygen ions facilitate the formation of Cr-rich oxide layer inside and mixed oxide layer on the surface, which makes the glaze layer more stable. |
| Close |
|
|
|