| ZHANG Xian,HU Ji,SUI Xin-meng,MA Xin-ran,ZHANG Wei-ping.Effects of Chromium Element Content on Microstructures and Properties of Laser Cladding Ni-Al Coating on TC21 Titanium Alloy[J],49(1):311-317 |
| Effects of Chromium Element Content on Microstructures and Properties of Laser Cladding Ni-Al Coating on TC21 Titanium Alloy |
| Received:May 10, 2019 Revised:January 20, 2020 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2020.01.037 |
| KeyWord:laser cladding titanium alloy Ni-Al Coating Cr element cladding layer microstructure microhardness wear resistance |
| Author | Institution |
| ZHANG Xian |
School of Materials Science and Engineering, Dalian University of Technology, Dalian , China |
| HU Ji |
School of Materials Science and Engineering, Dalian University of Technology, Dalian , China |
| SUI Xin-meng |
School of Materials Science and Engineering, Dalian University of Technology, Dalian , China |
| MA Xin-ran |
School of Materials Science and Engineering, Dalian University of Technology, Dalian , China |
| ZHANG Wei-ping |
School of Materials Science and Engineering, Dalian University of Technology, Dalian , China |
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| Abstract: |
| The work aims to study the effects of chromium (Cr) element content on the microstructures and properties of laser cladding Ni-Al coating on TC21 titanium alloy to improve the surface properties. The Ni-Al coatings with different Cr contents were prepared on the surface of TC21 by laser cladding. The microstructures and phases of cladding layer were analyzed with scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffractometry (XRD). The microhardness distribution and wear resistance were tested with microhardness tester and multifunctional material surface performance tester, respectively. The results showed that the surface quality of cladding layer was good. The main phases of the cladding layer were Ni(Al,Ti), Ni2AlTi and TiNi when there was no Cr element. However, α-Cr precipitation phase appeared after the Cr element was added into the cladding layer, and the relative content of TiNi, Ni2AlTi, α-Cr increased gradually with the increase of Cr content. The microstructure of cladding layer was mainly composed of Ni(Al,Ti) dendritic structure and its surrounding reticular intergranular structure of TiNi, Ni2AlTi and α-Cr. The microhardness of the cladding layers increased to about 2 times of the substrate. Although the Cr content had little effect on improving the microhardness of the Ni-Al coating, it was able to reduce the microhardness fluctuation of the cladding layer to stable. The toughness of the cladding layer was improved with the increase of Cr content. When 20% atomic percentage of Cr was added into the cladding layer, the wear resistance was the best, about 2.948 times than that of the substrate. It reveals that Cr element contributes to the precipitation of α-Cr phase and the generation of TiNi/Ni2AlTi eutectic structure. It effectively reduces the room temperature brittleness, and improves the toughness and wear resistance of the cladding layer. |
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