| ZHANG Lian-wang,NIU Wei,SUN Rong-lu,ZUORun-yan,GU Mi,MAShi-zhong.Effect of Heat Treatment on Microstructure and Properties of Laser Cladding CoCrFeNiSi2.0 High Entropy Alloy Coating[J],51(12):340-349 |
| Effect of Heat Treatment on Microstructure and Properties of Laser Cladding CoCrFeNiSi2.0 High Entropy Alloy Coating |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.12.035 |
| KeyWord:heat treatment laser cladding Si high-entropy alloy macromorphology microhardness wear resistance |
| Author | Institution |
| ZHANG Lian-wang |
School of Mechanical Engineering, Tiangong University, Tianjin , China |
| NIU Wei |
School of Mechanical Engineering, Tiangong University, Tianjin , China;Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology, Tianjin , China |
| SUN Rong-lu |
School of Mechanical Engineering, Tiangong University, Tianjin , China;Tianjin Key Laboratory of Advanced Mechatronics Equipment Technology, Tianjin , China |
| ZUORun-yan |
School of Mechanical Engineering, Tiangong University, Tianjin , China |
| GU Mi |
School of Mechanical Engineering, Tiangong University, Tianjin , China |
| MAShi-zhong |
School of Mechanical Engineering, Tiangong University, Tianjin , China |
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| Abstract: |
| It is a relatively novel way to improve the properties of coating by Laser cladding on 45# steel by heat treatment,the properties of the coating were improved by the transformation of microstructure phase composition of the sample after heat treatment at a certain temperature,such as wear resistance microhardness and other properties. Different samples were heated to different temperatures with the same heating method, and kept at different temperatures for the same time, then cooled to room temperature with the furnace. In this process, the degree of coating phase transformation is also different due to the different heating temperature,which just reflects that the improvement degree of coating performance is also different. The wear resistance and microhardness of the coating before and after heat treatment were studied in this article. The 45# steel with dimensions of 50 mm× 50 mm× 7 mm and 25 mm×50 mm×7 mm is prepared by wire cutting as multi-channel and single channel substrate. The surface of the substrate to be coated is grinded by grinding wheel, polished with sandpaper to remove oxide scale, and cleaned with absolute ethanol and acetone to remove surface dirt. CoCrFeNiSi2.0 high entropy alloy coating was prepared by RFL-C1000 laser machine.The high-temperature furnace is heated to different temperatures (600 ℃, 800 ℃ and 1 000 ℃) for 30 minutes, which shall be kept at different temperatures for 30 minutes, and then cooled to room temperature with the furnace. Cut the sample with wire cutting and polish the cross section, and corrode it with Saturated ferric chloride hydrochloric acid etchant. Then, observe the microstructure of the cladding layer by scanning electron microscope (ZEISS Sigma300). The component is analyzed by the EDS spectrum of each selected point taken by an energy spectrometer (ZEISS Sigma300). Analyze the phase composition of the coating by an X-ray diffractometer (Bruker D8) and test the microhardness of the cladding layer by microhardness tester (HV-1000Z).The friction test is performed on a high speed rotating grinding wheel and wear tester (M-2000), Calculate the wear weight and observe the surface morphology after wear. The high entropy alloy coating of the original sample without heat treatment is mainly composed of BCC phase and a small amount of (Fe,Mn)2SiO4 phase. With the increase of annealing temperature, (Fe,Mn)2SiO4 gradually decomposes, Cr2Si, Ni4Si phases are precipitated and the content gradually increases with the temperature rise within a certain temperature range. The height of the diffraction peak of BCC phase increases first and then decreases with the increase of heat treatment temperature. Different heat treatment temperatures will affect the change of overall performance of the coating. The increase of Cr2Si, Ni4Si phase content is the main reason for the performance improvement of coating. When the heat treatment temperature is at 800 ℃, the overall performance of the alloy is better than that of the original sample coating. As a result, The microhardness of the coating is up to 1 347.4HV0.3, and the friction coefficient is basically stable at 0.19. The high entropy alloy coating is annealed at 1 000 ℃, the internal phase composition of high entropy alloy coating is a single BCC phase, which is bound to have a certain impact on the performance of the coating. |
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