| JIA Yan-jun,CHEN Han-ning,ZHANG Jia-qi,LEI Jian-bo.Research on Wear Resistance and Electrochemical Corrosion Properties of CoCrNiNbW High Entropy Alloy by Laser Melting Deposited[J],51(12):350-357, 370 |
| Research on Wear Resistance and Electrochemical Corrosion Properties of CoCrNiNbW High Entropy Alloy by Laser Melting Deposited |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.12.036 |
| KeyWord:laser melting deposition additive manufacturing high-entropy alloys wear resistance electrochemical corrosion performance |
| Author | Institution |
| JIA Yan-jun |
School of Mechanical Engineering, Tianjin , China |
| CHEN Han-ning |
School of Computer Science and Technology Tiangong University,Tianjin , China |
| ZHANG Jia-qi |
Laser Technology Institute, Tiangong University,Tianjin , China |
| LEI Jian-bo |
Laser Technology Institute, Tiangong University,Tianjin , China |
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| Abstract: |
| The service life of Q235 steel is shortened due to wear and corrosion in practical application. It is necessary to improve the microhardness, wear resistance and corrosion resistance of Q235 steel surface. High entropy alloy (HEA) is a new type of high strength alloy with relatively uniform microstructure distribution and ideal mechanical properties and stable structure. Due to the characteristics of high hardness, good high temperature performance, excellent corrosion resistance and oxidation resistance, HEA is widely used in machinery manufacturing, aerospace, green processing surface engineering and other important fields which have great development potential and broad application prospects. A crack-free CoCrNiNbW high-entropy alloy coating was fabricated on the surface of Q235 steel by laser melting deposition technology in this artical. The substrate is Q235 steel. The surface is cleaned by laser cleaning machine (Shandong Haifu photon HFB-C50) to remove impurities on the substrate surface and prevent metal oxides and impurities from affecting the experimental effect.Apply the Laserline-4000 laser in the CoCrNiNbW cladding experiment. The optimum process parameters were determined after optimization. The moving speed of the spot is 8 mm/s during the cladding process; the laser power of the multi-pass cladding is 720 W, and the overlap between the two adjacent passes is 50%.The phase was analyzed by X-ray diffractometer (XRD) (Japanese science D / max-2500) (Cu target, acceleration voltage 40 kV, working current 140 mA). Optical microscope (Leica dvm6a), scanning electron microscope (Zeiss sigma 300) and X-ray spectrometer were used (EDS), accelerating voltage 15 kV). The macro morphology, microstructure morphology, composition and distribution of elements of the samples were observed. The dry sliding friction test of the coating was carried out by M-2000 friction and wear tester at room temperature. The material of the grinding ring is GCr15, the load is set to 120 N, and the wear time is 1 hour. After the wear experiment, collect the wear debris, observe the morphology of wear marks and wear debris, and analyze the wear type and wear resistance of the material. The electrochemical workstation (CHI-640) test was used to analyze the electrochemical corrosion behavior of the high-entropy alloy coating and Q235 steel. The electrochemical impedance spectroscopy, self corrosion potential and corrosion current density were analyzed by software, the electrochemical evaluation parameters of the samples were obtained, and the corresponding equivalent circuit was established. The microstructure of the CoCrNiNbW high-entropy alloy coating is mainly composed of equiaxed crystals, and there are unmelted Nb and W particles in the middle and bottom of the coating, which play the role of strengthening phase; The main phases are composed of the FCC phase rich in Co, Ni and the BCC phase rich in Nb. The average microhardness of the high-entropy alloy coating is 800HV0.2, which is about four times that of the substrate material. The wear mechanism is mainly abrasive wear, and the wear rate is 2.315×10–5 g.m–1, which is about 1/5 of the substrate material. In 3.5 wt.% NaCl solution, high-entropy alloy coating has better corrosion resistance, and the corrosion resistance is about 8 times that of the substrate. The microhardness, wear resistance, and corrosion resistance of the high-entropy alloy coating are greatly improved compared to the Q235 steel substrate. |
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