表面技术2025，Vol.54Issue(12)：85-96,12.DOI:10.16490/j.cnki.issn.1001-3660.2025.12.007
激光功率对CoCrNiMo0.5Nb0.2熔覆层的组织演变及应力腐蚀性能的影响
Effect of Laser Power on the Microstructure Evolution and Stress-corrosion Properties of CoCrNiMo0.5Nb0.2 Cladding Layer
摘要
Abstract
42CrMo steel is commonly used as load-bearing components in marine equipment,so it has a significant tendency to suffer stress corrosion in the long-term marine service environment.High-entropy alloys are a new type of multi-component alloy that exhibits excellent properties such as high strength,high hardness,wear resistance,resistance to high-temperature oxidation,and corrosion resistance.Laser cladding technology,as a new type of surface modification technology,is one of the ways to prepare high-entropy alloy cladding layer,which is characterized by fast heating speed,high solidification rate,small heat-affected zone and low dilution rate.The work aims to prepare CoCrNiMo0.5Nb0.2 cladding layer on the surface of 42CrMo steel with laser cladding technology under different laser powers,and the surface of the cladding layer prepared under each laser power is relatively flat,which is in line with the requirements of the subsequent test.Firstly,its microstructure and phase composition were observed,and it was determined that the CoCrNiMo0.5Nb0.2 high-entropy alloy fused cladding layers prepared under different laser powers were composed of FCC phases,Laves phases and a small amount of BCC phases,and the layer microstructures all showed eutectic morphology,and the appropriate laser power could promote the formation of eutectic microstructures,in which the eutectic microstructure of the fused cladding layer under the power of 1 100 W was denser.Secondly,the electrochemical test showed the corrosion resistance of the layer and the effect of the laser power on the corrosion resistance.Good eutectic microstructure was to some extent conducive to enhancing the corrosion resistance of the layer.Finally,the stress-corrosion properties were characterized by three-point stress loading immersion experiment and slow strain rate tensile(SSRT)experiment.The corrosion of the layer at three-point stress loading immersion was mainly dominated by pitting corrosion,in which the layer prepared at 1 100 W laser power showed less surface corrosion after the corrosion immersion experiment,and the layer prepared at 1 200 W laser power showed smaller stress corrosion cracks in the immersion period of 21 days-28 days.Under the action of dead load,the layers prepared by different laser powers showed excellent stress-corrosion resistance,and the harmony between the layer and the matrix junction was still good after the dead load immersion test.With the increase of laser power,the stress-corrosion resistance of the layer showed a trend of increasing and then decreasing.The layer prepared at 1 100 W laser power had the lowest stress-corrosion sensitivity of 3.92％.The sensitivity index of the layer prepared at 1 000 W laser power was 8.66％,and the sensitivity index of the layer prepared at 1 200 W laser power was 15.38％.The layers prepared at different laser powers all have less surface corrosion after corrosion immersion and good stress-corrosion resistance.The fracture morphology of the tensile specimens is deconvoluted fracture and quasi-deconvoluted fracture,and the fracture form is brittle fracture.Through the analysis of the above results,it can be seen that the laser power can affect the formation of the eutectic microstructure,thus affecting its corrosion resistance and mechanical properties,further affecting the resistance of the material to stress corrosion,so the layer with a dense and good eutectic microstructure has better resistance to stress corrosion.关键词
激光熔覆/高熵合金/激光功率/共晶组织/应力腐蚀Key words
laser cladding/high-entropy alloy/laser power/eutectic microstructure/stress corrosion分类
矿业与冶金引用本文复制引用
宋涛,姜芙林,魏长生,张耀辉,杨发展,梁鹏..激光功率对CoCrNiMo0.5Nb0.2熔覆层的组织演变及应力腐蚀性能的影响[J].表面技术,2025,54(12):85-96,12.基金项目
山东省自然科学基金资助项目(ZR2022MEE081,ZR2021ME198) （ZR2022MEE081,ZR2021ME198）
山东省主要农作物机械化生产装备协同创新中心开放课题项目(SDXTZX-21) （SDXTZX-21）
高等学校学科创新引智计划资助(D21017)Shandong Provincial Natural Science Foundation under Grant(ZR2022MEE081,ZR2021ME198) （D21017）
Collaborative Innovation Center for Shandong's Main Crop Production Equipment and Mechanization(SDXTZX-21) （SDXTZX-21）
111 project(D21017) （D21017）
