激光能量密度对CrFeCoNiNb熔覆层组织演变和性能影响的试验研究  

Experimental Study on the Effect of Energy Density on Microstructure Evolution and Properties of CrFeCoNiNb Cladding Layer

作　　者：宋鹏芳 姜芙林 王玉玲[1] 杨发展[1] 王冉[1] SONG Pengfang;JIANG Fulin;WANG Yuling;YANG Fazhan;WANG Ran(Key Laboratory of Laser Green Intelligent Manufacturing Technology,Qingdao University of Technology,Qingdao 266520;Key Laboratory of High-efficiency Clean Machinery Manufacturing Ministry of Education,Shandong University,Jinan 250061)

机构地区：[1]青岛理工大学激光绿色智能制造技术重点实验室,青岛266520 [2]山东大学高效洁净机械制造教育部重点实验室,济南250061

出　　处：《机械工程学报》2023年第2期127-137,共11页Journal of Mechanical Engineering

基　　金：山东省重点研发计划(2019GNC106102);山东省自然科学基金(ZR2018PEE011,ZR2019MEE059)资助项目。

摘　　要：采用预置粉末法在42CrMo基体表面制备CrFeCoNiNb高熵合金激光熔覆层,探索激光能量密度对CrFeCoNiNb熔覆层组织和性能的影响规律。对于预置粉末激光熔覆工艺,激光功率、扫描速度、光斑直径作为工艺参数三要素,不是独立影响熔覆层质量与性能,且激光功率对熔覆层质量与性能的影响最大。通过改变激光功率进而改变作用于熔覆层的激光能量密度,研究激光能量密度对CrFeCoNiNb高熵合金熔覆层硬度、耐磨性和耐腐蚀性的影响规律。试验结果表明:熔覆层主相为面心立方结构相(FCC相)和密排六方结构相(Laves相)。随着激光能量密度的增加,其衍射峰面积先减少后增加,熔覆层晶粒先细化后粗化,转折点处的激光能量密度都为116.7 J/mm2。而且,此时熔覆层物相分布更均匀,磨损形貌主要为光滑的犁沟,相应的减摩效果好,磨损率有所降低。主相含量的改变和晶粒尺寸的改变分别是影响熔覆层平均显微硬度和耐腐蚀性的主要因素。Laves硬质相的增加有利于熔覆层硬度的提高,细化的晶粒可以形成致密的钝化膜,有利于提高熔覆层耐腐蚀性。CrFeCoNiNb high entropy alloy laser cladding layer was prepared on the surface of 42CrMo substrate by powder preseting method, and the effect of laser energy density on the microstructure and properties of CrFeCoNiNb cladding layer was investigated.For the preset powder type, the influence of laser power on the quality of cladding layer is the largest and most intuitive among the three factors of process parameters. For the type of powder preseting method, laser power, scanning speed and spot diameter are three factors of process parameters, which do not independently affect the quality and performance of the cladding layer, and laser power has the greatest influence on the quality and performance of the cladding layer. By changing the laser power and then changing the laser energy density acting on the cladding layer, the influence of the laser energy density on the hardness, wear resistance and corrosion resistance of the high entropy CrFeCoNiNb alloy cladding layer was studied. The experimental results show that with the increase of energy density, the main phase content of the body-centered cubic(BCC) decreases at first and then increases, and the grain of the cladding layer is refined at first and then coarsely. The energy density at the turning point is 116.7 J/mm~2. Moreover, at the point, the phase distribution of the cladding layer is more uniform, and the wear morphology is mainly smooth furrow. The corresponding friction reduction effect is good, and the wear rate is reduced to a certain extent. The change of the content of main phase and the change of grain size correspond to the main factors which affect the average microhardness and corrosion resistance of cladding layer respectively. The increase of BCC phase is beneficial to the improvement of the hardness of the cladding layer, and the refined grain can form a dense passivation film, which is beneficial to the improvement of the corrosion resistance of the cladding layer.

关 键 词：激光能量密度 高熵合金 显微组织 力学性能 耐腐蚀性 

分 类 号：TG133[一般工业技术—材料科学与工程]