激光能量密度对Al_(2)O_(3)颗粒增强Ni60A激光熔覆涂层组织及性能的影响  

Effect of Laser Energy Density on Microstructure and Properties of Al_(2)O_(3) Particle Reinforced Ni60A Laser Cladding Coating

作　　者：马保山 姜芙林 杨发展 王玉玲 梁鹏 MA Bao-shan;JIANG Fu-lin;YANG Fa-zhan;WANG Yu-ling;LIANG Peng(School of Mechanical and Automotive Engineering,Qingdao University of Technology,Shandong Qingdao 266520,China)

机构地区：[1]青岛理工大学机械与汽车工程学院,山东青岛266520

出　　处：《表面技术》2023年第5期364-377,共14页Surface Technology

基　　金：山东省重点研发计划(2019GNC106102);山东省自然科学基金(ZR2019MEE059,ZR2021ME198);高等学校学科创新引智计划(D21017)。

摘　　要：目的 实现钛合金表面强化和正向改性,扩大钛合金应用范围。方法 采用预置粉末法在钛合金表面制备Ni60A-Al_(2)O_(3)激光熔覆层,通过改变激光功率,进而研究激光能量密度对Ni60A-Al_(2)O_(3)熔覆层横截面形貌、微观组织、元素分布、显微硬度以及耐磨性和耐腐蚀性的影响规律。结果 激光能量密度对熔覆层的平整性、成形性有着直接影响。不同激光能量密度下的熔覆层微观组织相似,但在125 J/mm^(2)下,熔覆层形成的陶瓷增强相分布更均匀,且杂质相衍射峰面积较小,元素分布更均匀。此时,熔覆层的力学性能也最好,平均显微硬度值为1132.7HV0.2,较基体硬度提升约3.3倍,摩擦系数最小,且波动较平稳,磨损率也最低,具有较好的减摩性和耐磨性。125J/mm^(2)下熔覆层形成的陶瓷增强相TiC、TiB_(2)既能作为不良导体降低电化学腐蚀速率,又由于分布均匀而避免应力集中引发裂纹,较其他激光能量密度下的熔覆层具有较好的耐腐蚀性。结论 利用控制变量法探究激光能量密度对Ni60A-Al_(2)O_(3)熔覆层组织和性能的影响规律,得出在125 J/mm^(2)下的熔覆层具备优异的力学性能和一定的耐腐蚀性,为进一步扩大钛合金应用提供了帮助。TiNi alloy is widely used in titanium alloy surface modification because of its excellent toughness,corrosion resistance,biocompatibility,high damping and superelasticity.However,its low hardness often requires the introduction of ceramic reinforced phases to improve mechanical properties.Because of its advantages of heat concentration,fast heating and cooling,small heat affected zone and good controllability,laser cladding technology has greater superiority in the repair of failed parts and the positive modification of strengthened parts.In the laser cladding process,multiple process parameters are coupled together to affect the quality of the cladding coating,and the laser energy density is often selected as the heat input evaluation index.The work aims to study the effect of laser energy density on the microstructure and properties of Al_(2)O_(3) particles reinforced Ni60A composite coatings,so as to realize the surface strengthening and positive modification of titanium alloy and expand the application range of titanium alloy.The TC4 titanium alloy was cut into 70 mm×15 mm×6 mm cuboid specimens by wire cutting,smoothed with sandpaper and ultrasonically cleaned for 30 min.Ni60A-12%Al_(2)O_(3)(quality scores)composite powder balls were ground for 2 h and dried at 120 ℃ for 2 h and then pre-coated on clean and smooth TC4 titanium alloy surface.The test was carried out by a FL 020fiber laser.During the cladding process,the scanning speed was 3 mm/s,the spot diameter was 4 mm,and the laser power was 1 300 W,1 400 W,1 500 W,1 600 W and 1 700 W,respectively.Wire cutting was used to process the cladded workpiece into small specimens of 15 mm×15 mm×6 mm,and the cross section was grounded and corroded with a mixture of HF∶HNO_3∶H_(2)O with a volume ratio of 1∶3∶9.The cross-sectional morphology and microstructure of the cladding coating were then observed and analyzed by MERLIN Compact field emission scanning electron microscopy.An energy spectrometer(EDS)was used to analyze the composition and distributio

关 键 词：激光能量密度 Ni60A-Al_(2)O_(3)涂层 微观组织 元素分布 力学性能 耐腐蚀性 

分 类 号：TG174.4[金属学及工艺—金属表面处理]