摘要
目的研究匙孔效应在不同激光功率、扫描速度和送粉速率工艺参数下,对熔覆层横截面形貌的影响规律,并揭示匙孔对基体的作用机制。方法利用光束模式为高斯光束分布的YLS-3000光纤激光器进行熔覆镍基高温合金Ni35实验。利用光学显微镜(OM)采集熔覆层横截面宏观形貌,并用金相分析软件以及计算机辅助绘图软件对熔覆横截面参数进行测量。结果随激光功率的增加,匙孔深度增加;随送粉速率和激光扫描速度的增加,匙孔深度减小。随送粉速率的增加和激光功率的减小,熔覆层横截面左右垂直段高度值(H2和H4)减小;随扫描速度的增加,H2和H4先增加再减小。在激光熔覆过程中,当基体没有形成匙孔时,H2和H4的值为零,熔覆层与基体混合区域的横截面形貌为月牙形;当在基体中形成匙孔时,H2和H4的值大于零,熔覆层与基体混合区域的横截面形貌为蘑菇形。结论在激光熔覆过程中,不同激光功率、扫描速度和送粉速率工艺参数对匙孔的影响机制不同。匙孔效应的强弱显著影响熔覆层横截面参数H2和H4的大小,进而影响熔覆层形貌。
The work aims to study the influence of keyhole effect on the cross-section morphology of cladding layer and to reveal the mechanism of keyhole on substrate under different process parameters such as laser power,scanning speed and powder feeding rate.The YLS-3000 fiber laser with Gaussian beam distribution was used to coat Ni-based superalloy Ni35.The cross-section macroscopic morphology of the cladding layer was collected by optical microscope(OM),and the cladding cross-section parameters were measured by metallographic analysis software and computer aided drawing software.With the increase of laser power,the keyhole depth increased.As the scanning speed and the powder feeding rate increased,the keyhole depth decreased.With the increase of powder feeding rate or the decrease of laser power,the height(H2 and H4)of the left and right vertical section of the cladding layer cross section decreased.As the scanning speed increased,H2 and H4 firstly increased and then decreased.During laser cladding,when keyhole was not formed on substrate,H2 and H4 were zero and the cross-sectional shape of the mixed layer of the cladding layer and the substrate was crescent-shaped.When keyhole was formed on the substrate,H2 and H4 were more than zero and the cross-sectional shape of the mixed layer of the cladding layer and the substrate was mushroom-shaped.During laser cladding,different process parameters,laser power,scanning speed and powder feeding rate have different effects on keyhole and the cross-section parameters H2 and H4 of the cladding layer are significantly affected by the strength of the keyhole effect,thus changing the morphology of the cladding layers.
作者
徐平
江国业
胡艳娇
庞铭
XU Ping;JIANG Guo-ye;HU Yan-jiao;PANG Ming(College of Airport Engineering,Civil Aviation University of China,Tianjin 300300,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第10期125-130,共6页
Surface Technology
基金
国家重点研发计划(2018YFB1105800)
中央高校基本科研业务费项目中国民航大学专项资助(3122018D020)
中国民航大学蓝天青年科研资金资助~~
关键词
激光熔覆
匙孔
横截面形貌
高斯光束分布
镍基高温合金
月牙形
蘑菇形
laser cladding
keyhole
cross-sectional morphology
Gaussian beam distribution
nickel-based superalloy
crescent-shaped
mushroom-shaped
