摘要
目的研究石墨烯(Gr)含量对镍基熔覆层组织和性能的影响,通过分析Gr含量对复合熔覆层的影响规律来确定Gr的最佳添加含量,同时进行横向、纵向等2个方向上的摩擦磨损测试,以分析扫描方向对摩擦磨损性能的影响。方法采用预置粉末法制备石墨烯/镍基(Gr/Ni60)合金熔覆层,并针对Gr的质量分数分别为0%、0.3%、0.5%、0.8%、1%的复合涂层进行物相检测、微观组织、显微硬度、摩擦性能等方面的分析。结果Gr的加入没有引起镍基熔覆层相组成的变化,主要组成相为γ−Ni、Cr7C3、Cr23C6。随着Gr含量的增加,复合涂层晶粒尺寸逐渐减小,晶粒明显细化,显微硬度由623.12HV逐步提升到828.65HV,横向磨损平均摩擦因数从0.65降至0.48,磨损率从7.5×10^(−5) mm^(3)/(N·m)降至3.6×10^(−5) mm^(3)/(N·m)。纵向磨损平均摩擦因数从0.70降至0.58,磨损率从5.7×10^(−5) mm^(3)/(N·m)降至4.5×10^(−5) mm^(3)/(N·m)。当Gr的质量分数为1%时复合涂层的晶粒尺寸与Gr的质量分数为0.8%时相比有所增加,且硬度和摩擦性能略有下降。当Gr的质量分数为0.8%时,复合涂层具有更好的晶粒结构、显微硬度和耐磨性,且横向摩擦性能优于纵向摩擦性能。结论在镍基熔覆层中添加Gr可以起到明显的强化作用,过量添加Gr会使熔覆层的显微硬度和摩擦性能下降,在添加Gr之前熔覆层的磨损机制主要为磨粒磨损,加入Gr之后磨损机制转变为黏着磨损和氧化磨损,并伴随磨粒磨损。
The work aims to study the effect of graphene(Gr)content on the microstructure and properties of Ni based laser cladding,and therefore determine the optimal Gr content.Besides,the work analyzes the influence of the scanning direction on the friction and wear properties by conducting friction and wear tests in transverse and longitudinal directions.Graphene Ni-based composite(Gr/Ni60)coatings were prepared by preset powder method with such GrGr mass fractions as 0%,0.3%,0.5%,0.8%and 1%,and therefore such aspects as phase detection,microstructure,microhardness,and friction properties were analyzed.The results showed that the addition of graphene did not transform the phase components of the Ni-based cladding,which mainly includeγ-Ni,Cr_(7)C_(3),and Cr_(23)C_(6).With the raise of Gr content,the grain size of the composite coating decreased,that is,the grain is obviously refined,the microhardness increased gradually from 623.12HV to 828.65HV,the average friction coefficient of transverse wear decreased from 0.65 to 0.48,and the transverse wear rate decreased from 7.5×10^(−5) mm^(3)/(N·m)to 3.6×10^(−5) mm^(3)/(N·m).Meanwhile,the average friction coefficient of longitudinal wear decreased from 0.70 to 0.58 and the longitudinal wear rate decreased from 5.7×10^(−5) mm^(3)/N·m to 4.5×10^(−5) mm^(3)/(N·m).When the Gr content was 1wt.%,the grain size of the composite coating was larger than that of 0.8wt.%,and the microhardness and tribology properties decreased slightly.When the Gr content was 0.8wt.%,the composite coating had more excellent grain structure,microhardness and tribology properties.At the same time,the transverse tribology properties were better than longitudinal tribology properties.The addition of graphene in the Ni based cladding plays a very good strengthening role,but excessive addition of graphene will reduce the micro-hardness and tribology properties of the cladding.Besides,the wear mechanism of the cladding before adding graphene is mainly abrasive wear.After adding graphene,it changes to adhesive wear and oxidative wear simultaneously accompanied by abrasive wear.
作者
单嘉禄
乌日开西·艾依提
SHAN Jia-lu;AIYITI Wurikaixi(College of Mechanical Engineering,Xinjiang University,Urumqi 830017,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第7期420-429,共10页
Surface Technology
基金
新疆维吾尔自治区天山青年计划(2017Q015)。
作者简介
单嘉禄(1997-),男,硕士,主要研究方向为激光熔覆技术;通讯作者:乌日开西·艾依提(1972-),男,博士,教授,主要研究方向为增材制造技术。
