Inconel 718合金激光熔覆Stellite3/Ti_(3)SiC_(2)复合涂层摩擦学性能研究

Investigation on Tribological Properties of Stellite3/Ti_(3)SiC_(2)Composite Coatings on Inconel 718 Alloy by Laser Cladding

为了探究高温下Inconel 718合金的摩擦学性能,使用激光熔覆制备了三种不同粉末质量配比的复合涂层:Stellite3-5%Ti_(3)SiC_(2)(C1)、Stellite3-10%Ti_(3)SiC_(2)(C2)和Stellite3-15%Ti_(3)SiC_(2)(C3)(均为质量分数),并通过物相分析、组织形貌和显微硬度分析,探究其在室温和600℃条件下的摩擦学行为.结果表明,涂层中主要含有γ-Co、(Fe,Ni)固溶体,金属间化合物Cr_(2)Ni_(3)以及碳化物WCx、TiC和Cr_(7)C_(3),由于硬质相碳化物的存在,涂层的显微硬度提高到基体(262.7 HV_(0.5))的1.6~2.5倍,分别为662.74 HV_(0.5)、521.47 HV_(0.5)和419.44 HV_(0.5),并且摩擦学性能也有所改善,其中室温下效果最好的为C1涂层,摩擦系数降低了20.52%,耐磨性提高了85.45%;600℃下性能最好的为C2涂层,耐磨性提高了79.53%.室温时基体、C1及C2涂层出现塑性变形和磨粒磨损,C3涂层由于硬度较低出现黏着磨损.600℃下各样品均发生氧化磨损,其中氧化、黏着磨损和严重塑性变形为基体的磨损机理,三种涂层由于加入了Ti_(3)SiC_(2)导致磨损减轻,除氧化外主要为磨粒磨损.

Inconel 718 is a nickel-based superalloy which is widely used in various industrial field to manufacture industrial parts,such as aviation on the engine,sheet metal welding parts and so on.Because of the long-term service in harsh working conditions such as high temperature and high pressure,alloy structural parts often fail due to wear,fatigue and other reasons,resulting in the reduced service life.The production cost will increase if it is directly scrapped,so it is of great significance to improve the tribological properties of Inconel 718 alloy at high temperature.Therefore,three kind of composite coatings,Stellite3−5%Ti_(3)SiC_(2)(C1),Stellite3-10%Ti_(3)SiC_(2)(C2)and Stellite3-15%Ti_(3)SiC_(2)(C3)(mass fraction)were prepared on the surface by laser cladding.The tribological behavior at room temperature and 600℃was investigated by phase analysis,microstructure and microhardness analysis.The phase analysis results showed that the coating mainly containsγ-Co,(Fe,Ni)solid solution,intermetallic compound Cr_(2)Ni_(3)and carbides WCx,TiC and Cr_(7)C_(3).And due to the existence of these hard phase carbides,the microhardness of the coating increased to 1.6~2.5 times than that of the matrix(262.7 HV_(0.5)),which were 662.74 HV_(0.5),521.47 HV_(0.5)and 419.44 HV_(0.5),respectively.The tribological properties of the three coatings had also been improved,and C1 coating had the best property at room temperature among them,for its friction coefficient was reduced by 20.52%and its wear resistance was increased by 85.45%;the wear resistance of C2 coating at 600℃increased by 79.53%.At room temperature,the wear mechanisms of the substrate,C1 and C2 coatings were mainly plastic deformation and abrasive wear,while the C3 coating appeared adhesive wear because of the decrease of hardness.All samples were oxidized at 600℃,and the substrate showed severe plastic deformation and adhesive wear.The wear of the three coatings was reduced due to the addition of Ti_(3)SiC_(2),which were mainly oxidative wear and abrasive wear.