圆环摆动激光沉积碳化钨增强镍铜合金微观组织及耐磨性研究  

Microstructure and Wear Resistance of Tungsten-Carbide-Reinforced Nickel Copper Alloy Deposited by Circular Oscillating Laser

作　　者：陈思宇 夏椰林 刘兴宇 雷剑波[2] 王涛[1] Chen Siyu;Xia Yelin;Liu Xingyu;Lei Jianbo;Wang Tao(College of Aeronautical Engineering,Civil Aviation University of China,Tianjin 300300,China;Laser Technology Institute,Tiangong University,Tianjin 300387,China)

机构地区：[1]中国民航大学航空工程学院,天津300300 [2]天津工业大学激光技术研究所,天津300387

出　　处：《中国激光》2023年第20期37-47,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金民航联合基金重点项目(U2233201)。

摘　　要：为提升NiCu合金的硬度,改善其耐磨性,采用圆环摆动激光定向能沉积了NiCu和掺有30%(质量分数)WC的NiCu(NiCu/30%WC)复合材料。研究了圆环摆动激光和WC颗粒对NiCu合金的物相成分、微观组织、显微硬度和摩擦磨损性能的影响规律和强化机制。圆环摆动激光的搅拌作用增强了熔池对流,使WC颗粒在沉积层中均匀分布,减少了柱状枝晶的生成;同时WC颗粒及其分解后形成的碳化物阻碍晶粒生长,促进了沉积层晶粒的细化。NiCu/30%WC复合材料在细晶强化和弥散强化的共同作用下,硬度比NiCu合金提升了19%。摩擦磨损实验结果表明,未熔WC颗粒能够阻碍对磨球对NiCu合金基体的磨损,WC颗粒以及枝晶间的碳化物形成了弥散强化效应,使磨损机制由黏着磨损转变为磨粒磨损,磨损量减少了56%。Objective NiCu alloy is a crucial material used in the aerospace industry and petrochemical and other fields because of its excellent corrosion resistance,thermal conductivity,and ductility.However,problems of low hardness and poor wear resistance need to be solved to extend its service life and expand its scope of application.Currently,laser-directed energy deposition(L-DED),with a Gaussian or near-flat-top laser heat source,is applied to fabricate metal-ceramic composites to improve their performance,and the ceramic particles employed include tungsten carbide(WC),titanium carbide(TiC),and titanium nitride(TiN).However,proven drawbacks have been reported using these heat sources;these include easily emerging cracks,higher temperature gradient,greater residual stress,and an uneven distribution of WC particles.Meanwhile,laser oscillation provides a new technological approach for LDED.Some research has offered evidences that employing this advanced technology in L-DED can mitigate the above-mentioned defects.In this study,NiCu alloy and NiCu/30%WC composite materials are fabricated by L-DED with a circular oscillating laser beam to improve the hardness and wear resistance of NiCu alloy and reveal the strengthening mechanism.This work can provide technical and data references for the preparation of new wear-resistant composite materials.Methods The experimental materials are NiCu alloy powder and spherical WC particles(Fig.1),with average particle sizes of 45‒106μm and 53‒109μm,respectively.A circular oscillating laser beam is chosen as the heating source to conduct the experiment,and the process parameters are given in Table 2.The laser beam shape is converted into a circular ring by a pair of scanning galvanometers.Upon irradiation with the high-energy laser,the substrate is partially melted,resulting in the formation of a molten pool on the surface.Compared with a Gaussian laser,forced convection occurs in the molten pool as a result of the stirring effect of the circular oscillating laser beam(Fig.2).The p

关 键 词：激光技术 激光沉积 合金 组织 摩擦磨损 

分 类 号：TG148[一般工业技术—材料科学与工程]