摘要
激光粉末床熔融Inconel 718合金及其复材具有复杂的微观组织,其诱导的选择性溶解使电解加工表面质量较差。采用电解磨削技术对激光粉末床熔融Inconel 718合金及TiB_(2)/Inconel 718复合材料进行后处理加工,重点研究了两种材料超钝化膜的组成,以及在不同进给速度和转速等工艺参数下,微观组织对电解磨削表面质量的影响规律。结果表明,与Inconel 718合金相比,TiB_(2)/Inconel 718复合材料在电解加工过程中形成了更加致密的超钝化膜。TiB_(2)的添加诱导形成了均匀的TiB_(2)/Inconel 718复合材料微观组织。TiB_(2)附着在超钝化膜表面,使超钝化膜更加均匀且不易被电解液冲刷带走。两种材料超钝化膜均由Ni(OH)_(2)、Fe(OOH)、Fe_(3)O_(4)、Cr(OH)_(3)、Cr_(2)O_(3)、TiO_(2)、MoO_(2)、Nb_(2)O_(5)等组成,所添加的TiB_(2)不参与电化学溶解。在进给速度为1.33 mm/s和转速为1000 r/min的条件下,两种材料的表面质量均达到最佳状态,表面无凹坑现象,且杂散腐蚀导致的过切现象明显减弱。此外,建立了电解磨削加工的物理模型以及表面质量的预测模型,为提高激光粉末床熔融合金及其复合材料的电解磨削质量提供了理论支撑和实验依据。
Objective Inconel 718 alloy,renowned for its outstanding hightemperature strength,oxidation resistance,and corrosion resistance,has found extensive applications across aerospace,energy,and other critical sectors.The advent of the additive manufacturing technology,particularly the laser powder bed fusion technology,has opened up novel avenues for the fabrication of Inconel 718 alloy and its composites.Nevertheless,the intricate microstructure of components produced by this technology gives rise to selective dissolution during subsequent electrochemical machining.This phenomenon not only deteriorates the surface quality but also restricts the further expansion of its applications.Methods In this study,laser powder bed fused Inconel 718 alloy and TiB₂/Inconel 718 composite are used to innovatively address the surface quality problem faced by traditional electrolytic grinding.The core purpose of this research is to deeply explore the intrinsic relationship between the microscopic properties of materials and the processing technology,so as to optimize the processing quality and expand the application range of materials.Specifically,this research uses Xray photoelectron spectroscopy(XPS)analysis technology to determine the chemical composition and elemental distribution of the superpassivation films of two materials.Through a detailed analysis of the composition of the superpassivation film,the aim is first to reveal its formation mechanism and the influence on the surface properties of the material during processing,and then to study the parameters of the electrolytic grinding process including different feed rates and rotational speeds and the relationship between the microstructure of materials and the electrolytic grinding surface quality.Scanning electron microscope(SEM)is used to observe the microstructural changes of materials under different process parameters in real time,and the surface quality parameters after electrolytic grinding can be accurately determined in combination with surface roughness measuring instruments and other equipment.Through comprehensive and detailed experimental data collection and analysis,the influence mechanism of microstructure on surface quality under different process conditions is deeply explored.Results and Discussions Compared to Inconel 718 alloy,TiB₂/Inconel 718 composite can form a denser superpassivation film during electrolytic machining.The root cause of this phenomenon is that the addition of TiB_(2)induces the formation of more homogeneous microstructures inside the material.At the microscopic level,the uniformly distributed TiB_(2)particles act as a“backbone”and provide numerous stable attachment sites for the growth of superpassivation films.These sites make the superpassivation film more uniform in the formation process,and due to its strong interaction with the TiB_(2)particles,the superpassivation film can be firmly attached to the TiB₂particles,effectively avoiding being washed away by the electrolyte,thus ensuring the integrity and stability of the superpassivation film and improving the corrosion resistance of the material.Both materials are composed of Ni(OH)₂,Fe(OOH),Fe₃O₄,Cr(OH)₃,Cr₂O₃,TiO₂,MoO₂,Nb₂O₅,and other compounds.It is worth noting that the added TiB₂does not participate in electrochemical dissolution throughout the electrochemical processing process,and mainly plays a role in enhancing the microstructural stability and promoting the formation of superpassivation films in the material.When it comes to the study of the effect of process parameters on surface quality,both Inconel 718 alloy and TiB₂/Inconel 718 composite are available at a feed rate of 1.33 mm/s and a rotational speed of 1000 r/min,the surface quality is at its best,the surface is extremely flat,and there are no pits.At the same time,the gouge phenomenon caused by stray corrosion has been significantly improved,and the gouge amount has been greatly reduced.Conclusions Compared with Inconel 718 alloy,the nanoTiB_(2)particles in the microstructure of TiB_(2)/Inconel 718 composite are diffusely distributed in the dendrite,which forms a denser superpassivation film in electrolytic machining,and the optimal parameters in electrolytic grinding are 1.33 mm/s and 1000 r/min,in which the volumetric electrochemical equivalent of Inconel 718 alloy is 1.727 mm^(3)/(A∙min),and the volumetric electrochemical equivalent of TiB_(2)/Inconel 718 composite is 1.796 mm^(3)/(A∙min).
作者
翟长帅
郭鹏飞
王飞
杨奇
王震
耿建峰
王慧君
于君
林鑫
Zhai Changshuai;Guo Pengfei;Wang Fei;Yang Qi;Wang Zhen;Geng Jianfeng;Wang Huijun;Yu Jun;Lin Xin(Shandong Engineering Research Center for Additive Manufacturing,Qingdao University of Technology,Qingdao 266520,Shandong,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,Shaanxi,China)
出处
《中国激光》
北大核心
2025年第12期142-153,共12页
Chinese Journal of Lasers
基金
国家自然科学基金(U22A20189,52005280)。
