选区激光熔化制备IN738LC流道的电化学抛光工艺  

Electrochemical Polishing Process of IN738LC Channels Fabricated by Selective Laser Melting

作　　者：吕海卿 王琦舜 李明川 常帅[1] 李俐群[1,2] LYU Haiqing;WANG Qishun;LI Mingchuan;CHANG Shuai;LI Liqun(State Key Laboratory of Precision Welding&Joining of Materials and Structures,Harbin Institute of Technology,Harbin 150001,China;Zhengzhou Research Institute,Harbin Institute of Technology,Zhengzhou 450046,China)

机构地区：[1]哈尔滨工业大学材料结构精密焊接与连接全国重点实验室,哈尔滨150001 [2]哈尔滨工业大学郑州研究院,郑州450046

出　　处：《表面技术》2024年第20期134-142,157,共10页Surface Technology

基　　金：国家重点研发计划(2022YFB4602500)。

摘　　要：目的改善选区激光熔化制备的流道部件内表面的成形质量。方法采取内置阴极的电极排布方式,对IN738LC流道内表面进行电化学抛光,在磷酸-硫酸体系下对电解液配比进行试验优化,同时确定适用于流道内表面电化学抛光的最佳添加剂(丙三醇)添加量、温度区间、外加电压等主要工艺参数。采用激光共聚焦显微镜与表面轮廓仪测量流道内表面的表面粗糙度以评价电化学抛光效果,并通过光学显微镜对抛光前后流道内表面形貌变化进行对比与分析。结果在60%(体积分数)磷酸与15%(体积分数)硫酸的混合电解液中,IN738LC流道内表面取得了最佳的抛光效果,表面粗糙度降低最多。在每100 mL混合电解液中加入6 mL的丙三醇,可以进一步提高抛光效果;最佳抛光温度为50~60℃;在2.3 V(vs.MSE)的外加电压下,可以实现SLM制备流道粗糙内部表面的高选择性电化学抛光,直流道内表面粗糙度由约10μm降低至1.12μm。结论与常规电化学抛光采用的极限电流平台中间电压1.7 V(vs.MSE)相比,新型过电位电化学抛光所采用的特殊电压2.1~2.3 V(vs.MSE)明显更适用于选区激光熔化成形的复杂流道内表面,在不带来表面损伤的前提下,最大限度地实现了黏附颗粒的选择性去除。在合适的电解液中加入适量甘油使抛光后内表面的熔道轮廓更加平滑,电化学抛光的整体均匀性有所提高。过电位抛光方法在局部选择性和整体均匀性上的优异表现,证明了其在增材制造复杂构件表面光整方面具有极高的应用价值。Selective laser melting(SLM)technology is widely used in the manufacturing of precision and complex components,but the surface roughness has always been a problem that has plagued the further advances of SLM,especially in the context of the increasing complexity of SLMed parts.Among the surface finishing techniques for additive manufacturing,electrochemical polishing(ECP)has the greatest potential to overcome the accessibility limitations imposed by the complexity of components construction.By combining the latest polishing experiments with the previous research,based on the film theory and the various perspectives,the work aims to introduce a new strategy of over-potential electrochemical polishing(OECP)technology to polish the inner surface of IN738LC fluid channels components fabricated by SLM.During the establishment of the polishing system for OECP,the electrode arrangement with built-in tool cathode was adopted to form a uniform internal electric field.The electrolyte was a mixture of phosphoric acid and sulfuric acid and their volume fractions were experimentally optimized.Besides,the optimal main process parameters for electrochemical polishing of the fluid channel inner surface were determined,including the optimal amount of glycerol added,temperature range,and applied potential.The surface roughness of the fluid channel inner surface was measured by confocal laser scanning microscope and surface profilometer to evaluate the electrochemical polishing effect.The morphological changes of the fluid channel inner surface before and after polishing were compared and analyzed by optical microscopy and scanning electron microscopy.As a result,the best polishing effect was achieved on the IN738LC fluid channel inner surface in a mixed electrolyte of 60 Vol%phosphoric acid and 15 Vol%sulfuric acid,and the surface roughness was reduced the most in this electrolyte.Phosphoric acid and sulfuric acid concentrations together affected the dissolution behaviour of IN738LC as the changing ionic concentration affected the

关 键 词：选区激光熔化 流道 内表面 电化学抛光 表面粗糙度 过电位 

分 类 号：TG456.7[金属学及工艺—焊接]