Oniszczuk-Świercz Dorota, Świercz Rafał
Institute of Manufacturing Technology, Faculty of Mechanical and Industrial Technology, Warsaw University of Technology, Narbutta 85, 02-524 Warsaw, Poland.
Materials (Basel). 2023 Aug 4;16(15):5476. doi: 10.3390/ma16155476.
The Selective laser melting (SLM) technology of recent years allows for building complex-shaped parts with difficult-to-cut materials such as Ti6Al4V alloy. Nevertheless, the surface integrity after SLM is characterized by surface roughness and defects in the microstructure. The use of additional finishing technology, such as machining, laser polishing, or mechanical polishing, is used to achieve desired surface properties. In this study, improving SLM Ti6Al4V alloy surface integrity using wire electrical discharge machining (WEDM) is proposed. The influence of finishing WEDM cuts and the discharge energy on the surface roughness parameters Sa, Svk, Spk, and Sk and the composition of the recast layer were investigated. The proposed finishing technology allows for significant improvement of the surface roughness by up to 88% (from Sa = 6.74 µm to Sa = 0.8 µm). Furthermore, the SEM analyses of surface morphology indicate improving surface integrity properties by removing the balling effect, unmelted particles, and the presence of microcracks. EDS analysis of the recast layer indicated a significant influence of discharge energy and the polarization of the electrode on its composition and thickness. Depending on the used discharge energy and the number of finishing cuts, changes in the composition of the material in the range of 2 to 10 µm were observed.
近年来的选择性激光熔化（SLM）技术能够制造由诸如Ti6Al4V合金等难切削材料制成的复杂形状零件。然而，SLM后的表面完整性表现为表面粗糙度和微观结构缺陷。使用诸如机械加工、激光抛光或机械抛光等额外的精加工技术来获得所需的表面性能。在本研究中，提出了使用电火花线切割加工（WEDM）来改善SLM Ti6Al4V合金的表面完整性。研究了精加工WEDM切割和放电能量对表面粗糙度参数Sa、Svk、Spk和Sk以及重铸层成分的影响。所提出的精加工技术能够将表面粗糙度显著改善高达88%（从Sa = 6.74 µm降至Sa = 0.8 µm）。此外，表面形貌的扫描电子显微镜（SEM）分析表明，通过消除球化效应、未熔化颗粒和微裂纹的存在，表面完整性性能得到了改善。重铸层的能谱分析（EDS）表明，放电能量和电极极化对其成分和厚度有显著影响。根据所使用的放电能量和精加工切割次数，观察到材料在2至10 µm范围内的成分变化。
