Drilling micro-holes at different orientations on thermal barrier coated Inconel 718 superalloy surface is essential to protect turbine blades while operating in harsh environment. This work analyses integrity of micro drilled ($600\mathrm{\mu }\mathrm{m}$) surfaces on thermal barrier coated Inconel 718 sheets using TiAlN coated carbide micro-drills. Considering spindle speed, drill feed, and workpiece inclination, the drilling experiments were performed under dry environment with $100\mathrm{\mu }\mathrm{m}$ pecking length. Results show that, a higher tool life in terms of drilling length was observed in straight hole drilling at a combination of low speed (1000 rpm) and low feed ($3\mathrm{\mu }\mathrm{m}$/rev). The drilled surface roughness increased with the number of drilled holes and the highest value of roughness was observed to be $1\mathrm{\mu }\mathrm{m}$ R_a on the 13th inclined hole surface. Smaller cavities were observed on the thermal barrier zirconia coated surfaces. In addition, drilled hole surfaces on metal showed alterations such as adhered chip particles and smeared material. Tensile residual stresses were observed in hoop direction and were found increase with the number of hole drilled in both straight and inclined surfaces. The highest compressive residual stress (1075.3 MPa) was observed in the axial direction on the 5th hole surface for inclined hole drilling, which shows an increase in the d spacing between two planes of machined surface.

在苛刻环境下运行时，在隔热涂层的Inconel 718高温合金表面上的不同方向上钻微孔对于保护涡轮叶片至关重要。这项工作分析了微钻的完整性（$600\mathrm{\mu }\mathrm{米}$）表面用TiAlN涂层硬质合金微型钻在隔热涂层的Inconel 718板上进行加工。考虑到主轴转速，进给量和工件倾斜度，在干燥环境下进行了钻孔实验，$100\mathrm{\mu }\mathrm{米}$啄的长度。结果表明，在低速（1000 rpm）和低进给（$3\mathrm{\mu }\mathrm{米}$/ rev）。钻孔表面粗糙度随钻孔数量的增加而增加，观察到最高粗糙度为$\mathrm{1个}\mathrm{\mu }\mathrm{米}$ ř_一个第13倾斜孔表面上。在热障氧化锆涂层表面观察到较小的空腔。另外，金属上的钻孔表面显示出变化，例如粘附的切屑颗粒和污损的材料。在环向观察到拉伸残余应力，发现残余应力随着在直表面和斜表面上钻孔数量的增加而增加。在斜孔钻削的第五个孔表面上，沿轴向观察到最高的压缩残余应力（1075.3 MPa），这表明加工表面的两个平面之间的d间距增加了。