Aiming at the film cooling holes machining of nickel-based single crystal material by picosecond ultrashort pulsed laser

physical depth of field microscope is used to determine the geometry of the film cooling holes

meanwhile the cavity lumen surface of the membrane pore is observed by optical microscopy. Performances of porous film samples prepared by two processes of picosecond ultrashort pulsed laser and electric discharge using high temperature and low cycle fatigue equipment are compared

and specimen fracture is analyzed by scanning electron microscope (SEM) to evaluate the performance. The results show that the entering and exiting holes surface can avoid ablation by picosecond ultrashort pulsed laser processing step by step and effective control of energy density. While the geometric accuracy can meet the design specifications

also there is no remelting layer

intermittent beads

arcing and micro-cracks and other defects in the cavity. Besides

the surface integrity of the film holes after processing could be effectively improved. The comparative tests of high temperature low cycle fatigue performance of picosecond ultrashort pulsed and EDM film show that the cycle number of sample perforated by picosecond ultrashort pulsed laser is as many as three times that of EDM. SEM of high temperature low cycle fatigue fracture shows that the two kinds of processing specimens are cleavage fracture

without metallurgical defect

the remelting layer formed by EDM drilling may contribute to the fracture

and there is no obvious remelting layer in ultrashort pulsed laser drilling.