The experimental study on recast layer removal of metallic material by femtosecond laser

The microcracks and impurities in the recast layer have undesirable effects on the fatigue resistance and service life of metallic parts. In order to overcome the drawbacks, a new method of recast layer removal based on the advanced femtosecond laser process technology is proposed in this paper. For the purpose of efficient material processing, the comparative experiments in type Ti-6Al-4V titanium alloy were carried out using femtosecond laser, respectively by means of horizontally bedded and vertically shifting scanning processing. The test results using the Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Detector (EDX) show that the horizontally bedded scanning method is better than the other method in respect of material removal rate and the quality of machined surface; based on the horizontally bedded scanning processing, the recast layer caused by conventional machining methods could be removed effectively by femtosecond laser; and the new recast layer doesn't appear again on the microstructure surface in this process. Thus, the finish machining technology using femtosecond laser could act as an effective and promising tool for the non-recast layer microstructures machining.