Effects of picosecond laser power variation on laser-induced changes of titanium

Abstract

In order to understand the influence of picosecond laser parameter variation on laser-induced changes of titanium, the sheet surfaces of titanium were irradiated by picosecond laser pulses with different average laser power in this work. Then X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) were used to analyze the influences of average laser power variation on final chemical composition and microstructure of the ablated titanium, respectively. With the average laser power increasing from 4mW to 30mW, it is found that the main ablation products of titanium were both TiO2 and TiC, and the contents of TiO2 and TiC among ablation products continuously rose; meanwhile, the content ratio of TiO2 to TiC kept falling. Besides that, the increase of average laser power intensified the amorphization degree of microstructure of ablated titanium. Finally, it is concluded that the increased laser fluence resulted from average laser power increasing, which intensified the heat accumulation effect on titanium surfaces. Then, the thermal and mechanical damages were deepened and enlarged in the laser ablated zone.