Effect Of Fluence On CuZr Amorphous Alloy Ablated By Femtosecond Laser And Analysis Of No-phase Change Ablation Mechanism

Amorphous alloys is employed as promising materials in varied field because of their excellent mechanical,chemical and physical properties.Although amorphous materials have many advantages,it is metastable and will be crystallized under high temperature or high stress.Its excellent performance is also changed.So the processing of bulk amorphous materials,especially the micro-nano processing is a difficulty in its application.In the process of traditional machining,there produce more heat and stress effect,which makes the atomic structure of amorphous material easily to change.Therefore,the processing method of amorphous materials is extremely important.Femtosecond laser ablating CuZr amorphous alloy was investigated using the molecular dynamics simulation combined with the two temperature model.The main work includes the following content.?1?The effect of femtosecond laser fluence on the electron phonon coupling time of target was investigated.With the increase of laser fluence,the electron phonon coupling time of materials required longer time,and electronic and lattice temperature will be higher.?2?The effect of femtosecond laser fluence on ablation mechanism of CuZr amorphous alloy was investigated.The duration of laser is 100 fs and fluence is selected from 40 mJ/cm² to 200 mJ/cm².The results show that three kinds of ablation mechanisms exist in the process of femtosecond laser ablation of CuZr amorphous alloy.When the laser fluence is 40mJ/cm²,the mechanism of ablation is mechanical spallation;When the laser fluence is 80mJ/cm²,the mechanism of ablation is thermo-mechanical ablation;When the laser fluence is from 160mJ/cm²to 200mJ/cm²,thermo-mechanical mechanism and phase explosion co-exist in the ablation process of target material,and with the increase of fluence,phase explosion becomes the main mechanism of material removal.?3?The radial distribution function is used to analyze the structure of target ablated region.The results show that the copper-zirconium amorphous alloy is obtained by rapid cooling of copper-zirconium crystal alloy.The radial distribution function of the atom in the ablation region of the target corresponds to the atomic structure of the amorphous material in the short-range ordered atomic structure after the interaction of the femtosecond laser with the energy density of 80 mJ/cm² and the CuZr amorphous alloy.When the fluence is increased to 120 mJ/cm²,the atomic structure inside the material remains in a disordered state,and the target iswithout obvious crystallization...