Research On TiNi Hole Quality Based On Femtosecond Laser

TiNi shape memory alloy is a new multifunctional special material.This kind of metal compound with deformation recovery ability is widely used in the field of artificial organs.However,due to the hardness of the material and the difficulty of micro hole machining,the traditional machining method can not meet the requirements of TiNi shape memory alloy fine machining.At present,femtosecond laser as a new processing method has great application prospects.Because of its very short pulse width and high single pulse energy,it has significant advantages in the precision processing of hard brittle and high melting point materials.Therefore,this paper uses femtosecond laser to process TiNi memory alloy micropores.By analyzing the principle of the interaction between femtosecond laser and TiNi shape memory alloy,simulating its processing process with MATLAB,obtaining the ablation threshold and the temperature change rule in the process of processing TiNi memory alloy,establishing the depth model of the micro groove ablated by femtosecond laser,analyzing the heat affected zone formation in the process of ablation,and carrying out multi factor orthogonal experiment,the processing of TiNi shape memory alloy by femtosecond laser is studied Processing technology of micropores.In this paper,the mechanism of material processing by femtosecond laser is studied.The process of interaction between femtosecond laser and TiNi memory alloy is simulated by using the simplified two temperature equation by using the finite difference method in MATLAB.The changes of surface electron and lattice temperature of TiNi memory alloy when the parameters of femtosecond laser and TiNi memory alloy are changed are analyzed According to the scanning electron microscope and mathematical model,the ablation threshold of TiNi memory alloy was solved and the law of selective ablation was obtained.The influence of the accumulation effect of femtosecond laser pulse on the processing results was discussed.The mechanism and process of femtosecond laser processing materials were studied and established The ablation depth model of femtosecond laser ablative materials was established,and the correct depth model was obtained by modifying the parameters of the model after experimental verification.The formation of the heat affected zone and the method of reducing the depth of the heat affected zone in the processing of TiNi memory alloy by femtosecond laser were studied.The effects of laser power,scanning speed,scanning cycle times and the defocusing amount of femtosecond laser spot on the burning were analyzed by experiments At last,the effects of laser pulse energy,pulse number,radial feed rate,scanning speed and other processing parameters on the quality and accuracy of TiNi memory alloy micropores are analyzed.