Research On Laser-assisted Micro-milling Of TC4Titanium Alloy

Hard-to-machine materials such as titanium alloys have excellent characteristicssuch as high strength, high hardness and high heat resistance. In recent years, they arewidely used in aerospace industry, vehicle engineering, biomedical fields etc. However,the poor quality of the machined surfaces and high tool wear rates during traditionalmechanical processing make these materials difficult to machine, which is much morecomplex in micro-machining field due to microscale effect. To solve such problem,laser heating is employed in the process of micro-milling TC4titanium alloy in thisthesis.A thermal differential equation is established on Fourier’s law and the law ofconservation of energy, based on which a transient, three-dimensional thermal modelwith moving heat source is established in ABAQUS. Then it is validated by temperatureexperiments. Using the model, systematical investigations in the effects of varied laserparameters on temperature field distribution are conducted.In order to study the feasibility of laser-assisted micro-milling, this article conductsthe research with modeling and experiments. Firstly, a finite element model isestablished by ABAQUS/Explicit based on the law of Johnson-Cook Damage and thesimulation model is utilized to study the procedure of producing chips and the theoriesof scaling effect. What’s more, the comparison of cutting force between traditionalmicro-milling and laser-assisted micro-milling is conducted to partly validate itsfeasibility. When it comes to the study of experiments, cutting force, the quality ofmachined surfaces, the extent of elemental diffusion and tool wear are chosen as theevaluating indicators to systematically validate the feasibility of laser-assistedmicro-milling.Finally, the orthogonal experiment designing method is utilized to thoroughlystudy the cutting force with different technological parameters and the experienceformula on experimental data is also got by nonlinear fit. Subsequently, SEM and EDXare used to test tool wear during the procedure of laser-assisted micro-milling.