Study On Nanometric Cutting Mechanism Of Lutetium Oxide Single Crystal

The applications of laser devices with a high power tend to be greater with the development of laser technology.Favored by its excellent properties such as low phonon energy,great chemical stability and high damage threshold,lutetium oxide(Lu₂O₃)becomes a promising laser crystal material for solid state laser.In order to meet the requirements of high power and long service life,we need to obtain a damage free or low damage machined surface.However,Lu₂O₃ is a kind of hard and brittle material which would yield cracks and scratches easily during machining process.It is of great significance to figure out nanometric cutting mechanism of lutetium oxide as well as surface/subsurface damage distribution during machining,which could not only guide the subsequent machining experiments but also optimize machining parameters.At present,there's no report on its machinability,and its nanometric cutting mechanism remains unclear.Combining with molecular dynamics analysis and micro-nano scale mechanical experiments,this paper explores the deformation mechanism and material removal law of lutetium oxide during machining.The main research works are described as follows:1.Establish both empirical pair potential function and the first principle pair potential function to describe the interaction between particles inside lutetium oxide.Evaluate two potential functions from the aspects of equilibrium lattice constant,dynamic stability,and mechanical parameters.The mechanical parameters obtained by empirical pair potential are very close to the results of experiments conducted on lutetium oxide single crystal.2.The simulation model of lutetium oxide cutting is established to study the influence of different cutting parameters on the deformation behavior of materials,and the laws of internal damage distribution are obtained.3.Micro-nano scale mechanical experiments were carried out on lutetium oxide single crystal.Combined with the results of MD simulation,a new concept that different cutting speed range would behave distinct trend of crack formation is proposed.