单晶γ-TiAl合金纳米切削过程的分子动力学模拟

Molecular Dynamics Simulations of Single Crystal γ-TiAl Alloy in Nanometric Cutting Process

采用分子动力学方法研究单晶γ-TiAl合金纳米切削过程,通过对单晶γ-TiAl合金的建模、计算和分析,讨论了不同切削深度和切削速度对切削过程的影响,结果发现:在切削过程中,随着切削深度的增大,切屑体积逐渐增大,切屑中原子排列越来越紧密,位错密度也会随之增大;但随着切削速度的增大,位错密度反而会随之降低。在一定的切削深度和切削速度范围内,切削过程中刀具前方都会产生“V”型位错环,工件的温度和势能也都会相应的增大。特别是,当切削速度为400 m/s时,刀具前方的切削表面上未出现原子错排。

Molecular dynamics simulations were employed to study the nanometric machining process of single crystal γ-TiAl alloy.The influences of different cutting speeds and cutting depths on nanometric cutting process of single crystal γ-TiAl alloy were discussed by molecular dynamics modeling,calculation and analysis.The results show that the accumulated volume of chips increases with the cutting depth increasing in nano-cutting process;at the same time the atoms in the chip stack are tighter and the dislocation density is increased.However,the dislocation density is decreased with the cutting speed increasing.In a certain range of cutting depth and speed,in front of the tool will produce "V"-type dislocation ring of the cutting process,and the temperature and potential energy of the workpiece will increase correspondingly.When the cutting speed is 400 m/s,in particular,there is no atomic misalignment on the cutting surface in front of the tool.