利用分子动力学方法探究铁素体-渗碳体相界面效应

Research on the interface effect of ferrite⁃cementite phase by molecular dynamics

珠光体是十分重要的组织结构,因此本文构建了含铁素体-渗碳体相界面的模型,并采用分子动力学模拟方法模拟纳米压入的过程.通过对模拟结果的力学性能和组织结构分析,探究了铁素体-渗碳体相界面效应.研究发现,距铁素体-渗碳体晶界不同距离(位置压入),在压入最初阶段,压头载荷随着压头与晶界距离的增大而增大,当压入深度达到一定深度后,载荷随着距离的增大而减小.杨氏模量和最大剪切模量受压头尖端下方原子结构的直接影响,硬度受到结构完整性和类型的共同影响.铁素体-渗碳体相界面影响了纳米压入过程中位错形核、增殖和扩展,宏观表现为在相同压入深度下,不同压入位置压头载荷的差异.

Pearlite is a very important microstructure.Therefore,a model of the ferrite-cementite phase inter⁃face is constructed in this paper,and the process of nano-intrusion is simulated by molecular dynamics simula⁃tion method.By analyzing the mechanical properties and microstructure of the simulation results,the ferrite-ce⁃mentite phase interface effect was explored.It is found that the indenter load increases with the increase of the distance between the indenter and the grain boundary at different distances(positions of indentation)from the ferrite-cementite grain boundary.When the indentation depth reaches a certain depth,the load decreases with the increasing distance.Young’s modulus and maximum shear modulus are directly affected by the atomic struc⁃ture below the indenter tip,and hardness is affected by both the structural integrity and type.The cementite phase interface affects the nucleation,proliferation and expansion of dislocations during the nano-indentation process,and the macroscopic performance is the difference of the indenter load at different indentation positions under the same indentation depth.