α-Fe<110>倾侧晶界单轴拉伸下位错演变的分子动力学模拟

Molecular Dynamics Simulation of Dislocation Evolution in α-Fe <110> Tilt Grain Boundary Under Axial Tensile

采用分子动力学方法通过建立单轴拉伸条件下α-Fe<110>倾侧晶界模型,研究α-Fe<110>倾侧晶界及空洞周围位错发射、增殖演变过程.结果表明:α-Fe在塑性变形阶段与解理断裂微裂纹形核时会发射1/2<111>全位错并随着拉伸加载而呈指数型增殖,且内部位错相遇扩展分解得到<100>或<110>不全位错;此外,纳米空洞的存在提前了基体内部位错产生的时间,加快了位错密度的增长,但并不影响位错的增殖速度.

The molecular dynamics method was used to establish α-Fe〈110〉 tilt grain boundary model under axial tensile, the evolutions of dislocation growth and propagate around the grain boundary and nano-void of α-Fe〈110〉tilt grain boundary were simulated. It shows that α-Fe can emit 1/2% 111 perfect dislocationat at the beginning of plastic deformation and the site of micro-crack nucleation before cleavage crack,which will growth and propagate exponentially and decomposed 〈100〉 or 〈110〉 partial dislocation during the dislocation evolution along the tensile loading; the nano-void advance the dislocation segment and promote the tendency of the dislocation density increasing, but the propagate rate of dislocation is unaffected.