離散転位動力学法を用いた繰り返し荷重下での転位組織の形成に関する研究

抄録

Early in the fatigue failure, ladder-liked structure called Persistent Slip Band (PSB) which mainly composed of edge dislocation dipole is formed. Because the occurrence of intrusion and extrusion around PSB is the trigger of crack initiation, understanding the formation mechanism of PSB is important to control and suppress fatigue failure. A simulation method, Discrete Dislocation Dynamics (DDD), describes motion of interacting dislocations based on theory of dislocation, has been widely used to analyze the PSB formation process. In the DDD framework the long-range dislocation - dislocation interaction is well defined by theory of elasticity. On the other hand, short-range direct core - core interaction is not well defined. Since the distance between dislocations forming dislocation dipole is less than 10nm, elasticity, we obtained the short-range interaction energetics using Molecular Dynamics (MD) method. Using the DDD, we analyzed PSB formation process and dependences of temperature, loading conditions, and model size in copper.