A molecular dynamics study of dislocation-interphase boundary interactions in FCC/BCC phase transformation system

Industrial alloys are often strengthened via the formation of second phase during phase transformation due to the strong barrier of the interfaces between the second phase and the matrix, or interphase boundaries (IPBs), for dislocation propagation. In the present work, molecular dynamics simulation was employed to reveal the atomistic processes of the interactions between the lattice dislocations and face-center-cubic (FCC)/body-centercubic (BCC) IPBs, including the image force on the lattice dislocation, slip transmission and other local reactions between the lattice dislocation and interfacial dislocations. It is found that the image force always attracts BCC lattice dislocation towards the IPB due to the difference in elastic properties of the two phases. With the presence of external force, four dislocation/IPB interaction results were observed among various dislocation-IPB interactions. Detailed analysis were made regarding how influencing factors such as resolved shear stress, continuity of slip systems, local dislocation reaction and dislocation core spread, affect dislocation-IPB interaction results. The present work provides some new insight into an in-depth understanding of how and in what ways IPBs can affect the plastic deformation in alloy systems.

Automated summary

In this study, molecular dynamics simulation was used to reveal the interaction processes between lattice dislocations and IPBs, including image force, slip transmission, and other local reactions. The research found that the image force always attracts BCC lattice dislocations towards the IPB, and observed four different dislocation/IPB interaction results. Detailed analysis was conducted on influencing factors such as resolved shear stress, continuity of slip systems, local dislocation reaction, and dislocation core spread. This study provides new insights into how IPBs can impact plastic deformation in alloy systems.