Twin thickness and dislocation interactions affect the incoherent-twin boundary phase in face-centered cubic metals

Abstract

Incoherent-twin boundaries (ITBs) can significantly affect the mechanical properties exhibited by metals. Although numerous studies have been conducted to date, the atomic structures of such ITBs remain unclear, owing to difficulties in imaging their structure. In this study, high-angle annular dark-field imaging was used to reveal the atomic structure of the ITBs present in Pt. We discovered that both the twin thickness and the dislocation-ITB interaction can affect the ITB phase structure. In thin twins, the {111} planes between the ITB remain flat without any obvious displacement along the <111> direction, whereas in thicker twins, the {111} planes between the ITB exhibit clear displacement along the <111> direction, with this displacement increasing as the twin thickness increases. The ITBs frequently absorb full dislocations, which leads to the formation of dislocation-misaligned ITBs. This twin-thickness effect and dislocation-ITB interaction, which resulted ITB-phase variation, has rarely been reported.