Regensburg 2019 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 18: Interfaces

MM 18.1: Talk

Tuesday, April 2, 2019, 14:15–14:30, H45

Influence of Ta and Zr segregation on the atomic structure of [111] tilt grain boundaries in Copper — •Thorsten Meiners, Christian H. Liebscher, and Gerhard Dehm — Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf

Recently, nanocrystalline Copper (Cu) has been investigated intensively, because of its excellent properties such as high strength and hardness. However, at elevated temperatures rapid grain growth causes a destabilization of the microstructure. Therefore, alloying Cu with immiscible elements such as Zr and Ta has shown to greatly stabilize the microstructure induced by strong grain boundary (GB) segregation and precipitation. In our study we investigate the atomic structure of these GB segregation and precipitation phenomena at [111] tilt GBs in Cu by aberration-corrected (scanning) transmission electron microscopy in order to identify the atomistic mechanisms of the microstructure stabilization. We found spherical Ta_{x}O nano particles at the GBs, which locally distort the GB plane and can thus lead to Zener pinning. Zr is found to form a kind of glass-phase, which is inhomogenously distributed at the GBs. Especially GB steps are strongly decorated with nanometer sized Zr-rich inclusions. In addition we observe Zr-induced structural transitions compared to clean GBs, indicating that these local chemical states alter the GB properties.