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DF: Fachverband Dielektrische Festkörper

DF 15: Ceramics and Applications (DF with KR)

DF 15.2: Talk

Thursday, March 10, 2016, 15:20–15:40, H26

Small-scale Dislocation Plasticity in Strontium Titanate — •Alexander Stukowski, Farhan Javaid, Karsten Durst, and Karsten Albe — Technische Universität Darmstadt

Strontium titanate (STO) is an optically transparent perovskite oxide ceramic material. In contrast to other ceramics, single crystal STO plastically deforms under ambient condition, without showing a phase transition or early fracture. This remarkable ductility makes it a prime candidate for different technological applications. However, while the mechanical behavior of bulk STO has been studied extensively using uniaxial compression testing techniques, little is known about the local, small-scale behavior and the details of dislocation-based nanoplasticity in this perovskite material.

In this contribution we compare results obtained from new nanoindentation experiments and corresponding large-scale molecular dynamics simulations. The evolution of the plastic zone and dislocation structures that form underneath the indenter is investigated using etch-pit methods in experiments and a novel three-dimensional defect identification technique in atomistic computer models. The latter allows tracing the evolution of the complete dislocation line network as function of indentation depth, quantifying the activity of different slip systems, and correlating this information with the recorded load-displacement curves and hardness data.