Estimation of directional single crystal elastic properties from nano-indentation by correlation with EBSD and first-principle calculations

• Published in: Materials & design Vol. 234; p. 112296
• Main Authors: Seehaus, Mattis, Lee, Sang-Hyeok, Stollenwerk, Tobias, Wheeler, Jeffrey M., Korte-Kerzel, Sandra
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2023; Elsevier
• Subjects: Austenitic steel; DFT; EBSD; EDS; Least-squares optimisation; Meteorite; Nano-indentation; Stiffness tensor; Stiffness tensor; DFT; Meteorite; EDS; Nano-indentation; Austenitic steel; Least-squares optimisation; EBSD
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2023.112296

[Display omitted] •Correlation methodology for measurement techniques like nano-indentation, EBSD, SEM and DFT.•Deployment of a two-step optimisation strategy to estimate the single crystal stiffness tensor.•High statistical relevance due to high speed nano-indentation.•Applicable for any cubic material. In this study, a two-step optimisation process for the estimation of the single crystal stiffness tensor from the indentation modulus is presented. This was accomplished by using a 2-dimensional data correlation method for nano-indentation, EBSD and ab initio data, as well as EDS for phase separation in a multi-phase material. Here, a single-phase Fe-24Ni-0.4C austenitic steel and a two-phase Fe-9.5Ni-0.5Co Seymchan meteorite were used as example materials. In a first step, the combination of high-speed nano-indentation mapping data with elemental and orientation distribution maps allowed the estimation of indentation moduli along specific crystal surface planes normal directions, (001), (011) and (111) using a least squares optimisation based on starting values from DFT or experimentally determined stiffness tensors. A second global optimisation step to estimate the single crystal stiffness tensor using pre-solved solution parameters of the Vlassak-Nix equations yielded reasonable correspondence between the experimentally determined stiffness tensors from correlative nano-indentation data and other methods. The presented method demonstrates generally the possibility to derive directionally sensitive elastic properties from high-speed nano-indentation for cubic materials statistically.