Nanoscale Resolution Deformation Measurements at Crack Tips of Nanostructured Materials and Interface Cracks

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The trend towards the application of nanoparticle filled materials in the aerospace and automotive electronics sectors have led to a strong need in material characterization on the micro and nano scale. In addition MEMS and sensor applications are used in higher temperature and under combined loading (e.g. temperature, vibration, moisture). Another challenging task is the development and evaluation of interface concepts of biological structures to microelectronic materials such as polymers, metals, ceramics and semi-conducting materials. To fulfil these needs new strategies for reliability assessment on the submicron scale are essential. Under this prerequisite Scanning Probe Microscopy (SPM) serves as the basis for the development of the nanoDAC method (nano Deformation Analysis by Correlation), which allows the determination and evaluation of 2D displacement fields based on SPM data. In-situ SPM scans of the analyzed object are carried out at different thermo-mechanical load states as shown in Fig. 1. In the illustrated case a Scanning Force Microscopy topography signal serves as the imaging technique. The obtained images are compared utilizing digital image correlation (DIC) based on grayscale cross correlation algorithms. This allows the tracking of local image patterns (compare to Fig. 1) of the analyzed surface structure. The measurement results of the nanoDAC technique are full-field displacement fields. For the images of Fig. 1 the determined vertical (crack opening) displacement field is illustrated in Fig. 2. The nanoDAC method is suited for measurement of mechanical properties such as fracture properties, Young’s modulus, Coefficient of Thermal Expansion, Poisson’s ratio. Furthermore the technique should be used for tracking of structures or particles driven by diffusion processes or nanomanipulators. The paper will focus on new results generated at crack tips fields of carbon nanotube (CNT) filled epoxy systems. Additionally interface crack analysis will be addressed at polymer silicon interfaces.

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Journal: TechConnect Briefs
Volume: 1, Nanotechnology 2008: Materials, Fabrication, Particles, and Characterization – Technical Proceedings of the 2008 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: June 1, 2008
Pages: 904 - 907
Industry sector: Advanced Materials & Manufacturing
Topic: Materials Characterization & Imaging
ISBN: 978-1-4200-8503-7