University of Manchester

Freeze Cast Aerogel; A Multi-Scale In Situ Compression and Dital Volume Correlation Study

Shelley Dyan Rawson

Scientific Case

X-ray Micro-CT imaging of freeze cast aerogel during in situ compression. The sample will be imaged at multiple length-scales during compression, to show structural changes to the whole sample, different domains within the sample, and the individual sheets of the aerogel, revealing the multi-scale relationship between structural architecture and mechanical properties.

Experiment Design

Sample size is 1cmx1cmx1cm.
Features of interest (on the sub-micron scale) are sheets of material, approx. 200nm in thickness, spaced 25 microns apart. Preliminary scans demonstrate that these features can be clearly observed using the Versa 520 using voxel size of 0.3 microns and phase contrast.
Compression will be applied using the 5kN Deben rig and Digital Volume Correlation will be performed using DaVis (LaVision)
The sample will be imaged in the initial, un-compressed state, at low <16 hours> and high <7 hours> resolution (low resolution scans require long scan times I think because features are much smaller than voxel size) A radiograph will also be taken of the whole sample. A 2mm displacement will be applied to the sample. The sample will then be imaged again. 6 scans will be performed in total to observe the following positions: uncompressed, 2mm, 4mm, 6mm, 8mm, 10mm (fully compressed- the sample will compress to approx. 50micron thickness).
Scanners and Rigs
Xradia VersaXCT
Compression will be applied using the 5kN Deben rig

Sample & Safety

Sample is a 1cm cube of freeze cast aerogel. No hazards associated with the aerogel sample.
Low Hazard

Scan Records

Project Report