Page 5 - report P Lemoine feb 2013c

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2. EXPERIMENTAL PROCEDURES

2.1 Sample preparation

Nanoindentation is a technique which uses a diamond indenter to push and pull from a
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flat sample surface. The analysis of the load (L) and displacement (d) during this cycle
gives information on the elastic and plastic properties of the sample. The two quantities

of interest are the elastic or Young modulus (E), which usually compares well to E value
calculated by other testing techniques (uniaxiale tension, bending, etc.) and the harness
H, which represents the load over projected area (H=L/A) and which corresponds to the

plastic deformations in the sample (ie the harder is a sample, the less plastic
deformation)

Y asrec no Y asrec

Figure 1: Optical micrographs of the polished Y asrec and no Y asrec samples (micron
bar= 100mm)

As nanoindentation can only be carried out on smooth surfaces, the specimen needed to

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be polished. These samples, approximately 3 mm thick and 1 cm area were first
embedded in epoxy resin mould 3cm in diameter. A Struers mechanical polisher was

used. Initial attempts using an aqueous media proven unsuccessful, due mainly to the
partial solubility of the cement. Isopropanol (IPA) proved a much better medium (samples

showing mass loss < 0.1wt.% following a 20 min ultrasonication). The polishing was
carried out using a series of SiC foils, from grit 300 to grit 2000. A key perquisite is to

polish the no Y asrec sample separately as this specimen results in fragments which

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