Page 12 - report P Lemoine feb 2013c

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region random
sample Y asrec Y fired Y N2 Y acid no Y asrec
E H E H E H E H E H
mean 23.9 1.2 38.4 4.1 15.8 0.7 19.0 0.8 5.2 0.1
stdv 16.4 1.7 34.0 5.4 11.6 1.0 11.6 1.3 7.0 0.2
COV 68.5 140.1 88.6 132.0 73.5 140.1 61.1 159.9 135.0 188.6
mean ratio 1.00 1.00 1.61 3.44 0.66 0.59 0.80 0.71 0.22 0.11
p-value/ Y asrec - - 0.006 0.000 0.005 0.054 0.066 0.154 0.000 0.000
Figure 7: Tabulated E and H values for random positioning, showing the p-values

with respect to the Y as rec values for a single tail T-test, assuming equal variances.

3.2 Nanoindentation, individual positioning of the indents.

Here the indents were individually positioned on two indentified regions, the crystals

(bright) and the matrix (dark), as shown in the optical micrographs of figure 8.

Y asrec Y fired

crystal
crystal

matrix matrix

Figure 8: Optical micrograph of the polished Y as rec and Y fired samples, showing
the two identified regions (micron bar= 100mm)

Figure 9 shows the two regions as seen from SEM micrographs, clearly the crystal
regions gave a smooth polished whereas the matrix region still retain a high fraction

of surface cracks and imperfections. Cracks at the interface are also seen.

Figure 10 shows typical load displacement curves for the Y asrec and Y fired

samples, for these individually selected regions. The load required to drive the

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