Civil Engineering Reference
In-Depth Information
Fig. 8.15
3D microstructure
of as-received material
(sample 1) showing
orientations
1
,
2
, and
3
Figure
8.15
displays a 3D representation of the as-received material microstruc-
ture along with the three material orientations.
For orientation 1, the average grain size is 6.34 µm with a standard deviation
of 2.46 µm and orientation 2 has an average grain size of 6.35 µm with a standard
deviation of 2.15 µm. Again, since this sheet was warm-rolled, there is no sign of
residual cold work in these orientations as verified by the lack of twin boundaries.
The grain size of the as-received material in orientation 3 is 4.93 µm with a
standard deviation of 1.71 µm which is typical for this Mg alloy and for a warm-
rolled sheet. Also, since this sheet was warm-rolled, there should not be an abun-
dance of cold work instilled into the material. This is visually verified as the
micrographs do not appear to display much or any significant amount of twinning.
A twin boundary would appear similar to that of a grain boundary, but it would be
slicing through the grain linearly.
The numerous measurements taken on each micrograph allow for a distribution
of measurements to be generated as shown in Fig.
8.16
. The data presented in this
figure use the as-received material in orientation 3 as an example. From examining
the distribution, the data set appeared to follow a lognormal distribution. This type
of distribution was verified by performing a lognormal distribution test, and the
results are presented in Fig.
8.17
. As shown, a
p
-value of 0.961 resulted from the
test which is highly suggestive that the data set of grain sizes is represented well
by a lognormal distribution.
In addition to examining the distribution of the data set, several micrographs
were taken on the same sample in the same orientation to ensure that the results
