Effect of hygrothermal treatment on the tensile properties - ethesis ...

Temperature <strong>of</strong> hot press = 100 0 C
Sl.
No.
Duration <strong>of</strong>
Hygrothermal
Treatment, t
(in hrs)
UTS
(MPa)
Displacemnt
at break
(mm)
Energy
to
yield
point
1 0 75.91 1.044 .8510
2 0 79.69 1.117 .9599
3 0 62.68 0.879 .6166
4 0 65.69 0.732 .9234
(J)
Dry
Weight
(in g)
Weight
after
<strong>treatment</strong>
(in g)
%age
increase
5 4 63.79 1.117 .5866 8.40 8.63 2.74
6 4 61.57 1.199 .4484 9.88 10.11 2.33
7 4 75.63 1.071 .6597 8.49 8.72 2.71
8 4 66.68 1.275 .5260 9.04 9.30 2.88
9 4 67.45 1.300 .6645 9.89 10.14 2.53
10 16 64.34 1.401 .2984 9.47 9.90 4.54
11 16 66.01 1.080 .3877 8.73 9.17 5.04
12 16 51.96 1.199 .3326 9.54 9.96 4.40
13 16 57.71 1.318 .2187 8.46 8.89 5.08
14 16 73.08 1.437 .6254 8.93 9.31 4.26
15 16 65.27 1.391 .4108 10.08 10.52 4.37
16 64 51.89 1.172 .3305 11.04 11.45 3.71
17 64 46.55 1.227 .2460 10.97 11.39 3.83
18 64 70.57 1.748 .6780 9.10 9.54 4.84
19 64 77.56 1.556 .4702 9.55 10.03 5.03
Table 4.3: Experimental results obtained for samples hot-pressed at 100 0 C and
subjected to <strong>hygrothermal</strong> <strong>treatment</strong> for 0,4,16 and 64 hours
4.1. Deductions from Stress-Strain curve:
(i) (4 hrs):- The slope <strong>of</strong> the plot is high. That means the samples are more
elastic in nature. The load is bore by the fibre rather than the matrix. From
the drop in 80 0 C, it is clear that the fibre bearing the load suffers from
pullout and then fractures. 80 0 C shows high strength and ductility, 100 0 C
shows progressive failure.
(ii) (16 hrs):- Most <strong>of</strong> the plots show brittle behavior. The termination <strong>of</strong> the
plot at a point signifies that the bonding between the matrix and fibre is
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