Figure 2: Results of behavior under fatigue; (A) total cycles x expose
time, (B) softening cycles x expose time, (C) softening strain x expose
time, (D) strain variation.
In addition, the lifetime of the exposure condition of 575 h indicated a
progressive upward trend but was still less than that of non-irradiated
material. This result is possibly related to the surface conditions of
the specimens and the depth of the degraded layer, which were not
measured in this study.
The surface hardness of the samples was characterized using a Vickers
meter; the results are presented in Table 3. The sample data exhibited a
normal and homogeneous distribution along the surface of the specimens.
The results of this analysis showed that there was a difference in the
conditions evaluated. The mean hardness for all the irradiated samples
of PS evaluated was significantly greater than that of the ”as
received” PS. However, the irradiated groups showed statistically
similar values, suggesting a saturation of the superficial degradation
of this material.
Table 3: Average values of Vickers microhardness.