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.