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The performance of thermoplastic materials under a constant applied stress may also be considered in terms of creep rupture. Creep rupture indicates the maximum loading a material will sustain for a given period before it fails, where failure is defined as brittle or necking deformation. Figure 11 shows tensile creep rupture data versus time for natural and reinforced PEEK polymer materials.
Figure 11 - Tensile Stress Versus Time for PEEK™ Polymer Materials at 73°F (23°C)
Figure 11 shows that there is little difference between the grades at ambient temperatures over the time-scale tested. Therefore, experiments were performed at elevated temperatures (Figure 12).
Figure 12 - Tensile Stress Versus Time for PEEK™ Polymer Materials at 302°F (150°C)
Figure 12 shows the effect of fiber reinforcement and orientation for PEEK polymer materials. The angles indicate the direction of testing with respect to melt flow. 450CA30 exhibits superior creep rupture performance over the other materials tested and to most high performance thermoplastics. Therefore, 450CA30 materials are often used to form components which experience permanent loading at high temperatures.
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