Fatigue behaviour of mineral filled polyamide 6-6
- ENSAM, Paris (France)
The flexural fatigue at 10Hz, 23 {+-} 2{degree}C and various deformation amplitudes ({var_epsilon} = 1.4, 2.2 and 3.1%) was studied for various PA 66 samples containing mineral fillers in low (<5%) weight fraction. The fillers were talc, mica and wollastonite having a very different granulometry and aspect ratio. A preliminary DSC investigation showed that all these minerals display a nucleation effect of PA 66 crystallization, their efficiency being in the order talc>mica>wollastonite. Stress recording during the fatigue testing allows to detect the rupture, which occurs generally in a brittle (sudden) mode. When fatigue testing is made in dry state, the sample compliance remains constant during the whole test duration, for low stress levels. For high stress levels, in the case of unfilled and mica filled samples, the stress decreases rapidly in the first 10% of the lifetime and reaches a plateau value corresponding to about 50% of the initial stress amplitude. In situ measurements of the surface temperature show that the initial stress decrease is due to self heating above the glass transition temperature (60{degree}C) of the polymer. In all the cases, the presence of a filler-despite its very low concentration-reduces significantly the lifetime. Similar tests were made in wet state (2,5 % absorbed water). In this case, the behavior observed only for high stress levels in mica and unfilled samples in dry state appears in all the cases here, which is obviously linked to the lower Tg value due to plasticization of PA 66 by water. The role of fillers in fatigue damage and rupture will be discussed on the basis of the above results and complementary SEM observations.
- OSTI ID:
- 143591
- Report Number(s):
- CONF-930246-; ISBN 0-87339-251-5; TRN: IM9413%%101
- Resource Relation:
- Conference: Advanced composites `93: international conference on advanced composite materials (ICACM), Wollongong (Australia), 15-19 Feb 1993; Other Information: PBD: 1993; Related Information: Is Part Of Advanced composites 1993; Chandra, T. [ed.] [Univ. of Wollongong (Australia)]; Dhingra, A.K. [ed.] [DuPont, Wilmington, DE (United States)]; PB: 1464 p.
- Country of Publication:
- United States
- Language:
- English
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