Deformation and cavitation at the spherulite scale of semi-crystalline polymers - Publications du laboratoire QUARTZ - IPGP Access content directly
Preprints, Working Papers, ... Year : 2023

Deformation and cavitation at the spherulite scale of semi-crystalline polymers

Olga Klinkova
Cristian Ovalle
Thilo F. Morgeneyer

Abstract

Engineering stress-strain curves have been generated from tensile tests on semi-crystalline thermoplastics, which may exhibit non linearity and/or peak stress associated with striction/necking phenomenon of the specimen at the macroscopic scale. This work addresses this state of deformed specimen, on an isotactic polypropylene, where irreversible strains have led to a variable cross sectional area along the necked region. 3D images in this region, obtained by using Synchrotron Radiation Computed Tomography with two high resolutions were exploited. The best resolution (1 pixel length = 0.05μm) allowed a better understanding of the morphology of several deformed spherulites within which polar fan arrangements were clearly detailed. Thanks to the identification of the boundaries of spherulite patterns, with a 0.7μm resolution, the longitudinal and transverse elongations of larger numbers of spherulites were measured. The evolution of the volumetric plastic strains due to cavitation at the spherulitic scale along the necked regions, was comprehensively analysed. Volume changes at this scale were highlighted, consisting of increases in the case of void growth followed by a decrease (compaction) at large strains due to the collapse of elongated voids. The effects of these results on the establishment of reliable constitutive model are discussed.
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Dates and versions

hal-04100630 , version 1 (17-05-2023)
hal-04100630 , version 2 (07-09-2023)

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  • HAL Id : hal-04100630 , version 2

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Lucien Laiarinandrasana, Olga Klinkova, Cristian Ovalle, Peter Cloetens, Thilo F. Morgeneyer. Deformation and cavitation at the spherulite scale of semi-crystalline polymers. 2023. ⟨hal-04100630v2⟩
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