Incidence of nanoscale heterogeneity on the nanoindentation of a semicrystalline polymer: Experiments and modeling

摘要: The nanoindentation of semicrystalline polyamide 6 (PA6) specimens was evaluated by atomic force microscopy with an extremely sharp diamond tip whose apex nominally less than 10 nm in radius. Nanoindentation performed under dry and wet conditions on PA6 samples injection-molded at different melt temperatures. bulk Young’s modulus found to be good agreement the literature, thereby confirming experimental approach developed this study. A major finding is observation sudden increases during loading portion load–displacement curves, which occurred regardless water absorption. We also some irregularity pile-up morphology around indents, linked heterogeneous nature deformation PA6. Finite element analysis used elucidate phenomenon discontinuity independently considering variations elasticity, yield stress friction coefficient crystalline lamellar aggregates It shown that discontinuities nanoindented result from local differences phenomena level. present investigation sheds light importance mechanical heterogeneity emerging contact interactions between nanoscale polymers.