Indentation Responses and Damage in Kaolin/Cellulose-Fibre Epoxy Nanocomposites

摘要

The nature and degree of indentation responses as well as the deformation-microfracture damage in the vicinity and below the Vickers contacts in epoxy composites reinforced with cellulose-fibre (CF) and nano-sized kaolin have been studied. The hardness of the nanocomposite is load-independent but is time-dependent as a result of both viscoelastic deformation and extensive microscale damage. A pronounced shear deformation within the CF/epoxy matrix is observed during indentation, indicating microscale quasi-plasticity which can be associated with interfacial sliding, interfacial debonding, and microcracking. However, no contact-induced cracks are observed and the extent of micro-damage distributed within the shear-compression zone around and below the contacts is profoundly suppressed as the thickness of the harder kaolin/epoxy layer increases.