The Influence of Adherend Topography on the Fracture Toughness of Aluminium-Epoxy Adhesive Joints in Humid Environments

Abstract

The adherend surface topography has ;I dramatic effect on the durability of structural bonds formed between aluminium and an epoxy adhesive. Systematic changes in the micro-roughness of an aluminium adherend were achieved using an ultra-milling technique to prepare surfaces with topographies ranging from ultra-flat to a sawtooth profile with a base angle of approximately 60' and a peak-to-valley depth of 10 pm. The fracture toughness of double-cantilever beam specimens, stressed in the Mode I direction and exposed to a humid environment was found to change by a Factor of approximatcly one hundred as the sawtooth profile angle was increased. These changes in fracture toughness may be accounted for through complex interrelationships between moisture diffusion and interphase mechanical properties. each with a strong dependence on the surface micro-topography. k'e~w~ordv: Surrace roughness: Fracture toughness: Bond durability: Aluminium: Epoxy adhesive

Surface Energy and Adhesion in Composite–Composite Adhesive Bonds

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Strategies for the replacement of chromic acid anodising for the structural bonding of aluminium alloys

“…The high energy, easily wettable, nano-rough, porous structure provides the opportunity for interphase formation and stress redistribution within the bondline, as discussed by Packham 32 , Rider and Arnott 124 and others. The relatively thick, amorphous oxide provides barrier corrosion protection.…”

Fracture Toughness of a Silane Coupled Polymer-Metal Interface: Silane Concentration Effects

“…Both surface topology and surface chemistry play vital roles in polymer-metal joint performance. Rider and Arnott used an ultra milling technique to show that change in metal micro-roughness can lead to a two decade change in the fracture toughness of aluminum-epoxy joints [7]. Zhang et al [8], using a different epoxy system, started with one mm diamond polished aluminum and created micro-roughness using both SiC grinding paper ranging from 60 to 600 grit and an oxidation process.…”