Evaluation of some machining processes as adherend surface treatments in bonding aluminium

Abstract

—This paper reports detailed studies on some machining processes used as adherend surface preparation methods. The two conventional treatments of sand blasting and chromic-sulphuric acid etching were also studied to compare their relative merits in making strong bonds. The nature of the adherend surface produced by these processes was examined by electron microscopy and surface profile records to determine its significance in the bonding process. Aluminium alloy 2014 (untempered) was used as the adherend material and a heat-curing, two-part structural epoxy as the adhesive. It was observed that different treatments render different bond strengths, and that variation of some process parameters in each treatment influences the joint strength with the same adhesive-adherend system. The surface profile records and electron micrographs of the treated adherends give an indication of the relative bond strengths which occur after the joints are formed. Some machining processes such as shaping, milling, and turnin...