Strength and failure patterns of metal–metal adhesives

Abstract

Torsional shear napkin-ring test-pieces have been used in adhesion studies with two titanium alloys, modified epoxy and epoxy-phenolic adhesives. The temperature profiles have been obtained and the failure surfaces studied. The metallography of the surfaces is recorded and the effect of a variety of preparative surface treatments. Most treatments lead to rutile, and in one case rutile needles bond to the adhesive more strongly than to the substrate. Surface roughness is shown to enhance bond strength.