Joining stainless steel metal foams

Abstract

Metallic foams produced from stainless steel are one of the most recently developed ultralightweight materials. These foams have very low densities and high energy absorption capacities and are therefore expected to have widespread applications in the manufacture of ultralightweight structural components. The fabrication of load bearing structural components such as implants, and high temperature air or fluid filters, are potential application areas depending on the form of the cell structure of the foam. Closed cell metal foams are typically suitable for structural uses whereas open cell foams tend to be preferred for functional applications. Development of adequate joining technologies for these materials is an essential step for their widespread industrial utilisation. The present paper describes a brazing method that is capable of providing excellent joints between 316 stainless steel foams and a conventional 316 stainless steel bulk alloy. Having optimised the bonding conditions and using a Cu–Ti alloy as the filler metal, bonds between a foam and a bulk alloy were produced. No apparent plastic deformation of the metal foam occurred in the course of the 10 min length brazing process, and the resulting bonds had tensile strengths higher than that of the stainless steel foam.