Additive Manufacturing of Titanium with Different Surface Structures for Adhesive Bonding and Thermal Direct Joining with Fiber-Reinforced Polyether-Ether-Ketone (PEEK) for Lightweight Design Applications

Abstract

Hybrid joints consisting of metals and fiber-reinforced polymer composites exhibit highly desirable properties for many lightweight design applications. This study investigates the potential of additively manufactured surface structures for enhancing the bond strength of such joints in comparison to face milled and laser structured surfaces. Titanium samples with different surface structures (as-built surface, groove-, and pin-shaped structures) were manufactured via electron beam melting and joined to carbon fiber-reinforced polyether-ether-ketone (PEEK) via adhesive bonding and thermal direct joining, respectively. Bond strength was evaluated by tensile shear testing. Samples were exposed to salt spray testing for 1000 h for studying bond stability under harsh environmental conditions. The initial tensile shear strengths of the additively manufactured samples were competitive to or in some cases even exceeded the values achieved with laser surface structuring for both investigated joining methods. The most promising results were found for pin-shaped surface structures. However, the hybrid joints with additively manufactured structures tended to be more susceptible to degradation during salt spray exposure. It is concluded that additively manufactured structures can be a viable alternative to laser surface structuring for both adhesive bonding and thermal direct joining of metal-polymer hybrid joints, thus opening up new potentials in lightweight design.

The Use of CFRP for Structural Reinforcement—Literature Review

“…At the same time, these hybrid structures can also improve energy absorption compared to their individual components [146]. This paper [147] presents additive manufacturing of titanium with different surface structures for adhesive bonding and direct thermal bonding with fiber-reinforced polyether-etherketone (PEEK) for lightweight structural applications. One paper [148] presents an analytical and experimental study of pre-stressed CFRP in steel structures of water locks.…”

The Effect of Surface Substrate Treatments on the Bonding Strength of Aluminium Inserts with Glass-Reinforced Poly(phenylene) Sulphide

“…Moreover, the plastic/metal combination requires specific conditions to reach optimum mechanical performance. Various studies have investigated the joining of polymer–metal bi-components with polymers such as polyether-ether-ketone (PEEK), polypropylene, and thermoplastic polyurethane [ 8 , 10 , 13 , 14 ]. There is a broad range of metal–plastic combinations and various possibilities for surface treatments; the present study only focused on evaluating the influence of selected chemical and physical treatments of aluminium inserts, concentrating on the shear bonding strength achieved during injection over-moulding with glass-fibre-reinforced PPS.…”

Covalent Grafting of Alkyl Chains on Laser-Treated Titanium Surfaces Through Silanization and Phosphonation Reactions

“…The organic layers covalently bonded to the laser-oxidized titanium surface can enhance the adhesion in titanium/polymer joints currently finding many novel applications in microelectronics [23], microfluidics [24], aerospace [25] and automotive lightweight design [26,27] and so on. As polymers and metals have very different physical properties, their bonding is usually based on the mechanical interlocking, when a melted polymer solidifies in the micrometric pattern previously created on the metallic surface [16].…”