High-strength of additive-manufactured PEEK and Ti6Al4V structure via warm isostatic pressing: applications in medical implants and injection moulds

Abstract

Polymer-metal hybrid structures offer synergistic benefits in mechanical property control and lightweight design, making them valuable across various industries. In this study, we designed and developed a warm isostatic pressing (WIP) to fabricate a hybrid structure using additive-manufactured polyetheretherketone (PEEK) and Ti-6Al-4V (Ti64) with an octet-truss lattice structure (OT). The effects of the WIP temperature on the mechanical properties of PEEK were examined by subjecting the parts to different temperatures during the WIP and performing tensile tests. Additionally, to confirm the mechanical properties of Ti64 with OT, we performed a compression test according to the unit cell size (1, 2, 3 mm) at a density of 30% before and after the WIP. Accordingly, we joined a PEEK with superior tensile strength and Ti64 with OT using a WIP under the condition (330 degrees C and 90 bar). Furthermore, we confirmed the superior joint strength of approximately 71.6-74.8% in terms of the tensile and shear strengths of the PEEK-Ti64 hybrid structures compared to the warm isostatic pressed PEEK. Finally, we demonstrated the feasibility of applying PEEK-Ti64 hybrid structures to biomedical implants such as spinal cages and lightweight injection moulds highlighting the potential in advanced manufacturing.