Ultrasonic joining of carbon-reinforced polyamide with oak wood for manufacturing sustainable hybrid structures

• The joining of wood-polymer via ultrasonic energy was demonstrated. • Wood surface structuring improved the mechanical performance of the hybrid joint. • Polymer infiltrated wood surface crevices, improving mechanical interlocking. • Average ultimate lap shear strength of 9.2 ± 0.7 MPa was obtained. The feasibility of manufacturing strong and lightweight hybrid joints of carbon fiber-reinforced polyamide (PA6-15CF) and oak wood using ultrasonic energy was successfully demonstrated. Before joining, a groove pattern was generated on the surface of the wood platelets by laser texturing. Wood platelets with and without texturing were joined with the polymer using the ultrasonic joining (U-Joining) process. Mechanical interlocking at the polymer-wood interface was improved, as the grooves and open vessels on the surface of the textured wood platelets were filled with the polymer composite. Therefore, the lap-shear strength of joints with textured wood was 9.2 ± 0.7 MPa, whereas the shear strength of joints with untextured wood was just 4.1 ± 0.8 MPa.