Comprehensive investigation of the mechanical performance of the direct transition functional graded materials

Purpose This study aims to investigate the tensile and flexural strength of composite parts produced by joining different materials in a butt joint using additive manufacturing. Design/methodology/approach International Organization for Standardization standards were used for the specimen designs, and Fused Deposition Modeling was used for sample production. Pure polylactic acid (PLA), pure polyethylene terephthalate glycol (PETG) and PLA–wood composite were used as research materials, and six combinations were created. Pure material combinations were used for references. Tensile and three-point bending tests were performed to detect mechanical strengths. Findings As a result of the study, it was seen that pure PLA was the strongest combination in both tensile and three-point bending tests. The weakest adhesion occurred between PETG and PLA–wood composite, almost a tenth of pure PLA in both tensile and three-point bending strengths. The strongest adhesion occurred between PLA and PLA–wood composite. Originality/value This study contributes significantly to the literature by examining the direct transition of different materials in Functional Graded Materials using additive manufacturing. In particular, the application of both tensile and three-point bending tests provided valuable information regarding adhesion strength. In addition, this study contributed to the literature via wood-reinforced PLA biocomposite and used high printing speed (250 mm/s) for the production of functionally graded materials.