Mechanical and ultrasonic characterization of polyamide 11-copper composites manufactured with diverse scanning strategies and energy density parameters

Selective laser sintering is a laser powder bed fusion additive manufacturing method enabling the fabrication of polymers and composites. This study aims to investigate the influence of scanning strategy and energy density on the mechanical behavior and microstructural characteristics of PA11 and dendritic copper-reinforced PA11 structures. Three distinct hatching strategies were employed, with the energy density systematically varied. A comprehensive characterization was conducted, including radiographic inspection, tensile testing, ultrasonic measurements and scanning electron microscopy analysis. The elastic modulus was determined for different orthogonal faces of cubic specimens using time-of-flight data obtained via ultrasonic measurements, and the anisotropy in their elastic properties was subsequently evaluated. Results demonstrate that tensile strength is significantly affected by the scanning strategy, with the 45/135 alternating hatching strategy yielding lower tensile strength than other strategies. In contrast, increasing energy density promotes sintering, leading to a denser microstructure, improved interparticle bonding, and, consequently, higher elastic modulus values. Furthermore, Ultrasonic evaluation demonstrates anisotropic elastic behavior that depends on both the scanning strategy and the energy density. The study contributes to a better understanding of the relationship between additive manufacturing parameters and mechanical behavior, as well as the potential application of ultrasonic measurement in material characterization.