Temperature-Dependent Mechanical Properties of Additive Manufactured Carbon Fiber Reinforced Polyethersulfone

Material extrusion additive manufacturing of thermoplastic composites have been used for rapid prototyping of tools or molds that are then used for production of structural composite parts via conventional manufacturing methods. The process utilizes short fiber reinforced polymer pellets, which allows for the printed mold to remain rigid throughout the final composite part fabrication process as well as retain some integrity. Composite parts manufactured using printed molds are usually accomplished at elevated temperatures, and high-temperature composite feedstock that are commercially available has enabled this type of application. However, mechanical data of printed parts is often limited to certain deformation modes and elevated temperature behavior is usually not reported in the literature. This work characterizes and discusses the mechanical behavior of a short fiber reinforced polyethersulfone and includes the influence of elevated temperature. Tension, compression, and shear deformations were analyzed using digital image correlation, which captured the surface strain fields for each temperature condition. The results show that stiffness generally decreases with temperature; however, certain shear deformation modes do not necessarily follow this trend. Moreover, specimens loaded under tension exhibit brittle-like behavior at elevated temperatures. These results are useful for designing printed composites using material extrusion additive manufacturing to account for changes in behavior under elevated temperature environments.