Effect of a Temperature on the Mechanical Characteristics of ULTEM 9085 Thermoplastic Produced by Additive Technology

Abstract

Results of experimental investigation of mechanical characteristics of ULTEM 9085 thermoplastic, produced by additive manufacturing, i.e., the method of layer-by-layer application of a molten polymer thread, are presented. Flat specimens were tensile tested within the temperature range of (–40) –150°C. Temperature dependencies of ultimate strength, relative elongation at break, elastic modulus, and Poisson’s ratio are obtained. At a temperature of –40°C, the linear sections of diagrams obtained for various specimens coincide; in the area of elastoplastic deformations, their discrepancy is noted. This caused small variations in elastic characteristics and significant ones in strength and relative elongation at break. Similar features of deformation diagrams were also obtained at a temperature of 50°C. However, at 150°C, tensile diagrams do not coincide even in the area of small elastic deformations; their specific bends are noted. Specimens are fractured by the normal separation mechanism at all temperatures. When the temperature changes from –40 to 150°C, thermoplastic ultimate strength almost linearly decreases; at 150°C it is 26% of the initial value at –40 °C. As temperature increases within the specified range, the relative elongation at break monotonously decreases more than twice (2.9–1.3%). The elastic modulus changes insignificantly within a temperature range of (–40)–20°C; when the temperature rises to 150°C, it decreases to 64% of the value at –40 °C. Poisson’s ratio virtually does not change and is in the range of 0.36–0.37.