Selective laser sintering mechanical properties study of polyamide 12/glass fiber composites

The effect of variation of glass fiber(GF) content on the mechanical properties of the fabricated polyamide 12 (PA12)/GF composites was investigated based on the selected laser sintering process. Firstly, PA12/GF composites with different GF mass fractions(10%-30%) were prepared. Then, based on mechanical property testing and microstructure characterization, the influence of GF mass fraction on the mechanical properties and interfacial microscopic characteristics of sintered parts was systematically analyzed. The results show that at the same process parameters(scanning speed of 5 000 mm/s, laser power of 37.7 W, scan pitch of 0.12 mm), the bending strength increases continuously with the increase of GF mass fraction, the tensile strength increases and then decreases, while the impact toughness shows a monotonic decreasing trend. The overall mechanical properties of the sintered parts with GF mass fraction of 10% are optimal, with tensile and flexural strengths of 48.65 MPa and 53.54 MPa, respectively, which are 2.6% and 12.0% higher than those of pure PA12, while the impact toughness is slightly lower at 64.01 kJ/m2. The fiber pull-out becomes main mechanism of PA12/GF interface damage when the GF mass fraction is high, and this mechanism leads to a reduction in impact toughness, which is consistent with the mechanical properties impact toughness test results. The addition of 10% GF helps to enhance the crystallinity of the material, making the sintered specimens possess the characteristics of the GF reinforced phase while retaining the advantages of the polyamide matrix phase, and taking advantage of both the polyamide matrix phase and the GF reinforced phase, thus presenting good comprehensive mechanical properties. © 2023 Central South University of Technology. All rights reserved.