PLA-based additively manufactured samples with different infill percentages under freeze-thaw cycles; mechanical, cracking, and microstructure characteristics

• Published in: Theoretical and applied mechanics letters 2024-11, Vol.14 (6), p.100536, Article 100536
• Main Authors: Ale Ali, Reza, Karimi, Hamid Reza, Mohamadi, Razie
• Format: Article
• Language: English
• Subjects: 3D print; Fracture; Freeze-thaw; Mechanical behavior; Microstructure
• ISSN: 2095-0349
• DOI: 10.1016/j.taml.2024.100536

•PLA-based samples had different densities and were tested under 4, 8, and 12 freeze-thaw cycles.•Tensile, mode-I fracture, and flexural tests were done along with microstructure evaluation.•With a decrease in infill percentage, the effect of freeze-thaw becomes more significant.•The common range of decrease in strength due to 12 cycles was 25 to 45%.•SEM shows the cracking in links, breakage of joints, and flaking due to cycles. The layered nature of the parts produced by 3D printing makes them susceptible to freeze-thaw damage. This research investigates the effect of the freeze-thaw cycles on the tensile, bending, and fracture resistance of samples made of Polylactic acid material. For this purpose, the samples with 100, 75, 50, and 25 infill percentages were subjected to 4, 8, and 12 freeze-thaw cycles. The results show that the infill percentage and cycle affect freeze-thaw resistance. So, although for 100% infill samples, the 4, 8, and 12 cycles averagely reduce the tensile strength by 5, 15, and 25. The same trends can also be seen for flexural strength and, more severely, fracture resistance. Reviewing the microstructure with a Scanning electron microscopy device shows freeze-thaw's destructive effect (both the strand's surface and their joints). In the end, simple statistical analyses were presented to evaluate a model for anticipating the effect of freeze-thaw on mechanical resistance. [Display omitted]