PSI - Issue 54

Martin Matušů et al. / Procedia Structural Integrity 54 (2024) 135 – 142 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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On the other hand, however, if the pairs of identical HTs across different platforms are analysed, no significant effect observed in the shape and position of the S-N curves can be easily detected in the thermal response. If, e.g., the T300 case is treated, the higher positioned fatigue limit of the specimens from platform n°3 could be related to lower thermal response below 80 MPa compared to the platform n°5. The very similar low-cycle fatigue response observed by both S-N curves could also be detected in the thermal response at higher load levels. But then there is the case of T200 HT, where the fatigue curve related to platform n°4 is significantly below the curve related to platform n°3, its self-heating curve shown in Figure 6 is below the results of platform n°4, however. This means that the likely more defective microstructure of specimen’s platform n°4 results in less heat generated during the same load level. Though such observations are contradicting our expectations, the analysis of the thermal response within the experimental campaign continues while observing also other measurable parameters [6; 8; 10].

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Fig. 5. a) The temperature evolution during constant-amplitude cyclic loading leading to failure at N f can be divided into three distinct phases. b) Step-test with various load amplitudes with the focus on stabilized temperature.

Fig. 6. Comparison of stabilized temperatures of various heat treatments and printing platforms with multiple levels of stress amplitude.

4. Conclusion Main focus of this paper is to find out if there is any fatigue performance decrease related to the repeated sifting of printing powder. Obtained results show that fatigue performance declines subsequently with each recycling step even if a two thirds of fresh powder was added for platform n°5, which seems to prove the defects within the recycled