PSI - Issue 42

Aditya Pandey et al. / Procedia Structural Integrity 42 (2022) 1017–1024 Pandey et al. / Structural Integrity Procedia 00 (2019) 000–000

1023

7

(e)

Fig. 8. (a-d) FE simulation laser track evolution, (e) melt pool comparison

Table 4. Comparison of experimental and FE model results.

Melt-pool depth ( µ m) Melt-pool width ( µ m) Hatch space ( µ m)

Experiment FE Model

50 ± 10 45 ± 10

155 ± 10 161 ± 10

105 ± 10 109 ± 10

Error

± 5

± 6

± 4

4. Conclusions

In this work, IN718 alloy specimens were printed using SLM-AM process. The mechanical behavior and fatigue performance were investigated. A FE model was developed to analyze the melt pool dimensions of the SLM process. Based on the observed results, following conclusions can be made:

• Tensile properties of heat-treated samples were slightly higher than that of as-printed samples but reduced the ductility significantly. • The fatigue lives of heat-treated samples were higher than the as-built samples. • The improved tensile and fatigue strength was attributed to the partial relaxation the residual stresses and the evolution of the strengthening phases of γ ’ and γ ”. • Fractography of broken samples revealed surface crack initiation except few cases, where crack initiated from the sub-surface defects as un-melted powder particles. • A Finite element model was developed to investigate the evolution of melt pool dimensions and the numerically obtained results show good agreement with the experimentally measured values but within a reasonable error range of ± 6 µ m.

Acknowledgements

The authors acknowledge the financial support provided by Department of Science and Technology – Science and Engineering Research Board (SERB) through the SRG scheme and the IIT Roorkee for providing necessary infrastructure to carry out the research work.