PSI - Issue 5

David Palousek et al. / Procedia Structural Integrity 5 (2017) 393–400 Vendula Kratochvilova et al. / Structural Integrity Procedia 00 (2017) 000 – 000

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Fig. 7. Comparison of AE records: (a) reference material AlCu2Mg1.5Ni before T6 (stress amplitude 275 MPa); (b) SLM material AlCu2Mg1.5Ni – 1st batch (stress amplitude 153 MPa)

Fig. 8. Comparison of AE records: (a) reference material AMPCOLOY® 644 (stress amplitude 433 MPa); (b) SLM material Cu7.2Ni1.8SiCr (stress amplitude 316 MPa)

A fractographic analysis was performed to supplement AE and fatigue measurements, see Fig. 9. The crack origins are usually located in the surface or sub-surface defects (red squares on the Fig. 9), un-melted powder grains in those defects indicates that those defects were created during production. The presence (yellow rings on the Fig. 9) of production defects on the fracture surfaces confirm the hypothesis about crack spread through the connection between them.

Fig. 9. Fracture surface of SLM material with the cracks origins: (a) AlCu2Mg1.5Ni; (b) Cu7.2Ni1.8SiCr

4. Conclusion

Fatigue tests results of additively produced materials were presented in this study. Fatigue resistance of SLM alloys AlCu2Mg1.5Ni, AlSi10Mg and Cu7.2Ni1.8SiCr and extruded materials with similar chemical composition was compared. Generally, the fatigue resistance of SLM material is worst then of extruded material. This difference is more significant in case of material AlCuMg1.5Ni.