Additive manufacturing (AM) enables the production of parts with high geometric complexity including internal structures, leading to increasing interest of science and industry in recent years [1]. The mechanical properties of additively manufactured components, however, are still not completely understood and subject of intensive research efforts [2]. In particular, residual stresses (RS) play an important role for the strength and fatigue properties. Therefore, RS distributions were investigated in various parts, fabricated from aluminium alloy powder (AlSi10Mg) using the Laser Powder Bed Fusion (LPBF) technique.

Residual stress fields in parts with different geometries, produced with the alloy AlSi10Mg, were determined using high-energy X-ray diffraction using the high-energy Hereon beamlines (P07 and P61A) at PETRA III at Deutsches Elektronen Synchrotron (DESY). Angle-dispersive diffraction was used in transmission geometry and energy-dispersive techniques were used to obtain three-dimensional spatial resolution.

AM has a variety of process parameters. To improve the RS state and surface quality, the geometry and contour have to be taken into account. The geometry creates zones with heat concentration, and the contour of each individual layer can be heat treated during construction, which induces a change in the RS state. The manipulation of residual stresses achieved by the contour treatment (Figure 1) was observed in various geometries. The influence of the contour parameter at different positions of different sample geometries is presented and the potential for improving the production process will be pointed out.

References

[1] Yang, L., et al., Additive manufacturing of metals: the technology, materials, design and production. 2017: Springer.

[2] Campbell, I., et al., Wohlers report 2018: 3D printing and additive manufacturing state of the industry: annual worldwide progress report. 2018: Wohlers Associates.

Dr. Marc-André Nielsen