Influence of post-processing on very high cycle fatigue resistance of Inconel 718 obtained with laser powder bed fusion

2021 ◽  
pp. 106510
Author(s):  
Chuanli Yu ◽  
Zhiyong Huang ◽  
Zian Zhang ◽  
Zhiping Xu ◽  
Jiebin Shen ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Powder Bed Fusion ◽  
Cycle Fatigue ◽  
Laser Powder Bed Fusion ◽  
Post Processing ◽  
Powder Bed ◽  
Very High Cycle Fatigue ◽  
Very High

scholarly journals Very-High-Cycle Fatigue Behavior of Inconel 718 Alloy Fabricated by Selective Laser Melting at Elevated Temperature

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1001
Author(s):  
Zongxian Song ◽  
Wenbin Gao ◽  
Dongpo Wang ◽  
Zhisheng Wu ◽  
Meifang Yan ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Selective Laser Melting ◽  
Fatigue Resistance ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Cycle Fatigue ◽  
Laser Melting ◽  
Inconel 718 Alloy ◽  
Very High Cycle Fatigue ◽  
Very High

This study investigates the very-high-cycle fatigue (VHCF) behavior at elevated temperature (650 °C) of the Inconel 718 alloy fabricated by selective laser melting (SLM). The results are compared with those of the wrought alloy. Large columnar grain with a cellular structure in the grain interior and Laves/δ phases precipitated along the grain boundaries were exhibited in the SLM alloy, while fine equiaxed grains were present in the wrought alloy. The elevated temperature had a minor effect on the fatigue resistance in the regime below 108 cycles for the SLM alloy but significantly reduced the fatigue strength in the VHCF regime above 108 cycles. Both the SLM and wrought specimens exhibited similar fatigue resistance in the fatigue life regime of fewer than 107–108 cycles at elevated temperature, and the surface initiation mechanism was dominant in both alloys. In a VHCF regime above 107–108 cycles at elevated temperature, the wrought material exhibited slightly better fatigue resistance than the SLM alloy. All fatigue cracks are initiated from the internal defects or the microstructure discontinuities. The precipitation of Laves and δ phases is examined after fatigue tests at high temperatures, and the effect of microstructure on the formation and the propagation of the microstructural small cracks is also discussed.

Mechanisms driving high-cycle fatigue life of as-built Inconel 718 processed by laser powder bed fusion

2019 ◽  
Vol 761 ◽  
pp. 137993 ◽  
Author(s):  
Dillon S. Watring ◽  
Kristen C. Carter ◽  
Dustin Crouse ◽  
Bart Raeymaekers ◽  
Ashley D. Spear
Keyword(s):  
Fatigue Life ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Powder Bed Fusion ◽  
Cycle Fatigue ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals High cycle fatigue life estimation of AlSi10Mg processed by laser powder bed fusion

2018 ◽  
Vol 188 ◽  
pp. 03015 ◽  
Author(s):  
Even W. Hovig ◽  
Amin S. Azar ◽  
Martin F. Sunding ◽  
Knut Sørby ◽  
Mohammed M'hamdi ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Surface Properties ◽  
High Cycle Fatigue ◽  
Material Surface ◽  
Powder Bed Fusion ◽  
Cycle Fatigue ◽  
Laser Powder Bed Fusion ◽  
Element Analysis ◽  
Powder Bed

Fatigue life is known to be dependent on the surface properties of the material. Surface roughness provokes local stress concentration and cause crack initiation even at minute cyclic loads. In laser powder bed fusion, the as-built surfaces show variable roughness depending on the orientation of the specimens with respect to the build plate. In order to analyse the effect of build angle on surface properties, flat tensile specimens were produced from an AlSi10Mg alloy in a Concept Laser M2 Cusing machine. Seven specimens were arranged from flat to perpendicular with respect to the build plate at 15° intervals. The as-built surface topography of each specimen was characterised by white light interferometry. Two methods for calculating the stress concentration factor for high cycle fatigue simulation were developed. The presence of subsurface porosity was a crucial factor in expanding the stress concentration as demonstrated by finite element analysis.

scholarly journals Very High Cycle Fatigue Investigations on the Fatigue Strength of Additive Manufactured and Conventionally Wrought Inconel 718 at 873 K

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1682
Author(s):  
Alexander Schmiedel ◽  
Christina Burkhardt ◽  
Sebastian Henkel ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
Crack Initiation ◽  
Inconel 718 ◽  
High Cycle Fatigue ◽  
Fatigue Testing ◽  
Reference Conditions ◽  
Cycle Fatigue ◽  
Very High Cycle Fatigue ◽  
Ultrasonic Fatigue ◽  
Fine Grained Structure ◽  
Very High

The fatigue lives of additively manufactured (AM) Inconel 718 (IN718) produced by selective electron beam melting and conventional wrought material as reference conditions were studied in the very high cycle fatigue regime under fully reversed loading (R = −1) at the elevated temperature of 873 K using an ultrasonic fatigue testing system. The fatigue lives of the AM material were significantly reduced compared to the wrought material, which is discussed in relation to the microstructure and a fractographical analysis. The additively manufactured material showed large columnar grains with a favoured orientation to the building direction and porosity, whereas the wrought material showed a fine-grained structure with no significant texture, but had Nb- and Ti-rich non-metallic inclusions. Crystallographic crack initiation as well as crack initiation from the surface or internal defects were observed for the AM and the wrought IN718, respectively.

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