Fatigue Resistance of Alloy 625 Sheet

Grubb, John F.

doi:10.7449/1997/superalloys_1997_629_637

Cited by 2 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There has been only limited investigation into the fatigue life, crack propagation, and fracture toughness of additively manufactured alloy 625 [4,28,29]. It was reported that the fatigue life of the cast and additively manufactured parts is significantly lower compared to the wrought material [30]. While this report did not demonstrate the root cause of the lower performance, a different investigation into Ti-6Al-4V [31] demonstrated four key factors for fatigue performance: (1) residual stress, (2) microstructure, (3) porosity, and (4) surface finish.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterizing surface finish and fatigue behavior in binder-jet 3D-printed nickel-based superalloy 625

Mostafaei

Neelapu

Kisailus

et al. 2018

Additive Manufacturing

View full text Add to dashboard Cite

In this study, the fatigue properties of binder-jet 3D-printed nickel-base superalloy 625 were evaluated. Standard fatigue specimens were printed and sintered, then half of the samples were mechanically ground, while the other half were left in their as-sintered state. They were then characterized using micro-computed x-ray tomography, metallographic sample examination, and optical and stylus profilometry for surface topography. The micro-computed tomography observations showed that density of the as-printed sample was ~50%, while the sintered sample neared full densification (98.9 ± 0.3%) upon sintering at 1285 °C for 4 h in a vacuum atmosphere. The metallographic examination showed equiaxed grains. The roughness of the as-sintered samples was significant with an RMS roughness of Rq = 1.39 ± 0.20 μm as measured over a linescan of 5 mm, but this was reduced to Rq = 0.47 ± 0.02 μm after mechanical grinding. All samples were tested to failure in fatigue, under fully-reversed tension-compression conditions. While the as-sintered samples showed poor fatigue properties compared to prior reports on cast and milled parts, the ground samples showed superior performance. Scanning electron microscopy observation was conducted on the fractured surfaces and showed that the samples underwent transgranular crack initiation, followed by intergranular crack growth and final failure. In the mechanically ground sample, hardness increased nearly twofold up to 75 µm beneath the sample's surface and X-ray diffraction indicated an in-plane compressive stress, grain refinement, and micro-strain on the mechanically ground sample. The reduced roughness, surface hardening, and compressive stress resulted in increased fatigue life of the binder-jetted alloy 625.

show abstract

Section: Introductionmentioning

confidence: 99%

“…The fatigue behavior of cast alloy 625 has been summarized in Refs. [4,30]. Despite some investigation into the fusion processes of metallic materials, there is little information on the fatigue behavior of BJ3DP parts made from metallic materials.…”

Section: Introductionmentioning

confidence: 99%