Fatigue and fracture behaviour of laser powder bed fusion stainless steel 316L: Influence of processing parameters

Zhang, Meng; Sun, Chen-Nan; Zhang, Xiang; Goh, Phoi Chin; Wei, Jun; Hardacre, David; Li, Hua

doi:10.1016/j.msea.2017.07.071

Cited by 160 publications

(92 citation statements)

References 61 publications

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“…7) show the recalculated final maximum stress compared to the porosity amount measured in computed tomography. Most of the fatigue limits at 10 6 cycles fall between 300 and 400 MPa, which correlates well with the results of Zhang et al [12] for 316L samples tested in the identical conditions and fabricated using good SLM parameters. While results from the literature show that the porosity rate can impact fatigue properties for SLM + post-machining 316L samples with open porosities [46], no clear impact of the internal porosity rate (between 0.02% and 2.7% in volume) or defect distribution was noticed on the samples tested with various hatching but similar contour conditions.…”

Section: High Cycle Fatigue Resistancesupporting

confidence: 89%

“…5 d). From the porosity measurements and observations from the literature for similarly porous 316L samples fabricated with SLM [12], little to no variation between sets is expected in their yield strength or ultimate tensile strength. The dimensions and porosity rates extracted from 3D measurements are two to three times greater than those measured from 2D observations.…”

Section: Porosity Measurementsmentioning

confidence: 89%

“…The hatching pore size distribution of each sample set was described using the Gumbel extreme value distribution, as previously shown in Refs. [12,40]. Using the cylindrical samples, the largest pore on each optical image was measured using automatic image processing with Python, and the square root of its area was used as an input to estimate the Gumbel distribution parameters.…”

Section: Porosity Characterization Methodsmentioning

confidence: 99%

“…Surface finish has been long known to influence at the first order the fatigue properties of parts manufactured not only with traditional methods [7] but also using additive manufacturing techniques [8][9][10]. The occurrence of porosity or unmelted particles in powder bed fusion parts, especially at or near the surface, has also been shown to reduce fatigue strength [11,12]. Lastly, microstructure also plays a role on the fatigue properties, but to a lesser extent.…”

Section: Introductionmentioning

confidence: 99%

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A competition between the contour and hatching zones on the high cycle fatigue behaviour of a 316L stainless steel: Analyzed using X-ray computed tomography

Andreau

Pessard

Koutiri

et al. 2019

Materials Science and Engineering: A

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Metal powder bed fusion techniques can be used to build parts with complex internal and external geometries. Process parameters are optimized in order to obtain parts with low surface roughness and porosity, while maintaining a high productivity rate. The goal of this work is to quantify the sensitivity to internal and surface defects on the fatigue endurance of additively manufactured metallic parts. 316L Stainless Steel samples were fabricated through powder bed fusion using identical contour parameters, but three different hatching strategies were applied by varying the scanning speeds in the internal portions of the parts. Samples were subsequently mirror-polished to smooth the rough as-built surface. X-ray computed tomography analysis revealed several defect populations in samples from all three parametric sets due to lack of fusion in the bulk, with a nearly fully dense external "shell". High cycle fatigue tests at R = 0.1 were then performed on the specimens and combined with the X-ray computed tomography scans, helping to identify the largest and the critical defect size at which crack initiation occurred. Most fatigue failures initiated within the external contour zone for small (< 100 μm) defects, even when larger (> 200 μm) lack of fusion defects were widely present below the surface. It was determined that the high porosity (1% in volume or above 5% in area at some fabricated layers) observed in the bulk of parts manufactured with high scanning speeds had little impact on the fatigue limit of the material.

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Section: High Cycle Fatigue Resistancesupporting

confidence: 89%

Section: Porosity Measurementsmentioning

confidence: 89%

Section: Porosity Characterization Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A competition between the contour and hatching zones on the high cycle fatigue behaviour of a 316L stainless steel: Analyzed using X-ray computed tomography

Andreau

Pessard

Koutiri

et al. 2019

Materials Science and Engineering: A

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“…Specifically, studies done by Zhong et al [29] had shown that the cellular boundaries are enriched with molybdenum atoms and nano-sized inclusions, which could create local stress concentration and promote cracking. Details of the fatigue fracture mechanisms for as-built L-PBF stainless steel 316L could be found in the authors' prior work [30].…”

Section: Crack-initiating Defectsmentioning

confidence: 99%

Effect of heat treatment on fatigue crack initiation of laser powder bed fusion stainless steel 316L

et al. 2018

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Abstract. Laser powder bed fusion (L-PBF) is an emerging additive manufacturing technique for building structural components. L-PBF processing defects, such as lack of fusion pores, promote fatigue crack initiation and shorten the fatigue life. With well-controlled processing, critical pores can be avoided such that the microstructure-driven intergranular crack initiation mode becomes operative. In this work, the fatigue crack initiation behaviours of as-built and solution annealed L-PBF stainless steel 316L were studied. Crack initiation of the as-built samples is driven by de-bonding of the dendritic grain boundaries. High temperature annealing results in the formation of thermally-induced defects, possibly via the reheat cracking mechanism and the nucleation of pre-existing gas pores. As heat treating could have led to recrystallization and annihilation of the original grain boundary defects, the thermally-induced defects became the new sites for crack initiation. In addition, heat treatment incurred significant reduction in yield strength, such that the interaction of fatigue and ratcheting strain accumulation dominated the deformation behaviour of the material. The resulting fatigue strength in the finite life regime was reduced by about 13% but the fatigue endurance limit was not affected.

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The Influence of Powder Reuse on the Properties of Laser Powder Bed‐Fused Stainless Steel 316L: A Review

et al. 2022

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There is a clear economic benefit for the recycling of metallic powder during additive manufacturing (AM). Laser powder bed fusion (L‐PBF) is one such AM process and research has found that the properties of the powder feedstock can change when the powder is reused through mechanisms such as spatter generation and alterations in chemistry. Such changes to powder properties can accumulate and may lead to significant differences in the mechanical properties of the final component. Often the changes to part properties are reasonably small; however, there is not currently enough understanding of the specific links between powder properties and the characteristics of the end component for the effects of powder recycling to be discounted. Herein, the typical lifecycle of stainless steel 316L powder in L‐PBF, the changes that occur to the powder feedstock, and the effects that this may have on the mechanical properties of components manufactured with recycled powder are reviewed.

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Fatigue and fracture behaviour of laser powder bed fusion stainless steel 316L: Influence of processing parameters

Cited by 160 publications

References 61 publications

A competition between the contour and hatching zones on the high cycle fatigue behaviour of a 316L stainless steel: Analyzed using X-ray computed tomography

A competition between the contour and hatching zones on the high cycle fatigue behaviour of a 316L stainless steel: Analyzed using X-ray computed tomography

Effect of heat treatment on fatigue crack initiation of laser powder bed fusion stainless steel 316L

The Influence of Powder Reuse on the Properties of Laser Powder Bed‐Fused Stainless Steel 316L: A Review

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