Predictive models for fatigue property of laser powder bed fusion stainless steel 316L

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

doi:10.1016/j.matdes.2018.02.054

Cited by 71 publications

(42 citation statements)

References 47 publications

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“…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 Resistancementioning

confidence: 76%

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 Resistancementioning

confidence: 76%

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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“…Compared to the uniaxial tension used in our experiment, bending is a less severe loading condition for fatigue, therefore normally resulting in a fatigue live~50% longer than from a tension test [37]. The differences in fatigue properties may be caused by the density [16,17], which changes the tensile strength of materials [6].…”

Section: Discussionmentioning

confidence: 96%

“…It is reasonable that GA samples have much longer fatigue lives than the WA samples. Figure 12 compares the fatigue properties of the samples in this research with those prepared through conventional powder metallurgy (PM) [34] and SLM [6,35]. In order to offset the influence of different mean stresses on the fatigue life, all the stress amplitudes from different researches are normalized using the SWT equation [36]:…”

Section: Discussionmentioning

confidence: 99%

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On the Microstructures and Fatigue Behaviors of 316L Stainless Steel Metal Injection Molded with Gas- and Water-Atomized Powders

Zhang

Feng

et al. 2018

Metals

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316L stainless steel samples are fabricated by metal injection molding using water-atomized and gas-atomized powder with different oxygen contents. The influences of oxygen on the microstructural evolution and fatigue properties of the samples are investigated. The oxygen tends to react with Mn and Si to form oxide particles during sintering. The oxides hamper the densification process and result in decreased sintered density. Moreover, their existence reduces the Mn and Si dissolving into the base metal and compromises the solution strengthening effect. The oxides lead to stress concentration in the tensile and fatigue tests and become the initiation sites of fatigue cracks. After sintering, the samples made from the gas-atomized powder have a much lower oxygen content compared to those made from the water-atomized powder, therefore, exhibiting much better mechanical properties. The tensile strength, yield strength and the elongation of the samples made from the gas-atomized powder are 560 MPa, 205 MPa, and 58%, respectively. Their fatigue lives are about one order of magnitude longer than the samples made from water-atomized powder, and also longer than those fabricated by powder metallurgy and selective laser sintering which were reported in other studies.

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“…13 It is well documented that porosity can result in fatigue crack initiation. 5,10,[14][15][16][17][18][19][20] In the work presented herein, the critical size of the pores that are prone to fatigue cracks is investigated and quantified for Inconel 718 material produced by SLM.…”

Section: Introductionmentioning

confidence: 99%

ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

Sangid

Ravi

Prithivirajan

et al. 2019

JOM

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A degree of porosity is expected in additively manufactured (AM) materials. To aid in the qualification of AM materials, the smallest pore size that results in a debit in the fatigue performance is quantified. In the work presented herein, crystal plasticity simulations are used to identify the stress concentration around pores of various sizes, revealing that a single 20-lm pore or two 10-lm pores (with centers spaced 15 lm apart) localize stress at the pore, as opposed to elsewhere in the microstructure. In situ microtomography and far-field high-energy x-ray diffraction microscopy were used to identify crack formation and the evolution of the grain-level micromechanical fields during cyclic loading. Eighteen cracks were observed (15 at pores, 3 at the surface) at highly stressed grains in a sample, although most did not propagate. The dominant crack was seen to originate from the free surface, which is rationalized by fracture mechanics.

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Predictive models for fatigue property of laser powder bed fusion stainless steel 316L

Cited by 71 publications

References 47 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

On the Microstructures and Fatigue Behaviors of 316L Stainless Steel Metal Injection Molded with Gas- and Water-Atomized Powders

ICME Approach to Determining Critical Pore Size of IN718 Produced by Selective Laser Melting

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