On the effect of internal channels and surface roughness on the high-cycle fatigue performance of Ti-6Al-4V processed by SLM

Günther, Johannes; Leuders, Stefan; Koppa, Peter; Tröster, Thomas; Henkel, Sebastian; Biermann, Horst; Niendorf, Т.

doi:10.1016/j.matdes.2018.01.042

Cited by 103 publications

(53 citation statements)

References 43 publications

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“…However, it is time consuming [27], and increases the global cost of additively manufactured parts. Moreover, machining cannot be applied on complex lattice parts or for thin internal features such as thin channels [28]. Other post-processing solutions have been investigated, such as chemical or electrochemical polishing [29,30], shot peening [31], and sand blasting [32].…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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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“…Based on previous works, the Poisson coefficient of Ti-6Al-4V produced by PBF is found to be 0.32 [25] and 0.324 [27] which summarizes at an average of ν = 0.322. Similarly, the Young Modulus of HIPped Ti-6Al-4V produced by means of PBF is found to be 115.4 GPa [3] and 114 GPa [5], which for this work is averaged toĒ = 114.7 GPa.…”

Section: B Production Process and Materials Propertiesmentioning

confidence: 60%

Analytical Modeling of Embedded Load Sensing Using Liquid-Filled Capillaries Integrated by Metal Additive Manufacturing

et al. 2019

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Additive manufacturing (AM) offers new manufacturing solutions for the integration of smart functionalities in engineering structures. In this paper, an analytical model is presented for an embedded load sensing element based on a liquid-filled capillary. During the additive manufacturing process, the capillary is integrated in the region where the strain is to be determined. The embedded capillary deforms as the structure deforms under an applied load, as such altering the pressure inside the capillary. The monitoring of the capillary pressure allows monitoring the loads and thus usage of the component. This paper presents a model describing the behavior of the sensing element under uniform tensile stress. The sensitivity of the load sensing element per unit longitudinal strain depends on the bulk modulus of the liquid inside the capillary and the Poisson coefficient of the surrounding material. The current work further compares the analytical model against static tension-compression tests of powder bed fused stainless steel (AISI 316L) test specimen with an integrated capillary filled with a liquid (water). Similarly, the validation of the model is then checked against a dynamic four-point bending test on a Ti-6Al-4V specimen produced by powder bed fusion.

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“…Several commercially available implants utilise designed porosity, such as acetabular cups, and whilst bearing surfaces are machined smooth, removal of remnant powder from the porous surface is a key consideration. Ultrasonic cleaning is often raised as an option, however may be insufficient to remove all remnant particulate matter [245], and will do little to remove surface defects common to AM parts that reduce fatigue strength [246].…”

Section: Surface Processingmentioning

confidence: 99%

Clinical, industrial, and research perspectives on powder bed fusion additively manufactured metal implants

Lowther

Louth

Davey

et al. 2019

Additive Manufacturing

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A B S T R A C TFor over ten years, metallic skeletal endoprostheses have been produced in select cases by additive manufacturing (AM) and increasing awareness is driving demand for wider access to the technology. This review brings together key stakeholder perspectives on the translation of AM research; clinical application, ongoing research in the field of powder bed fusion, and the current regulatory framework. The current clinical use of AM is assessed, both on a mass-manufactured scale and bespoke application for patient specific implants. To illuminate the benefits to clinicians, a case study on the provision of custom cranioplasty is provided based on prosthetist testimony. Current progress in research is discussed, with immediate gains to be made through increased design freedom described at both meso-and macro-scale, as well as long-term goals in alloy development including bioactive materials. In all cases, focus is given to specific clinical challenges such as stress shielding and osseointegration. Outstanding challenges in industrialisation of AM are openly raised, with possible solutions assessed. Finally, overarching context is given with a review of the regulatory framework involved in translating AM implants, with particular emphasis placed on customisation within an orthopaedic remit. A viable future for AM of metal implants is presented, and it is suggested that continuing collaboration between all stakeholders will enable acceleration of the translation process. fection or surgical complications [11][12][13].Currently, the majority of skeletal endoprostheses are produced from titanium (Ti) or cobalt chromium (CoCr) based alloys, which meet the criteria of durability, strength, corrosion resistance and a low immune response [14,15]. These characteristics however come at the cost of the high stiffness of these alloys in comparison to bone. Mismatch between the mechanical properties of bone and orthopaedic materials

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On the effect of internal channels and surface roughness on the high-cycle fatigue performance of Ti-6Al-4V processed by SLM

Cited by 103 publications

References 43 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

Analytical Modeling of Embedded Load Sensing Using Liquid-Filled Capillaries Integrated by Metal Additive Manufacturing

Clinical, industrial, and research perspectives on powder bed fusion additively manufactured metal implants

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