Computed tomography for characterization of fatigue performance of selective laser melted parts

Siddique, Shafaqat; Imran, Muhammad�; Rauer, Miriam; Kaloudis, Michael; Wycisk, Eric; Emmelmann, Claus; Walther, Frank

doi:10.1016/j.matdes.2015.06.063

Cited by 185 publications

(99 citation statements)

References 28 publications

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“…Two aluminum alloys, AlSi10Mg and AlSi12, were investigated with platform heating as the main factor. The latter factor is identified in the previous literature as a control parameter to reduce remnant porosity and coarsen microstructure [10,11]. In this study, it was found consistent that platform heating improved ductility, but tensile strength was not reduced in AlSi10Mg alloy.…”

Section: Discussionsupporting

confidence: 61%

“…It is observable that batch A developed defects of bigger volume than batch B while in the latter the smaller diameter porosity (< 120 µm) was more. The relationship between stress developed by porosity and their size was described in detail in [10]. The latter identified pore diameter and location as the most influential factors.…”

Section: Experimental Testingmentioning

confidence: 99%

“…The analysis introduced stressconcentration factors for pores as a function of diameter and proximity to the surface. Given this, HIP of AlSi12 was assumed to enhance fatigue strength, but due to microstructure alteration and Si agglomeration, fatigue strength was significantly reduced [10]. Nevertheless, the fatigue strength of SLM AlSi12 in as-built condition was superior to cast alloy.…”

Section: Introductionmentioning

confidence: 99%

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Qualification of selective laser-melted Al alloys against fatigue damage by means of measurement and modeling techniques

et al. 2018

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Abstract. Aluminum alloys processed through selective laser melting possess unique features of microstructure, defect morphology and mechanical properties. Constitution of fine cellular dendrites results from the high-cooling rate of the melt pool during the consolidation process. Investigation of the microstructure by scanning electron microscopy identifies supersaturation of Si particles as a secondary strengthening mechanism. On the contrary, platform heating that induces coarser microstructure leads to migration of Si particles from the Al matrix to the eutectic phase. As a result, tensile strength is reduced by 3%, while fracture strain is increased by 17%. Fine-grained structures exhibit a lower amount of plastic damage accumulation as well as delayed crack initiation as determined by the applied measurement techniques. Finite element models of the investigated configurations are obtained using scans of computed tomography under consideration of process-induced defects. Comparison of modeling and experimental results concluded that dominant fatigue damage mechanisms are related to the loading regime from low-cycle (LCF) to very-high-cycle fatigue (VHCF). Thus, process-inherent features of microstructure and porosity have different quantitative effects concerning the applied load. In VHCF, a material configuration with platform heating possesses an improved fatigue strength by 33% at 1E9 cycles, concerning the material configuration without platform heating.

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Section: Discussionsupporting

confidence: 61%

Section: Experimental Testingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Qualification of selective laser-melted Al alloys against fatigue damage by means of measurement and modeling techniques

et al. 2018

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“…The SCF increases for larger pores close to the groove tip, while it decreases if the pore diameter is reduced or the pore is moved further away from the groove tip. Siddique et al [11] expressed the SCF of a pore as a function of the pore diameter and distance from the surface (no surface roughness), with values for k t ranging from 1 to 1.178. When comparing the magnitude of the stress concentration from only surface defects (Eq.…”

Section: Figure 3 Optical Microscopy Image Of a Cross Section Of The mentioning

confidence: 99%

“…The effective SCF is then the SCF of the pore. Since the SCFs of pores are in the range of 1 to 1.178 [11], further crack propagation will be slowed down. Although sub-surface porosity might be present, it is unlikely it will be regularly distributed below the surface to blunt all cracks propagating.…”

Section: Figure 3 Optical Microscopy Image Of a Cross Section Of The mentioning

confidence: 99%

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

et al. 2018

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Abstract.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.

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Review on Fatigue of Additive Manufactured Metallic Alloys: Microstructure, Performance, Enhancement, and Assessment Methods

Liu,

Yu,

Guo

et al. 2023

Advanced Materials

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Additive manufacturing (AM), which is a process of building objects in a layer‐upon‐layer fashion from designed models, has received unprecedented attention from research and industry because it offers outstanding merits of flexibility, customization, reduced buy‐to‐fly ratio, and cost‐effectiveness. However, the fatigue performance of safety‐critical industrial components fabricated by AM is still far below that obtained from conventional methods. This review discusses the microstructural heterogeneities, randomly dispersed defects, poor surface quality, and complex residual stress generated during the AM process that can negatively impact the fatigue performance of as‐printed parts. The difference in microstructural origin of fatigue failure between conventionally manufactured and printed metals is reviewed with particular attention to the effects of the trans‐scale microstructures on AM fatigue failure mechanisms. Various methods for mitigating the fatigue issue, including pre‐process, inter‐process and post‐process treatments, are illustrated. Empirical, semi‐empirical and microstructure‐sensitive models are presented to predict fatigue strength and lifetime. Summary and outlooks for future development of the fatigue performance of AM materials are provided.This article is protected by copyright. All rights reserved

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Computed tomography for characterization of fatigue performance of selective laser melted parts

Cited by 185 publications

References 28 publications

Qualification of selective laser-melted Al alloys against fatigue damage by means of measurement and modeling techniques

Qualification of selective laser-melted Al alloys against fatigue damage by means of measurement and modeling techniques

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

Review on Fatigue of Additive Manufactured Metallic Alloys: Microstructure, Performance, Enhancement, and Assessment Methods

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