Continuous and pulsed selective laser melting of Ti6Al4V lattice structures: Effect of post-processing on microstructural anisotropy and fatigue behaviour

Karami, K.; Blok, Anne-Nynke; Weber, Ludger; Ahmadi, S.M.; Petrov, Roumen; Nikolic, Ksenija; Борисов, Е. В.; Leeflang, M.A.; Ayas, Can; Zadpoor, Amir A.; Mehdipour, Mehrad; Reinton, Elise; Popovich, Vera

doi:10.1016/j.addma.2020.101433

Cited by 41 publications

(35 citation statements)

References 60 publications

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“…For this reason, their distribution and size depend on the scanning strategy [ 211 , 213 , 214 ]. De facto, some authors showed that their thickness size is in agreement with the width of the laser scan tracks [ 59 , 213 ], while the α′ martensite thickness is between 0.5 and 3 μm [ 215 , 216 ]. The main causes of this grains size variation are correlated firstly with the selection of different process parameters, which vary the ED and the heat transfer, and, secondly, with the temperature of the BP.…”

Section: L-pbfed Ti6al4v: Microstructurementioning

confidence: 81%

Additive Manufacturing of AlSi10Mg and Ti6Al4V Lightweight Alloys via Laser Powder Bed Fusion: A Review of Heat Treatments Effects

Ghio

Cerri

2022

Materials

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Laser powder bed fusion (L-PBF) is an additive manufacturing technology that is gaining increasing interest in aerospace, automotive and biomedical applications due to the possibility of processing lightweight alloys such as AlSi10Mg and Ti6Al4V. Both these alloys have microstructures and mechanical properties that are strictly related to the type of heat treatment applied after the L-PBF process. The present review aimed to summarize the state of the art in terms of the microstructural morphology and consequent mechanical performance of these materials after different heat treatments. While optimization of the post-process heat treatment is key to obtaining excellent mechanical properties, the first requirement is to manufacture high quality and fully dense samples. Therefore, effects induced by the L-PBF process parameters and build platform temperatures were also summarized. In addition, effects induced by stress relief, annealing, solution, artificial and direct aging, hot isostatic pressing, and mixed heat treatments were reviewed for AlSi10Mg and Ti6AlV samples, highlighting variations in microstructure and corrosion resistance and consequent fracture mechanisms.

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Section: L-pbfed Ti6al4v: Microstructurementioning

confidence: 81%

Additive Manufacturing of AlSi10Mg and Ti6Al4V Lightweight Alloys via Laser Powder Bed Fusion: A Review of Heat Treatments Effects

Ghio

Cerri

2022

Materials

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“…Nevertheless, it is common to consider the failure of a specimen when it loses most or all of its stiffness 23 , 25 – 27 , e.g. 90% of stiffness reduction, or permanent displacement drops 21 , 22 , 28 . These criteria imply the loss of the load carrying capacity of the specimen, yet in the case of parts integrating lattices for load bearing applications, the changes in stiffness or deformations on the lattice might lead to the increase of stresses in the part.…”

Section: Introductionmentioning

confidence: 99%

Influence of relative density on quasi-static and fatigue failure of lattice structures in Ti6Al4V produced by laser powder bed fusion

Alaña

Cutolo

Galarreta

et al. 2021

Sci Rep

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Lattice structures produced by additive manufacturing have been increasingly studied in recent years due to their potential to tailor prescribed mechanical properties. Their mechanical performances are influenced by several factors such as unit cell topology, parent material and relative density. In this study, static and dynamic behaviors of Ti6Al4V lattice structures were analyzed focusing on the criteria used to define the failure of lattices. A modified face-centered cubic (FCCm) lattice structure was designed to avoid the manufacturing problems that arise in the production of horizontal struts by laser powder bed fusion. The Gibson–Ashby curves of the FCCm lattice were obtained and it was found that relative density not only affects stiffness and strength of the structures, but also has important implications on the assumption of macroscopic yield criterion. Regarding fatigue properties, a stiffness based criterion was analyzed to improve the assessment of lattice structure failure in load bearing applications, and the influence of relative density on the stiffness evolution was studied. Apart from common normalization of S–N curves, a more accurate fatigue failure surface was developed, which is also compatible with stiffness based failure criteria. Finally, the effect of hot isostatic pressing in FCCm structures was also studied.

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“…Compared with the sample heat-treated under vacuum, the ductility and fatigue resistance of the sample heat-treated under hot isostatic pressing improves greatly. K. Karamia et al [ 16 ] investigated the effects of optimal way of combination for sand blasting, thermal isostatic pressure and chemical etching on the mechanical and fatigue properties of Ti6Al4V and found that the combination of sand blasting and thermal isostatic pressure and chemical etching improved the fatigue behavior of Ti6Al4V the most. Although the above conventional post-treatment methods have a certain effect on the improvement of mechanical properties of parts, they are insignificant compared to the microstructural optimization and the improvement of mechanical properties for materials caused by changing SLM process parameters [ 17 ] and are not direct and economical.…”

Section: Introductionmentioning

confidence: 99%

Multi-Perspective Analysis of Building Orientation Effects on Microstructure, Mechanical and Surface Properties of SLM Ti6Al4V with Specific Geometry

Cai

Song

et al. 2021

Materials

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Building orientation is important in selective laser melting (SLM) processes. Current studies only focus on the horizontal and vertical building orientations without considering different modes of horizontal orientations. In fact, for horizontal orientation, different surfaces of the sample that contact the substrate will affect the heat transfer mode and efficiency, and in turn affect the microstructure and material properties. In this paper, the effect of two modes of horizontal building orientations on microstructure, mechanical and surface properties of SLM Ti6Al4V was studied. Current research about building orientation is deficient because the geometry of samples or test surfaces are not strictly defined, which seriously influences the results due to their different heat transfer efficiency and mode. Therefore, the geometry of the samples and test surfaces were clearly defined, and its necessity was proved in this study. To achieve the research goal, three test samples were prepared: sample SLM-PB-S with the building orientation parallel to the substrate and the shorter side L1 contacts it, sample SLM-PB-L with the building orientation parallel to the substrate and the longer side L2 contacts it and sample SLM-VB with the building orientation vertical to the substrate. Subsequently, the microstructure, grain information, densification, residual stress, micro-hardness, tensile properties and surface topography of different samples were analyzed and compared. In the results, SLM-PB-S exhibited denser microstructure and better mechanical properties than SLM-PB-L, including smaller grain size, stronger texture, higher density, micro-hardness, tensile strength, plasticity and better surface quality. It originates from a higher cooling rate and shorter scanning time between layers during SLM-PB-S fabrication, leading to finer grains, lower porosity and better interlayer metallurgical bonding, thus resulting in better material properties. This study can provide a reference to select the proper building orientation in SLM.

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Continuous and pulsed selective laser melting of Ti6Al4V lattice structures: Effect of post-processing on microstructural anisotropy and fatigue behaviour

Cited by 41 publications

References 60 publications

Additive Manufacturing of AlSi10Mg and Ti6Al4V Lightweight Alloys via Laser Powder Bed Fusion: A Review of Heat Treatments Effects

Additive Manufacturing of AlSi10Mg and Ti6Al4V Lightweight Alloys via Laser Powder Bed Fusion: A Review of Heat Treatments Effects

Influence of relative density on quasi-static and fatigue failure of lattice structures in Ti6Al4V produced by laser powder bed fusion

Multi-Perspective Analysis of Building Orientation Effects on Microstructure, Mechanical and Surface Properties of SLM Ti6Al4V with Specific Geometry

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