Improved fatigue endurance ratio of additive manufactured Ti-6Al-4V lattice by hot isostatic pressing

Wu, Ming-Wei; Chen, Jhewn‐Kuang; Lin, Bo-Huan; Chiang, Po-Hsing

doi:10.1016/j.matdes.2017.08.048

Cited by 85 publications

(20 citation statements)

References 36 publications

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“…That is particularly beneficial in dynamically loaded applications [36]. Furthermore, HIP has been shown to significantly improve the fatigue performance of lattice structures [69]. The ASTM F2924 [68] class 1 treatment, also referred to as the stress relieved condition, slightly increases the mechanical properties of the Ti-6Al-4V lattices; however, it also makes them more brittle [36,67].…”

Section: Discussionmentioning

confidence: 99%

Non-Auxetic Mechanical Metamaterials

2019

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The concept of “mechanical metamaterials” has become increasingly popular, since their macro-scale characteristics can be designed to exhibit unusual combinations of mechanical properties on the micro-scale. The advances in additive manufacturing (AM, three-dimensional printing) techniques have boosted the fabrication of these mechanical metamaterials by facilitating a precise control over their micro-architecture. Although mechanical metamaterials with negative Poisson’s ratios (i.e., auxetic metamaterials) have received much attention before and have been reviewed multiple times, no comparable review exists for architected materials with positive Poisson’s ratios. Therefore, this review will focus on the topology-property relationships of non-auxetic mechanical metamaterials in general and five topological designs in particular. These include the designs based on the diamond, cube, truncated cube, rhombic dodecahedron, and the truncated cuboctahedron unit cells. We reviewed the mechanical properties and fatigue behavior of these architected materials, while considering the effects of other factors such as those of the AM process. In addition, we systematically analyzed the experimental, computational, and analytical data and solutions available in the literature for the titanium alloy Ti-6Al-4V. Compression dominated lattices, such as the (truncated) cube, showed the highest mechanical properties. All of the proposed unit cells showed a normalized fatigue strength below that of solid titanium (i.e., 40% of the yield stress), in the range of 12–36% of their yield stress. The unit cells discussed in this review could potentially be applied in bone-mimicking porous structures.

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Section: Discussionmentioning

confidence: 99%

Non-Auxetic Mechanical Metamaterials

2019

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“…To reduce the porosity in AM parts, hot isostatic pressing is commonly used, where porous parts are subjected to high pressure and temperature [127][128][129]. Wu et al [130] observed a significant improvement in fatigue properties upon hot isostatic pressing of Ti6Al4V lattice structures, quantified by an increased endurance ratio of approximately 80%. The improved fatigue properties were attributed to a phase change from brittle α′-martensite to tough α + β mixed phases causing an increase in toughness-the key material property for resisting crack propagation.…”

Section: Post-processingmentioning

confidence: 99%

Review of defects in lattice structures manufactured by powder bed fusion

Echeta

Feng

Dutton

et al. 2019

Int J Adv Manuf Technol

141

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Additively manufactured lattice structures are popular due to their desirable properties, such as high specific stiffness and high surface area, and are being explored for several applications including aerospace components, heat exchangers and biomedical implants. The complexity of lattices challenges the fabrication limits of additive manufacturing processes and thus, lattices are particularly prone to manufacturing defects. This paper presents a review of defects in lattice structures produced by powder bed fusion processes. The review focuses on the effects of lattice design on dimensional inaccuracies, surface texture and porosity. The design constraints on lattice structures are also reviewed, as these can help to discourage defect formation. Appropriate process parameters, post-processing techniques and measurement methods are also discussed. The information presented in this paper contributes towards a deeper understanding of defects in lattice structures, aiming to improve the quality and performance of future designs.

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“…The majority of studies concern the phenomena of lattice fatigue failure or ways to improve their fatigue strength, while a few concern the fatigue properties of lattice structures and especially the methods to predict fatigue life. Wu et al [13] investigated the influence of hot isostatic pressing (HIP) on the fatigue properties of additive manufactured Ti-6Al-4V lattice with a self-designed unit cell, which shows that the HIP treatment can improve the fatigue strength and endurance limit. Other studies show that fatigue properties of the lattice materials are highly dependent on the type of unit cell as well as on porosity [14][15].…”

Section: Introductionmentioning

confidence: 99%

Fatigue of thin periodic triangular lattice plates

Shterenlikht

Pavier

et al. 2019

MATEC Web Conf.

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A method for predicting the fatigue life of triangular lattices is proposed in this paper by considering fatigue properties of single lattice struts. Fatigue tests of different sizes of lattice plates of aluminium alloy, and tests of single struts with different maximum fluctuating loads, have been conducted to validate this method. It is found that the struts in a triangular lattice break near to strut intersections, where stress and strain concentrations occur. Similar crack propagation paths were observed in different lattice plate specimens: the cracks grew at a 30° angle to the initial edge crack in the upper half of lattice plate. The mixed-mode fatigue crack propagation rate was also studied and expressed using an effective stress intensity factor. A size effect on the crack growth rate of triangular lattice plates was also observed: a fatigue crack will propagate slightly quicker in larger triangular plates than in smaller ones.

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Improved fatigue endurance ratio of additive manufactured Ti-6Al-4V lattice by hot isostatic pressing

Cited by 85 publications

References 36 publications

Non-Auxetic Mechanical Metamaterials

Non-Auxetic Mechanical Metamaterials

Review of defects in lattice structures manufactured by powder bed fusion

Fatigue of thin periodic triangular lattice plates

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