The Effect of Interpass Peening on Mechanical Properties in Additive Manufacturing of Ti-6Al-4V

Byun, Jae-Gyu; Yi, Hui-Jun; Cho, Sang-Myung

doi:10.5781/jwj.2017.35.2.2

Cited by 6 publications

(7 citation statements)

References 9 publications

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“…The preferential direction of elongation for the vertical direction with a decrease in strength is eliminated and isotropic properties are achieved through the grain refinement induced by inter-pass MHP. Similar properties have been reported in Byun et al [13].…”

Section: Tensile Propertiessupporting

confidence: 91%

“…Also, the rolling speed reported ranges from 3 to 7 mm/s [7,11], which may increase significantly the production time of the WAAM components. Machine Hammer Peening (MHP) has been previously studied as an alternative to this technology [11][12][13]. It is shown that MHP has the capability of refining the previously columnar β grains and that it can be applied robotically, guaranteeing the flexibility and repeatability required to employ this technology to WAAM components.…”

Section: Introductionmentioning

confidence: 99%

“…The MHP speed is also 18 mm/s [11], which is much greater than rolling, although the transformed area is not as wide as with rolling. In another study [13], it is also reported that an increase in tensile properties and grain refinement is achieved, but the methodology used for MHP and deposition is unclear.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties Enhancement of Additive Manufactured Ti-6Al-4V by Machine Hammer Peening

Neto

Williams

Ding

et al. 2019

Lecture Notes in Mechanical Engineering

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Wire + Arc Additive Manufacturing (WAAM) is a technology potentially offering reduction of material wastage, costs and shorter lead-times. It is being considered as a technology that could replace conventional manufacturing processes of Ti-6Al-4V, such as machining from wrought or forged materials. However, WAAM Ti-6Al-4V is characterized by coarse β-grains, which can extend through several deposited layers resulting in strong texture and anisotropy. As a solution, inter-pass cold rolling has been proven to promote grain refinement, texture modification and improvement of material strength by plastically deforming the material between each deposited layer. Nevertheless, with the increased interest in the WAAM technology, the complexity and size of the deposited parts has increased, and its application can be hindered by the low speed and complex/costly equipment required to perform rolling at this scale. Therefore, Machine Hammer Peening (MHP) has been studied as an alternative cold work process. MHP can be used robotically, offering greater flexibility and speed, and it can be applied easily to any large-scale geometry. Similarly to rolling, MHP is applied between each deposited layer with the new ECOROLL peening machine and, consequently, it is possible to eliminate texturing and reduce the β-grains size from centimeters long to approximately 1 to 2 mm. This effect is studied for thin and thick walls and no considerable change in grain size is observed, proving the applicability of MHP to large components. The yield strength and ultimate tensile strength increases to 907 MPa and 993 MPa, respectively, while still having excellent ductility. This grain refinement may also improve fatigue life and induce a decrease in crack propagation rate. In this study, it has been shown that MHP is a suitable process for WAAM Ti-6Al-4V applications, can be applied robotically and the grain refinement induced by very small plastic deformations can increase mechanical properties.

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Section: Tensile Propertiessupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanical Properties Enhancement of Additive Manufactured Ti-6Al-4V by Machine Hammer Peening

Neto

Williams

Ding

et al. 2019

Lecture Notes in Mechanical Engineering

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“…The tool can be easily used with a robotic arm, which offers the possibility of applying cold work to potentially any geometry [23]. Inter-pass MHP was first studied by Byun et al [24]. An average β grain size of 460 µm was obtained, and the α laths size decreased by ~40% from the as deposited condition, which increased the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Machine Hammer Peening Conditions on β Grain Refinement of Additively Manufactured Ti-6Al-4V

Neto,

Williams,

Davis

et al. 2023

Metals

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Ti-6Al-4V components built with wire plus arc additive manufacturing (WAAM) generally have long columnar β grains that cause anisotropic behavior when the material undergoes static and cyclic failure. Recently, machine hammer peening (MHP) has been proved to induce prior-β grain refinement in WAAM resulting in isotropic properties and increased strength. In this study, MHP was investigated for WAAM walls to establish the dependency of the β grain refinement on peening parameters, such as energy, tool radius, and distance between impact steps. All combinations of parameters investigated resulted in grain-refined microstructures. The plastic strain theory failed to explain these results, as the microstructure refinement achieved did not match the strain distribution obtained. Thus, a new theory of accumulated energy was proposed in which the dynamic deformation of the MHP process should also be taken into consideration. The mechanical properties for the MHP conditions showed higher strength and decreased anisotropy as the energy per length increased. This was attributed to the reduction in texture in the WAAM walls. Thus, when applying MHP, the energy per unit length is controlling the grain size obtained and improved mechanical properties can be achieved.

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“…To overcome the issues, additive manufacture (AM) has been developed as a promising technology to fabricate a three-dimensional net-shaped product in a manner of layer-by-layer. The feature of net-shaped can minimize the material waste, which increases the buy-to-fly ratio and subsequently enhances the cost-effectiveness 6,7) . AM can be divided into powder bed fusion (PBF) and directed energy deposition (DED) based on the principle process.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Decomposed Microstructure on Mechanical Properties of Additively Manufactured Ti-6Al-4V Alloy

Nursyifaulkhair

Park

Baek

2021

Journal of Welding and Joining

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This study investigated the effect of microstructural decomposition on the mechanical properties of additively manufactured Ti-6Al-4V by directed energy deposition. The formation of ' martensite and massive phase ( m ) was observed in the deposited layers. The ' and m in the lastly deposited layer appeared as a needle-shaped and a sub-lamellar structure, respectively. However, the morphology of ' and m was decomposed in the lower layers due to the intrinsic heat treatment. Moreover, The heat conduction rate calculation showed that the lower powder feed rate generates more heat conduction. Therefore, the microstructure was further decomposed for the specimen with a lower powder feed rate. These phenomena consequently affected the mechanical properties and fracture behavior of the Ti-6Al-4V alloy.

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The Effect of Interpass Peening on Mechanical Properties in Additive Manufacturing of Ti-6Al-4V

Cited by 6 publications

References 9 publications

Mechanical Properties Enhancement of Additive Manufactured Ti-6Al-4V by Machine Hammer Peening

Mechanical Properties Enhancement of Additive Manufactured Ti-6Al-4V by Machine Hammer Peening

Effect of Machine Hammer Peening Conditions on β Grain Refinement of Additively Manufactured Ti-6Al-4V

The Effect of Decomposed Microstructure on Mechanical Properties of Additively Manufactured Ti-6Al-4V Alloy

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