β grain refinement during solidification of Ti-6Al-4V in Wire-Arc Additive Manufacturing (WAAM)

Kennedy, J. R.; Davis, Alec; Caballero, Armando; Pickering, Ed; Prangnell, P.B.

doi:10.1088/1757-899x/1274/1/012005

Cited by 5 publications

(3 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Regarding the geometrically more complex structures being present in Ti-0.44O-0.5Fe-0.08C-0.4Si-0.1Au-(0.3/0.5/1.0)Y, similar structures have already been reported in the literature (Kennedy et al, 2022;Kennedy et al, 2023) and been described as having a similar shape to structures formed during irregular eutectic solidification (Kennedy et al, 2022). The present results shown in Figure 10 seem to support this assumption of eutectic solidification.…”

Section: Solidification and Microstructuresupporting

confidence: 90%

See 1 more Smart Citation

Laser powder bed fusion (LPBF) of commercially pure titanium and alloy development for the LPBF process

Haase,

Siemers,

Rösler

2023

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

Laser powder bed fusion (LPBF) of titanium or titanium alloys allows fabrication of geometrically more complex and, possibly, individualized implants or osteosynthesis products and could thus improve the outcome of medical treatments considerably. However, insufficient LPBF process parameters can result in substantial porosity, decreasing mechanical properties and requiring post-treatment. Furthermore, texturized parts with anisotropic properties are usually obtained after LPBF processing, limiting their usage in medical applications. The present study addresses both: first, a design of experiments is used in order to establish a set of optimized process parameters and a process window for LPBF printing of small commercially pure (CP) titanium parts with minimized volume porosity. Afterward, the first results on the development of a biocompatible titanium alloy designed for LPBF processing of medical implants with improved solidification and more isotropic properties are presented on the basis of conventionally melted alloys. This development was performed on the basis of Ti-0.44O-0.5Fe-0.08C-0.4Si-0.1Au, a near-α alloy presented by the authors for medical applications and conventional manufacturing, with yttrium and boron additions as additional growth restriction solutes. In terms of LPBF processing of CP titanium grade 1 powder, a high relative density of approximately 99.9% was obtained in the as-printed state of the volume of a small cubical sample by using optimized laser power, scanning speed, and hatch distance in combination with a rotating scanning pattern. Moreover, tensile specimens processed with these volume settings and tested in the as-printed milled state exhibited a high average yield and ultimate tensile strength of approximately 663 and 747 N/mm2, respectively, combined with a high average ductility of approximately 24%. X-ray diffraction results suggest anisotropic mechanical properties, which are, however, less pronounced in terms of the tested specimens. Regarding alloy development, the results show that yttrium additions lead to a considerable microstructure refinement but have to be limited due to the occurrence of a large amount of precipitations and a supposed higher propensity for the formation of long columnar prior β-grains. However, phase/texture and microstructure analyses indicate that Ti-0.44O-0.5Fe-0.08C-0.4Si-0.1Au-0.1B-0.1Y is a promising candidate to achieve lower anisotropy during LPBF processing, but further investigations on LPBF printing and Y2O3 formation are necessary.

show abstract

Section: Solidification and Microstructuresupporting

confidence: 90%

“…Therefore, the latter might not always be isolated particles. In general, such kind of geometrically more complex structures as identified in Ti-0.44O-0.5Fe-0.08C-0.4Si-0.1Au-(0.3/0.5/1.0)Y have already been reported in the literature ( Kennedy et al, 2022 ; Kennedy et al, 2023 ). This will be discussed in more detail later.…”

Section: Resultsmentioning

confidence: 76%

Laser powder bed fusion (LPBF) of commercially pure titanium and alloy development for the LPBF process

Haase,

Siemers,

Rösler

2023

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

show abstract

“…Alternative solutions may be microalloying the melt pool to extend the constitutional undercooled zone and, thus, increase the probability of homogeneous grain nucleation [28] or intensifying the heterogeneous grain nucleation by adding refractory inoculation particles [29]. The first two approaches involve increased design complexity, while admixing alloying and inoculation additives is not always desirable from the viewpoint of maintaining the chemical composition.…”

Section: Introductionmentioning

confidence: 99%

Effect of “ColdArc” WAAM Regime and Arc Torch Weaving on Microstructure and Properties of As-Built and Subtransus Quenched Ti-6Al-4V

Zykova,

Savchenko,

Nikolaeva

et al. 2024

Materials

View full text Add to dashboard Cite

Defect-free thin-walled samples were built using wire arc additive manufacturing (WAAM) combined with the “coldArc” deposition technique by feeding a Ti-6Al-4V welding wire and using two deposition strategies, namely with and without the welding torch weaving. The microstructures formed in these samples were examined in relation to mechanical characteristics. The arc torch weaving at 1 Hz allowed us to interfere with the epitaxial growth of the β-Ti columnar grains and, thus, obtain them a lower aspect ratio. Upon cooling, the α/α′+β structure was formed inside the former β-Ti grains, and this structure proved to be more uniform as compared to that of the samples built without the weaving. The subtransus quenching of the samples in water did not have any effect on the structure and properties of samples built with the arc torch weaving, whereas a more uniform grain structure was formed in the sample built without weaving. Quenching resulted also in a reduction in the relative elongation by 30% in both cases.

show abstract

Preventing columnar grains growth during hybrid wire arc additive manufacturing of austenitic stainless steel 316L

Albannai,

León‐Henao,

Ramirez

2024

Engineering Reports

View full text Add to dashboard Cite

Wire arc additive manufacturing (WAAM) is an efficient technique for producing medium to large‐size components, due to its accessibility and sustainability in fabricating large‐scale parts with high deposition rates, employing low‐cost and simple equipment, and achieving high material efficiency. Consequently, WAAM has garnered attention across various industrial sectors and experienced significant growth, particularly over the last decade, as it addresses and mitigates challenges within production markets. One of the primary limitations of WAAM is its thermal history during the process, which directly influences grain formation and microstructure heterogeneity in the resulting part. Understanding the thermal cycle of the WAAM process is thus crucial for process improvement. Typically, fabricating a part using WAAM results in a microstructure with three distinct zones along the build direction: an upper zone (thin surface layer) with fine grains, a middle zone dominated by undesirably long and large columnar grains covering more than 90% of the produced part, and a lower zone with smaller to intermediate columnar grains closer to the substrate material. These zones arise from variations in cooling rates, with the middle zone exhibiting the lowest cooling rate due to 2D conduction heat transfer. Consequently, producing a component with a microstructure comprising three different zones, with a high fraction of large and long columnar grains, significantly impacts the final mechanical properties. Therefore, controlling the size and formation of these grain zones plays a key role in improving WAAM. The aim of this work is to investigate the formation of undesired columnar grains in austenitic stainless steel 316L during WAAM and propose a simple hybrid technique by combining WAAM with a hot forging process (with or without interlayer cooling time). This approach targets the disruption of the solidification pattern of columnar grain growth during deposition progression and aims to enhance the microstructure of WAAM components.

show abstract

β grain refinement during solidification of Ti-6Al-4V in Wire-Arc Additive Manufacturing (WAAM)

Cited by 5 publications

References 33 publications

Laser powder bed fusion (LPBF) of commercially pure titanium and alloy development for the LPBF process

Laser powder bed fusion (LPBF) of commercially pure titanium and alloy development for the LPBF process

Effect of “ColdArc” WAAM Regime and Arc Torch Weaving on Microstructure and Properties of As-Built and Subtransus Quenched Ti-6Al-4V

Preventing columnar grains growth during hybrid wire arc additive manufacturing of austenitic stainless steel 316L

Contact Info

Product

Resources

About