Combining alloy and process modification for micro-crack mitigation in an additively manufactured Ni-base superalloy

Griffiths, Seth; Ghasemi-Tabasi, Hossein; Ivas, Toni; Maeder, Xavier; Luca, Anthony De; Zweiacker, Kai; Wróbel, Rafał; Jhabvala, Jamasp; Logé, Roland E.; Leinenbach, Christian

doi:10.1016/j.addma.2020.101443

Cited by 55 publications

(60 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Elements like Cr and Fe then have a more uniform distribution behavior across dendrites and interdendrites, resulting in the value of these two elements very close to 1. In AM-processed alloys, similar solidification segregations are widely reported in a selective electron beam melted (SEBM) CMSX-4 superalloy [22], an LPBF CM247LC superalloy [161], a laser beam welded (LBW) IN718 superalloy [163], an LPBF 316L steel [164], an LPBF IN718 [162]. Additionally, the next step is to sort out the elemental concentration profile at the DC and ID regions.…”

Section: Segregation Behavior In Lpbfmentioning

confidence: 77%

See 1 more Smart Citation

Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing

2021

Linköping Studies in Science and Technology. Licentiate Thesis

View full text Add to dashboard Cite

Nickel-based superalloys, an alloy system bases on nickel as the matrix element with the addition of up to 10 more alloying elements including chromium, aluminum, cobalt, tungsten, molybdenum, titanium, and so on. Through the development and improvement of nickel-based superalloys in the past century, they are well proved to show excellent performance at the elevated service temperature. Owing to the combination of extraordinary high-temperature mechanical properties, such as monotonic and cyclic deformation resistance, fatigue crack propagation resistance; and high-temperature chemical properties, such as corrosion and oxidation resistance, phase stability, nickel-based superalloys are widely used in the critical hot-section components in aerospace and energy generation industries. The success of nickel-based superalloy systems attributes to both the well-tailored microstructures with the assistance of carefully doped alloying elements, and the intently developed manufacturing processes. The microstructure of the modern nickel-based superalloys consists of a two-phase configuration: the intermetallic precipitates (Ni,Co)3(Al,Ti,Ta) known as γ′ phase dispersed into the austenite γ matrix, which is firstly introduced in the 1940s. The recently developed additive manufacturing (AM) techniques, acting as the disruptive manufacturing process, offers a new avenue for producing the nickel-based superalloy components with complicated geometries. However, γ′ strengthened nickel-based superalloys always suffer from the micro-cracking during the AM process, which is barely eliminated by the process optimization. On this basis, the new compositions of γ′ strengthened nickel-based superalloy adapted to the AM process are of great interest and significance. This study sought to design novel γ′ strengthened nickel-based superalloys readily for AM process with limited cracking susceptibility, based on the understanding of the cracking mechanisms. A two-parameter model is developed to predict the additive manufacturability for any given composition of a nickel-based superalloy. One materials index is derived from the comparison of the deformation-resistant capacity between dendritic and interdendritic regions, while another index is derived from the difference of heat resistant capacity of these two spaces. By plotting the additive manufacturability diagram, the superalloys family can be categorized into the easy-to-weld, fairly-weldable, and non-weldable regime with the good agreement of the existed knowledge. To design a novel superalloy, a Cr-Co-MoW -Al-Ti-Ta-Nb-Fe-Ni alloy family is proposed containing 921,600 composition recipes in total. Through the examination of additive manufacturability, undesired phase formation propensity, and the precipitation fraction, one composition of superalloy, MAD542, out of the 921,600 candidates is selected. Validation of additive manufacturability of MAD542 is carried out by laser powder bed fusion (LPBF). By optimizing the LPBF process parameters, the crack-free MAD542 part is achieved. I...

show abstract

Section: Segregation Behavior In Lpbfmentioning

confidence: 77%

“…This has been supported by extensive researches on the as-LPBF-processed alloys by using high-resolution composition measurement techniques, e.g. Energy Dispersive X-ray Spectroscopy (EDS) in the TEM [161,162].…”

Section: Segregation Behavior In Lpbfmentioning

confidence: 98%

Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing

2021

Linköping Studies in Science and Technology. Licentiate Thesis

View full text Add to dashboard Cite

show abstract

“…This emphasizes the fact that modification of process parameters is a practical approach to control defect formation (pores, cracks, etc.) in the final printed samples [50,51]. Irregular pores located in the vicinity of the part surface are due to partially melted/ sintered/entrapped metallic powder particles, which stick to and agglomerate on the outer edge of the melt pool.…”

Section: Resultsmentioning

confidence: 99%

Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

et al. 2021

Self Cite

View full text Add to dashboard Cite

A crucial criterion for the quality of the additively manufactured parts is the porosity content for achieving an acceptable final relative density. In addition, for jewelry applications, visible pores are unacceptable at or in the vicinity of the surface. In this study, non-destructive 3D neutron microtomography is applied to map the spatial distribution of pores in additively manufactured red-gold samples. The 3D imaging assessment underlines the high relative density of the printed red-gold sample and indicates residual pore sizes are predominantly below the limit of concern for jewelry applications. The 3D maps of pores within printed samples highlight the effect of the scanning strategy on the final quality and location of pores in the printed samples. These results confirm that neutron microtomography is a novel and precise tool to characterize residual porosity in additively manufactured gold alloys and other higher-Z materials where such investigation using other non-destructive methods (such as X-rays) is challenging due to the limited penetration depth.

show abstract

“…The LPBF process involves extremely high solidification rates that avoid a complete chemical element diffusion of the Ti-rich particles necessary to reach a full homogenization. More in detail, Ti tends to segregate to the interdendritic areas during the solidification, reducing the quantity of Ti assimilated within the austenitic matrix [41][42][43]. The limited dissolution of Ti was also clearly pointed out by the lattice parameter of the austenitic…”

Section: Discussionmentioning

confidence: 99%

In Situ Alloying of a Modified Inconel 625 via Laser Powder Bed Fusion: Microstructure and Mechanical Properties

Marchese

Beretta

Aversa

et al. 2021

Metals

View full text Add to dashboard Cite

This study investigates the in situ alloying of a Ni-based superalloy processed by means of laser powder bed fusion (LPBF). For this purpose, Inconel 625 powder is mixed with 1 wt.% of Ti6Al4V powder. The modified alloy is characterized by densification levels similar to the base alloy, with relative density superior to 99.8%. The material exhibits Ti-rich segregations along the melt pool contours. Moreover, Ti tends to be entrapped in the interdendritic areas during solidification in the as-built state. After heat treatments, the modified Inconel 625 version presents greater hardness and tensile strengths than the base alloy in the same heat-treated conditions. For the solution annealed state, this is mainly attributed to the elimination of the segregations into the interdendritic structures, thus triggering solute strengthening. Finally, for the aged state, the further increment of mechanical properties can be attributed to a more intense formation of phases than the base alloy, due to elevated precipitation strengthening ability under heat treatments. It is interesting to note how slight chemical composition modification can directly develop new alloys by the LPBF process.

show abstract

Combining alloy and process modification for micro-crack mitigation in an additively manufactured Ni-base superalloy

Cited by 55 publications

References 26 publications

Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing

Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing

Mapping Spatial Distribution of Pores in an Additively Manufactured Gold Alloy Using Neutron Microtomography

In Situ Alloying of a Modified Inconel 625 via Laser Powder Bed Fusion: Microstructure and Mechanical Properties

Contact Info

Product

Resources

About