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Additive manufacturing of high-strength crack-free Ni-based Hastelloy X superalloy
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Sam L. Evans,
Shoufeng Yang
Additive Manufacturing, Volume: 30, Start page: 100919
Swansea University Author:
Richard Johnston
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DOI (Published version): 10.1016/j.addma.2019.100919
Abstract
Laser powder bed fusion (LPBF) is a proven additive manufacturing (AM) technology for producing metallic components with complex shapes using layer-by-layer manufacture principle. However, the fabrication of crack-free high-performance Ni-based superalloys such as Hastelloy X (HX) using LPBF technol...
| Published in: | Additive Manufacturing |
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| ISSN: | 2214-8604 |
| Published: |
Elsevier BV
2019
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa52481 |
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| Abstract: |
Laser powder bed fusion (LPBF) is a proven additive manufacturing (AM) technology for producing metallic components with complex shapes using layer-by-layer manufacture principle. However, the fabrication of crack-free high-performance Ni-based superalloys such as Hastelloy X (HX) using LPBF technology remains a challenge because of these materials’ susceptibility to hot cracking. This paper addresses the above problem by proposing a novel method of introducing 1 wt.% titanium carbide (TiC) nanoparticles. The findings reveal that the addition of TiC nanoparticles results in the elimination of microcracks in the LPBF-fabricated enhanced HX samples; i.e. the 0.65% microcracks that were formed in the as-fabricated original HX were eliminated in the as-fabricated enhanced HX, despite the 0.14% residual pores formed. It also contributes to a 21.8% increase in low-angle grain boundaries (LAGBs) and a 98 MPa increase in yield strength. The study revealed that segregated carbides were unable to trigger hot cracking without sufficient thermal residual stresses; the significantly increased subgrains and low-angle grain boundaries played a key role in the hot cracking elimination. These findings offer a new perspective on the elimination of hot cracking of nickel-based superalloys and other industrially relevant crack-susceptible alloys. The findings also have significant implications for the design of new alloys, particularly for high-temperature industrial applications. |
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| Keywords: |
Powder bed fusion, nickel-based superalloy, Hastelloy X, cracking, nanoparticle |
| College: |
Faculty of Science and Engineering |
| Start Page: |
100919 |