Pore evolution mechanisms during directed energy deposition additive manufacturing

DOI: 10.1038/s41467-024-45913-9

Authors: Kai Zhang (University College London; Research Complex at Harwell) , Yunhui Chen (University College London; Research Complex at Harwell; ESRF-The European Synchrotron; RMIT University) , Sebastian Marussi (University College London; Research Complex at Harwell) , Xianqiang Fan (University College London; Research Complex at Harwell) , Maureen Fitzpatrick (University College London; ESRF-The European Synchrotron) , Shishira Bhagavath (University College London; Research Complex at Harwell) , Marta Majkut (ESRF-The European Synchrotron) , Bratislav Lukic (ESRF-The European Synchrotron) , Kudakwashe Jakata (ESRF-The European Synchrotron; Diamond Light Source) , Alexander Rack (ESRF-The European Synchrotron) , Martyn A. Jones (Rolls-Royce plc) , Junji Shinjo (Shimane University) , Chinnapat Panwisawas (Queen Mary University of London) , Chu Lun Alex Leung (University College London; Research Complex at Harwell) , Peter D. Lee (University College London; Research Complex at Harwell)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Nature Communications , VOL 15

State: Published (Approved)
Published: February 2024

Abstract: Porosity in directed energy deposition (DED) deteriorates mechanical performances of components, limiting safety-critical applications. However, how pores arise and evolve in DED remains unclear. Here, we reveal pore evolution mechanisms during DED using in situ X-ray imaging and multi-physics modelling. We quantify five mechanisms contributing to pore formation, migration, pushing, growth, removal and entrapment: (i) bubbles from gas atomised powder enter the melt pool, and then migrate circularly or laterally; (ii) small bubbles can escape from the pool surface, or coalesce into larger bubbles, or be entrapped by solidification fronts; (iii) larger coalesced bubbles can remain in the pool for long periods, pushed by the solid/liquid interface; (iv) Marangoni surface shear flow overcomes buoyancy, keeping larger bubbles from popping out; and (v) once large bubbles reach critical sizes they escape from the pool surface or are trapped in DED tracks. These mechanisms can guide the development of pore minimisation strategies.

Journal Keywords: Computational methods; Fluid dynamics; Imaging techniques Mechanical engineering; Metals and alloys

Diamond Keywords: Additive Manufacturing; Alloys

Subject Areas: Materials, Engineering

Facility: ID19 at ESRF

Added On: 26/02/2024 09:52

Documents:
s41467-024-45913-9.pdf

Discipline Tags:

Materials Engineering & Processes Aerospace Materials Science Engineering & Technology Metallurgy

Technical Tags: