2020 Fiscal Year Research-status Report
In-situ formation of ceramic protective coating on Mo-based composites by laser powder bed fusion
| Project/Area Number |
20K15036
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| Research Institution | Tohoku University |
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Principal Investigator |
周 偉偉 東北大学, 工学研究科, 助教 (10800352)
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| Project Period (FY) |
2020-04-01 – 2022-03-31
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| Keywords | Laser powder bed fusion / Mo-based composites / Coatings / Hetero-agglomeration / Oxidation resistance |
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| Outline of Annual Research Achievements |
I have uniformly decorated ceramic nanoparticles on the surface of Mo-based alloy powders using acid-treated carbon nanotubes (CNTs) or nanobubbles as bridging agents during a hetero-agglomeration process.The effect of ceramic contents on the properties of composite powders was investigated. The composite powders possessed homogenous dispersion, good flowability, improved laser absorptivity, suitable particle size and distribution. Moreover, laser powder bed fusion (L-PBF) was performed for the fabrication of Mo-based composite bulks. The microstructure evolution of ceramic reinforcements or metal matrix during L-PBF was studied. Through reducing the scanning speed, a thin ceramic layer was introduced on the top surface of L-PBF composite builds.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
The objective of this proposal is to simultaneously enhance the mechanical performance and oxidation resistance of Mo-based alloys by L-PBF. This year, the approaches of fabricating uniform ceramic/Mo-based composite powders were successfully developed as scheduled. Moreover, an in-situ protective layer was possibly formed on Mo-based composites by controlling the L-PBF processing of nanoceramic-decorated alloy powders, which is smoother than initially planned.
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| Strategy for Future Research Activity |
Based on the research plan, the formation mechanism of ceramic coatings during L-PBF will be clarified by single-track experiments and theoretical simulation. The influence of building layers or ceramic concentrations on the ceramic layer formation such as thickness or chemical composition will be studied. Moreover, the room-/high-temperature mechanical property and oxidation resistance are systematically evaluated for confirming the application potential of Mo-based composites.
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| Causes of Carryover |
For consumables expenses, such as argon gas, polishing materials, microstructure observation cost, and L-PBF consumables. The argon gas is used as protective gas during L-PBF process. The polishing materials like sandpapers, or polishing paste are needed for sample preparation. The TEM, SEM and EBSD are required for microstructural observations. The L-PBF consumables (e.g., brushes, bottles) and Ti substrates are needed for fabricating Mo-based composites.
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