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Vol.58, No.12, 843 ~ 852, 2020
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| Title |
| Microstructure and Mechanical Properties of Ni-Cr-Y2O3 Alloy Sintered Powder Composed of Oxide-Embedded Metallic Particles |
| Changjae Kim , Jungho Gwak , Jaewon Lim , Minsuk Oh , Jeshin Park |
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| Abstract |
| In this study, oxide (Y2O3)-embedded Ni particles were fabricated via a new process. The process involves the mechanical hydrogenation of Ni-Y alloy into Ni-YH2 and the selective oxidation of Ni-YH2 to Ni-Y2O3. The alloy powders were prepared for sintering by the mechanical alloying of a mixed powder. The powder was prepared with a desired composition (Ni-20wt.%Cr-1.2wt.%Y2O3) by adding Ni and Cr powders to the Ni-Y2O3 composite prepared by the new process. For comparison, a mixed powder with the same composite was prepared using a conventional mechanical alloying (MA) approach. Samples of the two powders were sintered by SPS at 850, 900, 950, and 1,000℃. The relative densities of all samples were higher than 99.7% at all sintering temperatures. The oxide particles and matrix grain sizes of the Ni-20Cr-1.2Y2O3 alloy prepared by this new process were finer than those in alloys fabricated by conventional MA processes. Therefore, the improvement in the mechanical properties of the Ni-20Cr-1.2Y2O3 alloy prepared by the new process was attributed to the refinement of the oxide particles.
(Received September 14, 2020; Accepted October 7, 2020) |
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| Key Words |
| oxide-embedded Ni particles, oxide dispersion-strengthened alloys, selective oxidation, spark plasma sintering, mechanical properties, mechanochemical processing |
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