Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/10916
Title: The effect of milling time on the microstructural characteristics and strengthening mechanisms of NiMo-SiC alloys prepared via powder metallurgy
Authors: Yang, C
Muránsky, O
Zhu, HL
Thorogood, GJ
Avdeev, M
Huang, HF
Zhou, XT
Keywords: Powder metallurgy
Transmission electron microscopy
Backscattering
Molten salt reactors
Alloys
Neutron diffraction
Issue Date: 6-Apr-2017
Publisher: Multidisciplinary Digital Publishing Institute
Citation: Yang, C., Muránsky, O., Zhu, H., Thorogood, G. J., Avdeev, M., Huang, H., & Zhou, X. (2017). The effect of milling time on the microstructural characteristics and strengthening mechanisms of NiMo-SiC alloys prepared via powder metallurgy. Materials, 10(4), 389. doi:10.3390/ma10040389
Abstract: A new generation of alloys, which rely on a combination of various strengthening mechanisms, has been developed for application in molten salt nuclear reactors. In the current study, a battery of dispersion and precipitation-strengthened (DPS) NiMo-based alloys containing varying amounts of SiC (0.5–2.5 wt %) were prepared from Ni-Mo-SiC powder mixture via a mechanical alloying (MA) route followed by spark plasma sintering (SPS) and rapid cooling. Neutron Powder Diffraction (NPD), Electron Back Scattering Diffraction (EBSD), and Transmission Electron Microscopy (TEM) were employed in the characterization of the microstructural properties of these in-house prepared NiMo-SiC DPS alloys. The study showed that uniformly-dispersed SiC particles provide dispersion strengthening, the precipitation of nano-scale Ni3Si particles provides precipitation strengthening, and the solid-solution of Mo in the Ni matrix provides solid-solution strengthening. It was further shown that the milling time has significant effects on the microstructural characteristics of these alloys. Increased milling time seems to limit the grain growth of the NiMo matrix by producing well-dispersed Mo2C particles during sintering. The amount of grain boundaries greatly increases the Hall–Petch strengthening, resulting in significantly higher strength in the case of 48-h-milled NiMo-SiC DPS alloys compared with the 8-h-milled alloys. However, it was also shown that the total elongation is considerably reduced in the 48-h-milled NiMo-SiC DPS alloy due to high porosity. The porosity is a result of cold welding of the powder mixture during the extended milling process. © This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
URI: https://doi.org/10.3390/ma10040389
https://apo.ansto.gov.au/dspace/handle/10238/10916
ISSN: 1996-1944
Appears in Collections:Journal Articles

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