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Wang B.,Shanghai University | Zhou B.,Shanghai University | Wang Z.,Shanghai University | Huang J.,Shanghai University | And 2 more authors.
Jinshu Xuebao/Acta Metallurgica Sinica | Year: 2015

Zirconium alloys with low alloying content are mainly used in the nuclear industry as structural materials because of their superior properties in terms of thermal neutron transparency, mechanical strength and corrosion resistance. They are used for fuel cladding tubes and channels. The reaction between zirconium and water at high temperature forms oxide film on the surfaces. In order to further improve the corrosion resistance of Zrbased cladding tubes, research has continued on developing new zirconium alloys. The corrosion resistance of Zr-0.72Sn-0.32Fe-0.14Cr-xNb alloys (x=0, 0.12, 0.28, 0.48, 0.97, mass fraction, %) was investigated in a superheated steam at 500℃ and 10.3 MPa by autoclave tests. All the plate specimens of zirconium alloys with thickness of 2.8 mm have a similar texture. The microstructure of alloys and oxide films on the corroded specimens were observed by TEM and SEM. The results showed that no nodular corrosion appeared on these alloys for 500 h exposure. The thickness of oxide layers developed on the rolling surface (SN), the surface perpendicular to the rolling direction (SR) and the surface perpendicular to the transversal direction (ST) after 500 h exposure was close to each other. There was no anisotropic corrosion resistance for these alloys. The corrosion rate of the alloys increased with the increase of Nb content after 250 h exposure when the Nb content exceeded 0.28%. In the alloy with low Nb content, the fcc-Zr(Fe, Cr)2 or fcc-Zr(Fe, Cr, Nb)2 precipitate was mainly formed, while the hcp-Zr(Fe, Cr, Nb)2 precipitate was frequently observed in the alloy with high Nb content. The corrosion resistance of Zr-0.72Sn-0.32Fe-0.14Cr-xNb alloys was improved by decreasing the Nb/Fe ratio. From a point of view for the improving corrosion resistance, the addition of Nb no more than 0.3% is recommended. © All right reserved.

Fan Q.-S.,Western Energy Material Technologies Co. | Yang Z.-B.,Nuclear Power Institute of China | Zhou J.,Western Energy Material Technologies Co. | Shi M.-H.,Western Energy Material Technologies Co. | And 2 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2016

The present paper summarized abundant crucial results about the second phase particles (SPPs) for Zr-Sn-Nb-Fe zirconium alloy in the recent years, and systematically analyzed the influence of alloy elements (Sn, Nb, Fe, etc.) on the intrinsic characteristics (crystallographic structure, microchemistries, size, distribution, etc.) of SPPs. The precipitation and evolution mechanism of SPPs were analyzed during the processing and thermal treatment process. In addition, some measures to improve the type, size and distribution of SPPs were presented in the paper. © 2016, Beijing Institute of Aeronautical Materials (BIAM). All right reserved.

Wang X.,Western Energy Material Technologies Co. | Wang X.,Northwest Institute for Nonferrous Metal Research | Li Z.,Western Energy Material Technologies Co. | Li Z.,Northwest Institute for Nonferrous Metal Research | And 10 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2013

Pipes of Zr-Sn-Nb-Fe alloy with the extruding temperature of 600, 620 and 640°C were prepared by 600°C extruding, first rolling and second rolling. The microstructure of the alloy was observed by SEM and the evolution of secondary particles and their size statistics were studied. Results show that all the second phases are distributed dispersively under different extruding conditions. The size of secondary particles is increased at higher extruding temperature. During the process of extruding and rolling, the size of the second phase decreases with the increase of processing degree, and the shape of the second phase changes from irregular to globular. Copyright © 2013 Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.

Zhou J.,Western Energy Material Technologies Co. | Li Z.,Western Energy Material Technologies Co.
Materials China | Year: 2014

Light water reactor(LWR) is a major type of nuclear power reactor in the world. Because of low neutron absorption, good corrosion resistance, and good mechanical properties, zirconium alloys are the key structural materials and functional materials for LWR power used as the cladding materials of fuel elements and other structural materials. With the development of nuclear power technology, the higher performances of the cladding material are needed, this paper reviews the research and application progress of nuclear zirconium alloy cladding and the research and development of new SiC cladding materials. In general, zirconium alloys are still the main structural materials in nuclear reactor in the coming decades, continuous R&D and improved performance of new zirconium alloys are a common goal of researchers around the world; it is necessary to increase investments and strengthen the support with human resources and financial input in order to accelerate the pace of industrialization of zirconium alloys with Chinese independent intellectual property rights; with higher melting point and better corrosion resistance requirement, SiC is a potential material for cladding of fourth generation nuclear reactor, but also needs to invest a lot of research. ©, 2014, Materials China. All right reserved.

Tian H.,University of Science and Technology Beijing | Tian H.,Western Energy Material Technologies Co. | Wang X.,University of Science and Technology Beijing | Gong W.,University of Science and Technology Beijing | And 2 more authors.
Journal of Nuclear Materials | Year: 2015

The recrystallization behavior of cold-rolled Zr-1Nb alloy was investigated by measuring the micro-Vickers hardness of the specimens annealed for various times. Different deformation reductions and annealing temperatures were coupled to study the effects of deformation and temperature on the recrystallization behavior of Zr-1Nb alloy. The results show that both large deformation reduction and high annealing temperature accelerate the recrystallization process. The microstructural evolution during recrystallization was characterized by optical microscope (OM) and transmission electron microscope (TEM) to correlate with the variation of Vickers hardness. The TEM observation also revealed the distribution of different types of Nb-containing precipitates during recrystallization. The Vickers hardness data were fitted by using the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation to derive the activation energies for recrystallization, giving the corresponding recrystallization maps. This study provides useful guidelines for the processing of a broad family of zirconium alloys based on Zr-1Nb. ©2014 Elsevier Ltd. All rights reserved.

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