LI Bei WU Shuangxia LI Dianchen Baotou Research Institute of Rare Earth Ministry of Metallurgical Industry
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Baotou
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ChinaMA Ruzhang University Science and Technology Beijing
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Beijing
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China Baotou Research Institute of Rare Earth
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Ministry of Metallurgical Industry
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Baotou 014010
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China
金属学报(英文版)
A high temperature embrittlement occures in Fe-15Cr-4AI and Fe-20Cr-4Al alloys treated over 1000 C.It is caused mainly by 475℃ brittleness during cooling.When a secondary treatment at 500℃ was conducted,the 475℃ brittleness developed very rapidly.After only 15 rain of the treating,little plasticity was remained for all samples pretreuted at the temper- atures over 1000℃ and cooled in water.However,no 475℃ brittleness was generated when pretreating temperature was below 1000℃,Addition of Yttrium can inhibit not only grain growth,but also 475℃ brittleness.For the alloys with 0.2—0.4 wt-%Y,after treating at 800—1300℃,the plasticity did not decrease and the properties of furnace cooled samples were not lower than those of water cooled samples.
关键词:
Fe-Cr-Al alloy
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LI Bei WU Shuangxia MENG Guang'en JIANG Liping PANG Wenjie Baotou Research Institute of Rare Earth
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Baotou
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China Baotou Research Institute of Rare Earth
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P.O.Box 131
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Baotou 014010
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China
金属学报(英文版)
With the increase of Y content in the Fe-20Cr-4AI-Y alloy,the uniform deformability of tensile specimens was found to be slightly decreased,as well as,the fracture strength and re- duction after necking remarkably dropped.This seems to be dependent upon the brittle phase containing Y.The behaviour of Y-containing phase may be improved by adjusting the metallurgical technological process.
关键词:
Fe-Cr-A1 alloy
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稀土学报(英文版)
The microstructural characteristics of syntactic polycrystal in the calcium-rare earth fluorocarbonate minerals from Southwest China have been studied by means of selected area electron diffraction and high resolution electron microscopy(HREM). The complication of the heterogeneous fabric of the minerals have been revealed by HREM. The results show that the crystal structure of the minerals was formed by a disorder stacking of the unit layers of bast-naesite and synchisite in the calcium rare earth fluorocarbonate minerals along (c) over right arrow direction. The stacking fault and other crystal defects in the syntactic polycrystal have been discussed.
关键词:
rare earths;calcium rare earth fluorocarbonate mineral;syntactic;intergrowth;high resolution electron microscopy
Journal of Physics D-Applied Physics
A comprehensive review is given of recent advances in the study of metastable phases in rare-earth permanent magnets. The relations between the structures of the metastable and equilibrium phases and the transformations from the former to the latter are discussed. The formation of the phases is found to depend on the difference between the symmetries of the metastable and equilibrium phases. The magnetic properties of the metastable-phase rare-earth permanent magnets synthesized by various processes, such as mechanical alloying, mechanical milling, rapid quenching, hydrogenation, disproportionation, desorption and recombination, solid-state reaction, solid-gas reaction, self-flux and sputtering, are compared. The main conclusion of this article is that searching for new metastable phases with high magnetic performance will be one of the most active directions in the research on rare-earth permanent magnets.
关键词:
fe-c alloys;disproportionation-desorption-recombination;solidified;sm-fe;r = nd;high-coercivity;magnetocrystalline anisotropy;intermetallic compounds;remanence enhancement;crystal-structure;high-performance
X.K. Tao
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X.Cong
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R.S. Peng
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J.Liu and Z.Y. Liu Tianjin Institute of Technology
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Tianjin 300191
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China
金属学报(英文版)
This paper investigates the effect of rare earth elements on the kinetic process, microstructure and mechanical properties of vanadization in borax bath. The results show that addition of rare earth elements to vanadizing agent has obvious catalytic effect on the rate of vanadization, which has been enchanced by 30%. The wear and corrosion resistance of vanadium carbide layer were prompted by the addition of rare earth to the agent. Through increasing vanadium potential of the agent, activating the surface of workpieces and decreasing the activation energy of diffusion of carbon, rare earth elements accelerate the rate of vanadization process.
关键词:
rare earth elements
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