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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QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing
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Beijing
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China
金属学报(英文版)
The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.
关键词:
stress corrosion cracking
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