【摘要】 研究了钇、镧、铈及混合稀土金属对801和31.0合金瞬时拉伸性能、高温持久性能、高温抗氧化性能及抗硫酸铝溶液腐蚀性能的影响。用金相显微镜、扫描电镜、电子探针、离子探针和X-射线衍射研究了氧化膜的形态、结构和组成。测定了801合金在硫酸铝溶液中的极化曲线。结果表明,稀土元素能提高310和801合金的持久寿命;明显改善其高温抗氧化性能;对室温瞬时性能影响很小。结果还表明,稀土元素使801合金的点蚀倾向增大;降低801合金在硫酸铝溶液中的耐腐蚀性。更多还原

【Abstract】 In this paper the effect of Y, La, Ce and the mischmetal on the mechanical and chemical properties of 801 and 310 alloys has been studied, including tensile properties at room temperature, rupture life and oxidation resistance at high temperature as well as corrosion resistance in industrial aqueous solution of Al₂（SO₄）₃. The morphology, structure and composition of oxide scale have been investigated by optical microscopy, SEM, electron probe microanalysis, ion probe microanalysis and X-ray diffraction. The polarization curves of 801, 801+Y, 801+La and 801+Cc alloys in industrial aqueous solution of Al₂（SO₄）₃ have also been determined.Results show that when the rare-earth elements arc added to 310 and 801 alloys, the rupture lives at 900℃ increase by 50-100％, but almost no change in the tensile properties is observed at room temperature. As the rare-earth elements can accelerate the deffusion of Cr in γ matrix, formation of Cr₂O₃ scales on the surface of alloy is accerlcratcd, and the bond energy of Cr⁺³ in Cr₂O₃ scale is incrcarcd, forming rare earth oxides in needle shape at the scale/alloy interface, so that the oxide film is capable to adhere tightly to the matrix metal, and in such a way the oxidation resistance of the alloys at 750～1050℃ is greatly improved. Results of the determination of polarization curves show that the addition of rare-earth elcrncnts into the alloys studied can increase the potential and current of passivation, in consequence, the passive corrosion current would increase, and the passive film on the allot surface is difficult to form, so that the corrosion resistance of 801 alloy in aqueous solution of Al₂（SO₄）₃ is reduced. The rare-earth metals causing such deteriorated effect arc in the following order of magnitude: Cc, La and Y. Moreover, most of the rarc-earth metals in the matrix form inclusions, which act as cathode in the Al₂（SO₄）₃ solution, and would accelerate the pittfng corrosion in thealloys.更多还原