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我们用金相、电子探针、透射电镜和离子探针等实验技术,对比研究了含钇和不合钇的Fe25Cr-5Al电热合金的晶界行为。研究结果表明:钇几乎都集中在Y(Fe,Al,Cr)_9相里,其中铝含量高于基体。而钇在合金内固溶甚微。铁铬铝合金中添加钇,增加了合金的位错密度,促进了铝选择氧化;Y(Fe,Al,Cr)_9相沿晶界氧化,形成钇铝复合氧化物,对氧化膜起“钉扎”作用,弥散分布的内氧化物质点引起的空位陷阱效应,改善了合金氧化膜的粘附性;氧化钇质点和氧化时沿晶界形成的钇铝复合氧化物,提高了合金丝的高温强度。因此,钇可以大幅度提高铁铬铝电热合金循环氧化寿命。
We have studied the grain boundary behavior of Fe25Cr-5Al electric alloys containing yttrium and non-yttrium using metallographic, electronic, TEM and ion-probe techniques. The results show that almost all yttriums are concentrated in Y (Fe, Al, Cr) _9 phase, in which the content of aluminum is higher than that of matrix. The yttrium in the alloy solution is very small. The addition of yttrium to the iron-chromium-aluminum alloy increases the dislocation density of the alloy and promotes the selective oxidation of aluminum. The Y (Fe, Al, Cr) _9 phase is oxidized along the grain boundaries to form the yttrium aluminum composite oxide, ", The vacancy trap effect caused by the dispersed oxide inner points improves the adhesion of the alloy oxide film; the yttrium oxide particles and the yttrium aluminum composite oxide formed along the grain boundaries during oxidation improve the high temperature strength of the alloy wire . Therefore, yttrium can significantly improve the cycle oxidation life of iron-chromium aluminum electric alloy.