Mechanisms of Breakaway Oxidation and Application to a Chromia-Forming Steel
Mechanisms of Breakaway Oxidation and Application to a Chromia-Forming Steel
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铬形成钢的脱离氧化机理及其应用
DOI：
10.1023/a:1018855914737
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发表时间：
1999
影响因子：
2.2
通讯作者：
T. Gilmour
中科院分区：
文献类型：
--
作者：
H. Evans;A. Donaldson;T. Gilmour
本文从两种可能的机制描述了分离氧化或化学失效，并将其应用于20Cr-25Ni奥氏体钢的失色形成行为。这两种机制都与铬的选择性氧化引起的损耗有关，损耗剖面的定量建模用于确定主要的化学失效机制作为温度的函数。当合金中在氧化物-金属界面处的铬浓度小于含铬平衡时，就会发生本征化学失效（InCF）。这发生在高温下，通常高于1390k，但合金易受这种形式失效影响的温度随着合金晶粒尺寸的减小而增加。在较低温度下，化学失效与整个试样截面上铬的普遍损耗有关，低于该水平，如果表层受损，则不会发生愈合铬层的重新形成。在这种情况下，故障被称为机械诱导化学故障（MICF）。
Breakaway oxidation or chemical failure has beendescribed in this paper in terms of two possiblemechanisms and applied to the behavior of achromia-forming 20Cr-25Ni austenitic steel. Bothmechanisms relate to the depletion of chromium arisingfrom its selective oxidation and quantitative modelingof the depletion profile is used to identify thedominant chemical-failure mechanism as a function oftemperature. Intrinsic Chemical Failure (InCF) develops whenthe chromium concentration within the alloy at theoxide-metal interface is less than that in equilibriumwith chromia. This occurs at high temperatures, typically above 1390 K, but the temperature atwhich the alloy becomes susceptible to this form offailure increases as the alloy grain size decreases. Atlower temperatures, chemical failure is associated with the general depletion of chromium acrossthe specimen section to a level below which reformationof a healing chromia layer will not occur, should thesurface layer become damaged. In this regime, failure is termed Mechanically Induced ChemicalFailure (MICF).