The Oxidation Characteristics of the γ–γ′ Tie-Line Alloys of a Nickel-Base Superalloy
The Oxidation Characteristics of the γ–γ′ Tie-Line Alloys of a Nickel-Base Superalloy
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镍基高温合金γ-γ′联络线合金的氧化特性
DOI：
10.2320/matertrans.47.291
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发表时间：
2006
影响因子：
1.2
通讯作者：
H. Harada
中科院分区：
文献类型：
--
作者：
J. Ang;A. Sato;K. Kawagishi;H. Harada
研制了一种与镍基高温合金基体相平衡的新型粘结涂层。因此，这些涂层被称为“EQ涂层”。EQ涂层开发的第一步是检查几种高温合金的接头线。在这些高温合金中，β和β 0相互平衡，因此元素活动在这两个相中是相等的。在相同的活性下，两相之间将没有化学势差，因此没有扩散的驱动力。应用0; 0，或两者的组合作为粘合涂层候选者将确保不会形成互扩散区（IDZ）。这是期望的，因为IDZ导致总体局部机械性能劣化。在本文中，在镍基单晶合金TMS-82+的β-β 0连接线上，β 0体积分数以沿着25%的间隔从0变化到100%。在1100 ℃的环境气氛中进行了循环和等温氧化试验。所得的氧化物结构，和元素浓度分布从周围的氧化物/基板界面，通过耗尽区，到健全的基板，进行了分析，通过SEM/EDX。所有样品开始时具有相同的元素活性;因此，在氧化开始时，预期所有样品形成相同的氧化物结构。然而，实验表明，这些样品形成了截然不同的氧化物结构，并且具有最好的抗高温氧化性。
A novel family of bond coats designed to be in EQuilibrium with their nickel-base superalloy substrates has been developed. These coatings have hence been termed ‘EQ coatings’. The first step taken for EQ coating development was to examine the � –� 0 tie-lines of several superalloys. In these superalloys, � and � 0 are in equilibrium with each other, and elemental activities are thus equal in these two phases. With equal activities, there will be no chemical potential differences between the two phases, and there is thus no driving force for diffusion. Applying �; � 0 , or a combination of both as bond coat candidates will ensure that no inter-diffusion zone (IDZ) will form. This is desirable, as IDZ causes gross local mechanical property degradation. In this paper, the � 0 volume fraction was varied from 0 to 100% at 25% intervals along the � –� 0 tie-line of a nickel-base single-crystal alloy, TMS-82+. Cyclic and isothermal oxidation tests were conducted at 1100 � C in ambient atmosphere. The resultant oxide structures, and the element concentration profiles from around the oxide/substrate interface, through the depletion zone, into the sound substrate, were analyzed by SEM/EDX. All samples started with the same element activities; hence, at the onset of oxidation, all samples were expected to form the same oxide structure. However, experiments showed that the specimens formed vastly different oxide structures, and that � 0 had the best resistance against high temperature oxidation.