High-temperature oxidation behaviour of novel Co-Al-W-Ta-B-(Mo, Hf, Nb) alloys with a coherent γ/γ'–dominant microstructure
High-temperature oxidation behaviour of novel Co-Al-W-Ta-B-(Mo, Hf, Nb) alloys with a coherent γ/γ'–dominant microstructure
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DOI：
10.1016/j.pnsc.2016.11.005
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发表时间：
2016-12
期刊：
影响因子：
--
通讯作者：
Jiangbo Sha
中科院分区：
文献类型：
--
作者：
Fei Zhong;Fei Fan;Shusuo Li;Jiangbo Sha
在本工作中，在Co-9Al-9W-2Ta-0.02B合金(以下分别称为2Mo、2Nb和2Hf合金，原始合金记为0Me合金)中，用2at%Mo、2 at%Nb和2 at%Hf取代了等量的W。研究了添加Mo、Hf和Nb对Co-9Al-9W-2Ta-0.02B合金在800℃和900℃恒温暴露100h后的抗氧化性、氧化膜演化和失效机制的影响。结果表明，Mo、Hf和Nb的加入降低了Co-9Al-9W-2Ta-0.02B合金的抗氧化性，而2Mo合金的抗氧化性最差，这是由于氧化膜的严重剥落所致。随着氧化温度和添加元素(Mo、Hf、Nb)的不同，由外层Co3O4+CoO层、富Al、W、Ta的中间复合氧化层和附着在γ衬底上的γ/γ/针状Co3W层组成的氧化膜逐渐形成，在γ/针状Co3W层内观察到连续或不连续的Al2O3层和弥散分布的Al2O3点或片状结构。2Mo合金氧化膜中挥发性MoO_3的形成加剧了氧化产物的剥落，导致剥落严重，抗氧化性差。
In this work, 2 at% Mo, 2 at% Nb and 2 at% Hf were substituted for the same amount of W into a Co-9Al-9W-2Ta-0.02B alloy (hereafter referred as to 2Mo, 2Nb and 2Hf alloys, respectively, while the original alloy is denoted as 0Me alloy). The effect of the Mo, Hf and Nb additions on the isothermal oxidation resistance, oxide scale evolution and failure mechanism, of the Co-9Al-9W-2Ta-0.02B alloy when exposed at 800 °C and 900 °C for 100 h was investigated. It was found the Mo, Hf and Nb additions degraded the oxidation resistance of the Co-9Al-9W-2Ta-0.02B alloy, while the 2Mo alloy always displayed the poorest oxidation resistance, resulted from heavy spallation of the oxide scale. An oxide scale composed of an outer Co3O4+CoO layer, a middle complex oxide layer enriched with Al, W and Ta, and a γ/needle-like Co3W zone adhering to the γ/γ' substrate was gradually formed; moreover, a continuous or discontinuous Al2O3layer and dispersive Al2O3dots or slices were observed within the γ/needle-like Co3W zone, depending on the oxidation temperature and added elements (Mo, Hf and Nb). The formation of volatile MoO3in the oxide scale of the 2Mo alloy enhance the exfoliation of the oxide products, resulting in severe spallation and poor oxidation resistance.
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影响因子：
8.3
作者：
H.-Y. Yan;V. Vorontsov;D. Dye
通讯作者：
H.-Y. Yan;V. Vorontsov;D. Dye
影响因子：
8.3
作者：
L. Klein;B. V. Bartenwerffer;M. Killian;P. Schmuki;S. Virtanen
通讯作者：
L. Klein;B. V. Bartenwerffer;M. Killian;P. Schmuki;S. Virtanen
影响因子：
6
作者：
A. Bauer;S. Neumeier;F. Pyczak;M. Göken
通讯作者：
A. Bauer;S. Neumeier;F. Pyczak;M. Göken
影响因子：
4.4
作者：
H.-Y. Yan;V. Vorontsov;D. Dye
通讯作者：
H.-Y. Yan;V. Vorontsov;D. Dye
DOI：
10.1016/0956-7151(92)90195-k
发表时间：
1992-01-01
期刊：
ACTA METALLURGICA ET MATERIALIA
影响因子：
--
作者：
POLLOCK, TM;ARGON, AS
通讯作者：
ARGON, AS