Creep deformation and rupture behaviour of 9Cr–1W–0.2V–0.06Ta Reduced Activation Ferritic–Martensitic steel
Creep deformation and rupture behaviour of 9Cr–1W–0.2V–0.06Ta Reduced Activation Ferritic–Martensitic steel
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DOI：
10.1016/j.msea.2011.10.112
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发表时间：
2012-01
期刊：
影响因子：
6.4
通讯作者：
J. Vanaja;K. Laha;R. Mythili;K. S. Chandravathi;S. Saroja;M. D. Mathew
中科院分区：
文献类型：
--
作者：
J. Vanaja;K. Laha;R. Mythili;K. S. Chandravathi;S. Saroja;M. D. Mathew
本文介绍了国产聚变堆用9 Cr-1 W-0.2V-0.06Ta低活化铁素体-马氏体（RAFM）钢的蠕变变形和持久行为。蠕变研究在773，823和873 K在100- 300 MPa的应力范围内进行。钢的蠕变变形被发现进行与相对较短的第一政权随后由一个扩展的第三政权，几乎没有第二政权。材料的最小蠕变速率随外加应力的变化符合幂律关系，σ m=Aσn，应力指数n值随温度的升高而减小。最小蠕变速率与持久寿命的乘积符合修正的Monkman-Grant关系。第三变形阶段开始的时间与断裂寿命成正比。TEM研究表明，相对较大的变化，马氏体亚结构和粗化的沉淀物在钢中的蠕变暴露相比，热暴露。微观结构退化是导致蠕变第三阶段扩展的主要原因，其损伤容限因子λ大于2.5。考虑到蠕变暴露时材料的微观结构不稳定性，最小蠕变速率随应力和温度的变化不服从引用Lagneborg和Bergman的背应力概念修正的多恩方程。
This paper presents the creep deformation and rupture behaviour of indigenously produced 9Cr–1W–0.2V–0.06Ta Reduced Activation Ferritic–Martensitic (RAFM) steel for fusion reactor application. Creep studies were carried out at 773, 823 and 873K over a stress range of 100–300MPa. The creep deformation of the steel was found to proceed with relatively shorter primary regime followed by an extended tertiary regime with virtually no secondary regime. The variation of minimum creep rate of the material with applied stress followed a power law relation, έm=Aσn, with stress exponent value ‘n’ decreasing with increase in temperature. The product of minimum creep rate and creep rupture life was found to obey the modified Monkman–Grant relation. The time to onset of tertiary stage of deformation was directly proportional to rupture life. TEM studies revealed relatively large changes in martensitic sub-structure and coarsening of precipitates in the steel on creep exposure as compared to thermal exposure. Microstructural degradation was considered as the prime cause of extended tertiary stage of creep deformation, which was also reflected in the damage tolerance factor λ with a value more than 2.5. In view of the microstructural instability of the material on creep exposure, the variation of minimum creep rate with stress and temperature did not obey Dorn's equation modified by invoking Lagneborg and Bergman's concepts of back stress.