High-temperature strength characterization of advanced 9Cr-ODS ferritic steels
High-temperature strength characterization of advanced 9Cr-ODS ferritic steels
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DOI：
10.1016/j.msea.2008.04.126
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发表时间：
2009-06
期刊：
影响因子：
6.4
通讯作者：
S. Ukai;S. Ohtsuka;T. Kaito;H. Sakasegawa;N. Chikata;S. Hayashi;S. Ohnuki
中科院分区：
文献类型：
--
作者：
S. Ukai;S. Ohtsuka;T. Kaito;H. Sakasegawa;N. Chikata;S. Hayashi;S. Ohnuki
氧化物弥散强化 (ODS) 铁素体钢是先进快堆燃料元件最有前途的候选材料，在 973K 时具有出色的蠕变强度。 9Cr-ODS 铁素体钢的优异蠕变性能归因于非平衡相（称为残余铁素体）的形成。通过纳米压痕测量，室温下残余铁素体本身的屈服强度高达 1360MPa。通过最大限度地减少马氏体相变引起的包边界数量，也可以提高蠕变强度。蠕变应变发生的应力低于晶内区域变形所需的应力，晶内区域变形通过纳米尺寸氧化物颗粒和位错之间的相互作用而得到加强；这是通过在较弱区域（例如晶粒边界和包边界）处滑动而发生的。研究发现，9Cr-ODS 铁素体钢表现为纤维复合材料，包含较硬的残余铁素体和较软的回火马氏体。
Oxide dispersion strengthened (ODS) ferritic steels, which are the most promising candidate materials for advanced fast reactor fuel elements, have exceptional creep strength at 973K. The superior creep property of 9Cr-ODS ferritic steels is ascribed to the formation of a nonequilibrium phase, designated as the residual ferrite. The yield strength of the residual ferrite itself has been determined to be as high as 1360MPa at room temperature from nanoindentation measurements. The creep strength is also enhanced by minimizing the number of packet boundaries induced by the martensitic phase transformation. The creep strain occurs at a lower stress than that necessary for the deformation of the intragrain regions, which are strengthened by an interaction between nanosize oxide particles and dislocations; this occurs by sliding at weaker regions such as at the grain boundaries and packet boundaries. It is found that 9Cr-ODS ferritic steels behave as fiber composite materials comprising the harder residual ferrite and the softer tempered martensite.