Evolution of microstructure and deformation resistance in creep of tempered martensitic 9-12%Cr-2%W-5%Co steels
Evolution of microstructure and deformation resistance in creep of tempered martensitic 9-12%Cr-2%W-5%Co steels
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DOI：
10.1016/j.actamat.2006.02.038
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发表时间：
2006-06-01
期刊：
影响因子：
9.4
通讯作者：
Chakravartty, J. K.
中科院分区：
文献类型：
--
作者：
Agamennone, R.;Blum, W.;Chakravartty, J. K.
通过电子显微镜对四种用2%钨和5%钴改性的9 - 12%铬回火马氏体钢在923 K下蠕变过程中的微观结构演变进行了量化。证实了亚晶粒随应变朝着与应力相关的稳态粗化。就M23C6（M：金属元素，X：N，C）和拉弗斯相(Fe,Cr)₂(W,Mo)而言，析出相结构的演变相似，但就含钒析出相而言则有很大差异。低温回火促进钒以M2X而不是VX的形式析出。这似乎是导致初始高抗蠕变性异常快速下降的关键因素。提出亚晶粒内部小的含钒析出相的溶解以及相应的沉淀强化损失是这种下降的原因。溶解是由M2X析出相的快速粗化以及在亚晶粒边界处Z相的析出引起的。提出亚晶粒边界处的大M2X析出相是Z相的形核位点。（c）2006 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
The microstructural evolution during creep at 923 K of four tempered martensite 9-12%Cr-steels modified with 2%W and 5%Co was quantified by electron microscopy. Coarsening of subgrains with strain towards the stress dependent steady state was confirmed. The evolution of the precipitate structure is similar with regard to M23C6 (M: metallic element, X: N, C) and Laves phase (Fe,Cr)(2)(W,Mo) but differs strongly with regard to V-bearing precipitates. Low temper temperatures promote precipitation of V as M2X instead of VX. This appears to be critical in causing anomalously fast breakdown of initially high creep resistance. Dissolution of small V-bearing precipitates and corresponding loss of precipitation hardening in the subgrain interior is proposed to be the reason for this breakdown. The dissolution is caused by fast coarsening of M2X precipitates and precipitation of Z-phase at subgrain boundaries. Large M2X precipitates at subgrain boundaries are proposed to be nucleation sites of Z-phase. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.