Strain-induced coarsening of nanoscale precipitates in strength enhanced high Cr ferritic steels
Strain-induced coarsening of nanoscale precipitates in strength enhanced high Cr ferritic steels
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DOI：
10.1016/j.msea.2011.10.105
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发表时间：
2012-01-15
期刊：
影响因子：
6.4
通讯作者：
Igarashi, Masaaki
中科院分区：
文献类型：
--
作者：
Armaki, Hassan Ghassemi;Chen, Ruiping;Igarashi, Masaaki
应变引起的沉淀粗化（主要是 M23C6）已在几种类型的 Gr 中进行了研究。 122，GR。 92 和 Gr。 91 钢在各种蠕变条件下。应变引起的析出物粗化应分别在高应力和短期蠕变区域（或称为“H”）和低应力长期蠕变区域（或称为“L”）和低应力区域分别进行评估，其中析出物和亚晶粒是热稳定的，在长期蠕变区域（或称为“L”），其中析出物和亚晶粒出现热粗化。蠕变塑性变形不会加速短期蠕变区“H”中初级和次级蠕变区期间析出物的粗化。然而，M23C6 析出物的粗化发生在加速蠕变区域，并且随着施加应力的减小而增加。长期区域“L”的开始伴随着M23C6析出物的热粗化以及在二次和加速蠕变区域期间以及可能在非常低的蠕变应力下的初级蠕变区域中M23C6析出物的应变诱导的粗化。在长期区域“L”中，位错亚结构的恢复同时受到蠕变塑性变形和析出物钉扎力的控制。另一方面，析出物的粗化是由于析出物的热粗化和应变引起的粗化两者造成的。事实上，析出相的稳定性是抑制长期区域“L”中亚晶回复的最重要因素，而不是短期蠕变区域“H”。在长期区域“L”中，由于较高的蠕变温度或/和较长的蠕变断裂寿命，亚晶粒和M23C6析出物的更大热恢复导致M23C6析出物更大的应变诱导粗化。 (C) 2011 Elsevier B.V. 保留所有权利。
Strain-induced coarsening of precipitates, mainly M23C6, has been studied in several types of Gr. 122, Gr. 92 and Gr. 91 steels in a wide range of creep conditions. Strain-induced coarsening of precipitates should be separately evaluated in high stress and short-term creep region (or called "H"), where precipitates and subgrains are thermally stable, and low stress in long-term creep region (or called "L"), where thermal coarsening of precipitates and subgrains appear. Creep plastic deformation does not accelerate the coarsening of precipitates during the primary and secondary creep regions in short-term creep region "H". However, the coarsening of M23C6 precipitates occurs during the acceleration creep region and increases with decreasing of applied stress. The onset of long-term region "L" is accompanied by the thermal coarsening of M23C6 precipitates as well as strain-induced coarsening of M23C6 precipitates during secondary and acceleration creep regions and maybe in primary creep region under very low creep stress. In long-term region "L", recovery of the dislocation substructure is controlled simultaneously by creep plastic deformation and pinning force from precipitates. On the other hand, the coarsening of precipitates is due to both thermal coarsening and strain-induced coarsening of precipitates. In fact, the stability of precipitates is the most important factor for the suppression of subgrain recovery in long-term region "L" rather than short-term creep region "H". In long-term region "L", greater thermal recovery of subgrains and M23C6 precipitates due to higher creep temperature or/and longer creep rupture life results in greater strain-induced coarsening of M23C6 precipitates. (C) 2011 Elsevier B.V. All rights reserved.