Effects of Grain Refinement and Predeformation Impact by Severe Plastic Deformation on Creep in P92 Martensitic Steel
Effects of Grain Refinement and Predeformation Impact by Severe Plastic Deformation on Creep in P92 Martensitic Steel
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剧烈塑性变形的晶粒细化和预变形影响对 P92 马氏体钢蠕变的影响
DOI：
10.1002/adem.201900448
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发表时间：
2019
影响因子：
3.6
通讯作者：
Svobodova Marie
中科院分区：
文献类型：
--
作者：
Sklenicka Vaclav;Kral Petr;Dvorak Jiri;Takizawa Yoichi;Masuda Takahiro;Horita Zenji;Kucharova Kveta;Kvapilova Marie;Svobodova Marie
对一种先进的马氏体铁素体抗蠕变P92钢(ASME级92)进行了蠕变试验，以评价其经强塑性变形(SPD)即高压扭转和高压滑动处理后的细化效果和预变形影响。恒载荷拉伸蠕变试验是在60 0 °C的Ar气氛中，在50~2 0 0 Mpa的应力范围内进行的。结果表明，在相同的蠕变载荷条件下，经SPD处理后的超细晶组织状态与粗晶状态相比，具有更高的最低蠕变速率和蠕变断裂塑性，但蠕变寿命明显缩短。粗晶态和超细晶状态之间的显著差异可以用不同的变形机制来解释；粗晶状态下的蠕变行为由位错在晶内的攀移控制，而超细晶状态下的蠕变可以解释为高角度晶界自由位错的动态恢复和晶界中介的变形过程的协同作用。
Creep testing is conducted on an advanced martensitic‐ferritic creep‐resistant P92 steel (ASME Grade 92) to evaluate the effects of grain refinement and the predeformation impact after processing by severe plastic deformation (SPD), namely, by high‐pressure torsion and high‐pressure sliding. Constant‐load tensile creep tests are carried out in an argon atmosphere at 600 °C and under an applied stress ranging from 50 to 200 MPa. The results show that under the same creep loading conditions, the ultrafine‐grained (UFG) microstructure states after SPD processing exhibit higher minimum creep ratemand creep fracture plasticity, but significantly shorter creep lives in comparison with the coarse‐grained (as‐received) state of the steel. These distinct differences between the coarse‐grained and UFG states are explained by the different deformation mechanisms that operate; creep behavior in a coarse‐grained state is controlled by the intragranular climb of dislocations, while creep in UFG states can be interpreted as the synergistic action of the dynamic recovery of free dislocations at high‐angle grain boundaries and grain boundary‐mediated deformation processes.