中文摘要：

采用纳米压入方法对核电站一回路主管道的双相不锈钢材料热老化行为进行定量研究。通过对单独的铁素体相和奥氏体相的纳米压入实验,得到随着老化时间的增加,两者在相同压入深度时的压入载荷增加;根据动态测试技术得到的纳米硬度增加,表现为强度提高;而纳米压入塑性变形能降低,表现为韧性降低;并且不同老化时间下铁素体相的强度和韧性都要高于奥氏体相。通过微观组织结构研究发现,老化时间增加导致铁素体相内产生调幅分解,生成的富Cr-α′相引起位错的钉扎和聚集,使铁素体内部应力水平和三向应力比提高,导致强度提高而韧性下降。

英文摘要：

The thermal aging effect on the duplex stainless steel from the primary pipe of the PWR （pressurized water reactor） is investigated with the nano-indentation method.From the nano-indentation tests on the ferrite and austenite phases,it is found that,the nano-indentation loads of both phases on the same nano-indentation depth increase which means the strengths increase.With the CSM（continue stiffness measurement） technique,the nano-hardness increases while the nano-indentation plastic energy decreases with the increment of the aging time.The strength and the toughness of the ferrite phase are higher than those of the austenite phase.The Cr rich-α′ phases from the spinodal decomposition in the ferrite phase,cause the piling up of the dislocations and increase the stress level and the stress triaxiality which will increase the strength and decrease the toughness of the duplex stainless steel.