中文摘要：

为探索实际服役环境对核电主管道用双相不锈钢热老化脆化的影响，在空气及模拟工况两种不同介质环境对核电一回路主管道用Z3CN20-09M双相不锈钢进行350℃加速热老化，采用微型杯突试验（SPT）测定两种环境下热老化不同时间后的双相钢力学性能．使用扫描电镜（SEM）对微型杯突试样断口形貌进行观察，分析热老化环境及时间对其断裂机理的影响．试验结果表明：在热老化的初期（0～2000h），双相不锈钢的微型杯突屈服强度、最大强度和断裂能都有一个明显的峰值，随着热老化时间的延长，微型杯突屈服和最大强度值缓慢增长，而断裂能则缓慢减少，双相不锈钢逐渐向脆性转变；t检验可知，不同环境对热老化脆化无显著影响．随着热老化时间延长，断口的韧窝数量减少，尺寸逐渐减小．热老化的时长是影响材料性能的主要原因，环境因素对热老化脆化的影响并不显著．

英文摘要：

The thermal aging of duplex stainless steel of nuclear power primary coolant piping in the actual environment is explored. The Z3CN20-09M duplex stainless steel was treated by thermal aging in the air or simulation conditions at 350 ℃. The mechanical properties of the steel after two different thermal aging was measured by small punch test. The fracture morphology of the specimen was observed by scanning electron microscopy （SEM）, and the influence of the environment and time on the fracture mechanism was analyzed. The results show： At the beginning of the thermal aging （0-2 000 h）, the yield strength,the maximum strength and the fracture energy of the duplex stainless steel＇s SPT have a significant peak;With the increase of the thermal aging time, the yield strength and maximum strength slowly increase,but the fracture energy decreases, the steel gradually transformes into brittle materials. The t-test shows that there is no significant effect on thermal aging embrittlement in different environments. The SEM analysis shows that the number and the size of dimples is reduced with the deepening of thermal ageing, The duration of thermal aging is the main reason for the performance of the material,and there is no significant effect on thermal aging embrittlement in different environments.