摘要
在546℃下,对电厂用关键材料P91钢进行应力控制的蠕变—疲劳交互作用下试验。分别讨论平均应力和应力幅对断裂时间的影响,分析断口形貌与韧窝脱粒成分,断口裂纹金相,获得P91钢蠕变—疲劳交互作用下断裂机制与断裂特性。研究结果表明,由于微观裂纹的闭合,P91钢蠕变—疲劳交互作用寿命随着下保载的时间增加而增加。当平均应力远小于应力幅时,试样主要表现为疲劳断裂,当平均应力与应力幅相等时,试样为蠕变疲劳共同作用下的断裂特征,当平均应力远大于应力幅时,断裂特征为蠕变断裂。通过断口金相分析,试样断口裂纹均为穿晶断裂。对断口韧窝的脱粒成分研究,脱粒为氧化物。研究结果为P91钢蠕变—疲劳断裂机制分析提供理论和实验基础。
At 546 ℃, stress controlled creep-fatigue interaction test for P91 was investigated. Effect of mean stress on fracture life, fracture pattern and constituent of dimple particle, fracture crack metallic phase were discussed and analyzed respectively. Mechanism and performance of the fracture were obtained for P91 steel under creep-fatigue interaction. The research results show that, because of closure of the micro-crack in P91 steel, the creep-fatigue life of P91 steel is increasing with bottom holding time adding. When the mean stress is less than the stress amplitude much more, fatigue fracture is shown in the P91 specimens. As the mean stress is equal to stress amplitude, creep and fatigue dominate the fracture of specimens. When the mean stress is greater than stress amplitude, the feature of specimens is creep fracture. By the analysis of constituent of dimple particle in the fracture, the particle is oxide. The research results can provide the theoretical and experimental base for fracture mechanism analysis of P91 steel under creep-fatigue interaction.
出处
《机械强度》
CAS
CSCD
北大核心
2012年第6期886-891,共6页
Journal of Mechanical Strength
基金
苏州热工研究院博士后基金
国家科技重大专项(2011ZX06004-002)资助~~
