摘要
在620℃下对X12CrMoWVNbN10-1-1钢进行不同应力比(0.2~0.4)和保载时间(0.3~1.5 h)下的载荷控制的高位保载蠕变-疲劳试验,对其蠕变-疲劳交互作用及断裂机理进行了分析。结果表明:试验钢的蠕变-疲劳寿命与保载时间呈指数关系,保载时间越长,应力比对蠕变-疲劳寿命的影响越小;从应变角度定义的蠕变-疲劳交互作用因子能够很好地反映稳定阶段的真应力-真应变迟滞回线与蠕变-疲劳寿命的相互作用;试验钢的蠕变-疲劳断裂模式为韧性断裂;当保载时间较短(0.3,0.5 h)时,疲劳损伤抑制蠕变损伤,损伤主要受循环中的疲劳载荷控制,断口中韧窝由疲劳主导作用下的晶界滑移变形引起;当保载时间较长(1.0,1.5 h)时,疲劳损伤促进蠕变损伤,损伤主要受与时间有关的蠕变载荷控制,断口中韧窝由夹杂物或第二相颗粒脱落所致。
The creep-fatigue tests with load holding at maximum stress controlled by load with different stress ratios(0.2-0.4)and holding times(0.3-1.5 h)of X12CrMoWVNbN10-1-1 steel at 620℃were carried out,and the creep-fatigue interaction and fracture mechanism of the steel were analyzed.The results show that the creep-fatigue life of the test steel had exponent relation with the holding time.The longer the loading time,the less the influence of stress ratio on creep-fatigue life.The creep fatigue interaction factor defined from the view of strain could well reflect the interaction between the true stress-true strain hysteretic curve and the creep fatigue life in the stable stage.The creep-fatigue fracture mode of the test steel was ductile fracture.When the holding time was short of 0.3,0.5 h,the fatigue damage suppressed creep damage,and the damage was mainly controlled by cyclic fatigue load;the dimples on the fracture were caused by crystal boundary slide controlled by fatigue.When the holding time was long enough of 1.0,1.5 h,the fatigue damage promoted creep damage,and the damage was mainly controlled by timerelated creep load;the dimples on the fracture were caused by detachment of inclusions or second phase particles.
作者
畅旭兵
王勇
林琳
纪冬梅
CHANG Xubing;WANG Yong;LIN Lin;JI Dongmei(Guangdong Electric Yuehai Power Generation Co.,Ltd.,Jieyang 515223,China;Xi'an Thermal Power Research Institute Co.,Ltd.,Xi'an 710054,China;School of Energy and Mechanical Engineering,Shanghai University of Electric Power,Shanghai 200090,China)
出处
《机械工程材料》
CAS
CSCD
北大核心
2023年第1期34-41,47,共9页
Materials For Mechanical Engineering
基金
上海市自然科学基金资助项目(19ZR1420300)。
