CAJ | 학술논문

对TP347H不锈钢进在550℃下纯疲劳及550℃下的蠕变-疲劳交互下的微观组织演化及疲劳寿命变化进行研究。断口的扫描电镜形貌表明在蠕变-疲劳交互下存在高温动态回复，使得蠕变-疲劳断口未形成二次裂纹与解理面，而在纯疲劳下存在较多二次裂纹与解理面；透射电镜形貌表明在蠕变疲劳交互下金属内部局部会形成清晰的位错墙和位错胞结构，错增殖密度相对于纯疲劳也大大降低，此时材料的循环软化特征明显，因此蠕变-疲劳交互会导致材料的疲劳寿命显著降低。对不同应变幅下TP347H的蠕变-疲劳寿命试验证明不同应变幅下TP347不锈钢的蠕变-疲劳循环寿命相对于纯疲劳条件下都有降低，降低的程度随应变幅的增加而增大。
대TP347H불수강진재550℃하순피로급550℃하적연변-피로교호하적미관조직연화급피로수명변화진행연구。단구적소묘전경형모표명재연변-피로교호하존재고온동태회복，사득연변-피로단구미형성이차렬문여해리면，이재순피로하존재교다이차렬문여해리면；투사전경형모표명재연변피로교호하금속내부국부회형성청석적위착장화위착포결구，착증식밀도상대우순피로야대대강저，차시재료적순배연화특정명현，인차연변-피로교호회도치재료적피로수명현저강저。대불동응변폭하TP347H적연변-피로수명시험증명불동응변폭하TP347불수강적연변-피로순배수명상대우순피로조건하도유강저，강저적정도수응변폭적증가이증대。
Research is made on the evolutions of microstructure and fatigue life of TP347H stainless steel under pure fatigue(PF) and creep-fatigue(CF) at 550℃ .The fracture morphology ofscanning electron microscope(SEM) indicates that high temperature dynamic recovery existed under the interactions of creep and fatigue, on the creep-fatigue fracture no secondary cracks and cleavage planes are formed, but on pure fatigue fracture many secondary cracks and small cleavage planes exist; Transmission electron microscope(TEM) morphology indicates that distinct dislocation walls and dislocation cells are formed on local positions under the interactions of creep and fatigue, dislocation multiplication density decreases significantly relative to under pure fatigue. The cyclic softening of TP347H is very obvious and leads to the obvious reduction of fatigue life under interactions of creep and fatigue. Creep-fatigue experiments under various strain amplitude of TP347H prove that creep-fatigue life are reduced obviously relative to pure fatigue, the reduced degree increases with the increment of strain amplitude.