摘要
对316L不锈钢进行873 K圆路径不同应变范围的低周疲劳实验,分析其动态应变时效(DSA)的循环周次、应变范围和受载状态相关性。实验发现,循环初期DSA现象明显,随后逐渐减弱,大应变幅值下失效前产生了大量Snoek溶质原子气团,使得该阶段DSA现象再次显著。从应变范围相关性分析中可以看出,应力跌幅和锯齿密集程度随着应变范围的增加而增大,位错增殖造成了大应变范围下锯齿数量的增多。热力学分析表明,当压缩向卸载阶段转变时,静水压力方向使空位的扩散性得到抑制,压缩阶段锯齿屈服现象更为明显。扫描电镜结果显示,0.7%和1.0%两等效应变范围下材料的失效是疲劳、动态应变时效和氧化共同作用的结果。
Low cycle fatigue tests in different strain ranges were conducted for 316 L stainless steel at873 K under circular loading. The effects of number of cycles,strain range,and loaded state on the dynamic strain aging（ DSA） are discussed. DSA is more obvious in the initial several cycles,followed by weak serrated yielding. The DSA is evident before failure in larger strain range,which can be attributed to the formation of the Snoek solute atom atmospheres. The results of the effect of strain range on DSA show that the stress drop value and the serrated yielding degree increase with the increase in strain range.The increase in serrated number in larger strain range is due to the dislocation multiplication. The thermomechanical analysis shows that the serrated yielding phenomenon is more significant due to the hold-up of vacancy diffusivity when the compression changes to unloading. Scanning electron microscope（ SEM）results show that the material failures are attributed to fatigue,DSA,and oxidation in two strain ranges.
作者
金丹
张江玉
李江华
JIN Dan;ZHANG Jiang-yu;LI Jiang-hua(School of Energy and Power Engineering, Shenyang University of Chemical Technology, Shenyang 110142, Liaoning, China)
出处
《兵工学报》
EI
CAS
CSCD
北大核心
2018年第3期584-589,共6页
Acta Armamentarii
基金
国家自然科学基金项目(11102119)
辽宁省自然科学基金项目(201602586)
关键词
316L不锈钢
动态应变时效
圆路径
应力跌幅
位错
316L stainless steel
dynamic strain aging
circular loading
stress drop
dislocation
