定向凝固镍基高温合金DZ17G的循环蠕变行为  

CYCLIC CREEP BEHAVIOR OF DIRECTIONALLY SOLIDIFIED NICKEL-BASE SUPERALLOY DZ17G

作　　者：袁超[1] 郭建亭[2] 杨洪才[3] 

机构地区：[1]中国科学院金属研究所,沈阳110015 [2]中国科学院金属研究所,沈阳110015 [3]东北大学材料与冶金学院,沈阳110006

出　　处：《金属学报》1999年第9期942-947,共6页Acta Metallurgica Sinica

摘　　要：本文研究了两种方式载荷循环（矩形波和锯齿波）对走向凝固镍基高温合金DZ17G高温蠕变行为的影响结果表明，与恒载荷静态蠕变相比，载荷循环并不影响蠕变塑性，但降低了蠕变寿命，蠕变寿命的降低程度近似与载荷循环次数成正比，且短形波载荷循环比锯齿波载荷循环效果更为明显提出载荷循环导致蠕变寿命的降低与载荷变化引起的滞弹性效应无关，而是蠕变变形加速的结果．在载荷降低时，蠕变阻力的松弛导致在随后加载期间，试样以比相应静态蠕变变形速率更快的速率变形，发生了循环软化，每一次载荷循环产生的循环软化的积累，导致蠕变变形速率不断提高。The cyclic creep behavior of a directionally solidified nickel-base superalloy DZ17G at870℃ under cyclic load in both the square and the sawtooth waveforms with different frequencies has beenexamined. Compared with the constant load creep under a same maximum load, the cyclic load reducesthe fracture life, and the fracture life decreases linearly with increasing cyclic frequency. Moreover, theeffect of reducing fracture life in cyclic load with the square waveform is more than that with the sawtoothwaveform. However, the cyclic load has no effect on the creep ductility. After examining carefully thetransient strain response following the load changing, it is concluded that the anelasticity has no net effecton the creep strain, and the above cyclic creep acceleration is due to the accumulation of an intrinsic creepsoftening during each unloading, which leads to a higher deformation rate on reloading.

关 键 词：定向凝固 镍基 高温合金 循环蠕变 

分 类 号：TG146.15[一般工业技术—材料科学与工程]