摘要
研究了同成分合金在定向凝固（ＤＳ）和普通铸造（ＣＣ）状态下７６０℃的低周疲劳性能。结果表明，ＤＳ合金的疲劳寿命比ＣＣ合金在应力控制条件下高２倍左右，而在应变控制条件下可提高寿命２０倍左右。ＣＣ合金的疲劳裂纹往往萌生在与表面相连的晶界或某些缺陷（如孔洞）上，由外向内沿晶界扩展。而ＤＳ合金裂纹则起源于纵向晶界的横段或预开裂的碳化物，并沿枝晶间穿枝干扩展。
The low cycle fatigue(LCF)properties of a directionally solidified(DS)superalloy have been studiedat 760℃ and compared with that of the conventional cast(CC)superalloy with same composition as the DSalloy, It was showed that the fatigue life of DS alloy is twice higher than that of CC alloy under stress-con-trol condition,and about 20 times higher than CC alloy under strain-control condition,The fatigue cracksin CC alloyinitiate in some defects,such as the porosities or the grain boundary conjucting to specimen sur-face,and growth inwards along the grain boundary,but in the DS alloy the fatigue cracks initiate at thetransverse segment of longituthnal grain boundary or some pre-cracking carbides,and growth along thedendritic zone and cross the dendrites.
出处
《航空材料学报》
CAS
CSCD
1994年第3期27-34,共8页
Journal of Aeronautical Materials
关键词
定向凝固
低周疲劳
微观组织
耐热合金
directionally solidification,superalloy,low cycle fatigue,microstructure
