单晶高温合金的冷热疲劳裂纹生长行为研究  

Thermal Fatigue Behavior of Single-Crystal Superalloy

作　　者：刘源[1,2] 于金江[1] 徐岩[1] 孙晓峰[1] 

机构地区：[1]中国科学院金属研究所,辽宁沈阳110016 [2]中国科学院研究生院,北京100039

出　　处：《稀有金属材料与工程》2009年第1期59-63,共5页Rare Metal Materials and Engineering

摘　　要：研究了3种不同镍基高温合金在不同的热循环温度下的热疲劳性能。结果表明,单晶高温合金具有较好的热疲劳抗性。分别用光学显微镜和扫描电镜对热疲劳裂纹的萌生和扩展行为进行观察发现,裂纹首先在缺口处萌生,而在不同合金中裂纹的扩展行为具有显著差异。在单晶高温合金中裂纹的扩展方向与枝晶生长方向成45o,而在Mar-M002多晶定向合金中,裂纹则主要沿着枝晶间区域的共晶和碳化物进行扩展。扩展方式的不同对合金的热疲劳抗性会产生很大的影响。The effects of cycle temperatures on the thermal fatigue crack growth of three kinds of superalloys were investigated. The experimental results show that the crack growth rate increases with the rise of cycle temperature. Optical Microscopy （OM） and Scanning electron microscopy （SEM） observations reveal that multiple small cracks primarily initiated at the notch tip in any temperature range. Subsequently, only one or two small cracks can continue to grow, and finally form the main cracks. The crack growth behavior varies distinctly for different alloys. In general, thermal fatigue cracks propagate along a preferential direction with the dendrite growth direction in single crystal superalloy, but along the interdendritic region for the Mar-M002 alloy.

关 键 词：单晶高温合金 热疲劳 裂纹萌生和扩展 

分 类 号：TG132.32[一般工业技术—材料科学与工程]