GH536高温合金焊接接头疲劳裂纹萌生与扩展原位试验研究  

In-situ Study of Fatigue Crack Initiation and Propagation in Welded Joint of GH536 Superalloy

作　　者：魏振伟[1,2,3] 刘昌奎[1,2,3] 顾玉丽[1,2,3] 陶春虎[1,2,3] WEI Zhen-wei LIU Chang-kui GU Yu-li Tao Chun-hu(AVIC Failure Analysis Center, Beijing Institute of Aerortautical Materials, Bering 100095, China Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Bering 100095, China Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation, Be~iing 100095, China)

机构地区：[1]北京航空材料研究院中国航空工业集团公司失效分析中心,北京100095 [2]航空材料检测与评价北京市重点实验室,北京100095 [3]材料检测与评价航空科技重点实验室,北京100095

出　　处：《失效分析与预防》2016年第6期335-339,共5页Failure Analysis and Prevention

摘　　要：采用原位疲劳试验方法,实时观察了GH536焊接接头疲劳裂纹的萌生和扩展行为,从而揭示了GH536焊接接头疲劳裂纹的萌生和扩展机制:疲劳加载过程中,位错沿滑移带在晶界前沿塞积,晶界阻碍位错运动,裂纹沿滑移带开裂,萌生疲劳裂纹;疲劳裂纹扩展初期,受单滑移的交替作用,裂纹呈"Z"字型向前扩展,随后裂纹的扩展逐渐以主应力控制为主,垂直于加载方向、平直向前扩展;GH536合金焊接接头组织中的晶界和碳化物会阻碍疲劳裂纹的扩展。Behavior of fatigue crack initiation and propagation in GH536 superalloy welded joint was real-timely observed by insitu fatigue experiment. And the mechanism of fatigue crack initiation and propagation was analyzed. During fatigue cycle loading,dislocations move along slip bands and pile up in front of grain boundaries. Grain boundaries hinder the movement of dislocations,eventually causing slip-bands separation and transgranular fatigue crack initiation. At the beginning of crack propagation,crack tip extends in the pattern of ＂Z＂under the alternate effect of single slip systems; and then crack tip extends perpendicularly to the loading direction under the effect of main stress. Grain boundaries and carbides hinder the extending of fatigue cracks.

关 键 词：疲劳 裂纹萌生 裂纹扩展 焊接接头 原位 

分 类 号：TG113[金属学及工艺—物理冶金]