气膜孔分布对DD6单晶高温合金持久性能及断裂行为的影响  

Influence of Cooling Holes Distribution on Stress Rupture Property and Fracture Behavior of Single Crystal Superalloy DD6

作　　者：胡春燕[1,2] 刘新灵[1,2] 陶春虎[1,2] 曹春晓[1,2] 

机构地区：[1]北京航空材料研究院,北京100095 [2]航空材料检测与评价北京市重点实验室,北京100095

出　　处：《材料工程》2016年第5期93-100,共8页Journal of Materials Engineering

基　　金：航空科学基金(KZ43150734);中航工业航材院创新基金(KJSJ140739)

摘　　要：研究在980℃/300MPa条件下不同气膜孔分布对DD6单晶气冷叶片模拟试样持久性能及断裂行为的影响。结果表明:在相同的温度和应力条件下,气膜孔的分布是影响模拟试样持久寿命的主要因素;随着气膜孔排数的增加,持久寿命呈规律性下降,而带1排孔、2排孔试样的持久寿命与不带孔的持久寿命略长。通过断口微观和金相组织观察发现,不带孔试样的断裂方式为微孔聚集型断裂,断口上分布着大量方形小平面特征,断口附近纵剖面上可见明显的心部裂纹;而带气膜孔试样的持久变形主要出现在气膜孔区域,断口整体氧化较严重,方形小平面特征减少,韧窝特征明显增加,断口附近纵剖面上气膜孔处均可见裂纹及氧化形貌。基于晶体塑性理论分析了不同孔分布下孔边应力的分布规律,模拟结果显示在气膜孔周边存在应力集中和应力重分布,数值模拟分析结果与试样的断裂位置及形貌吻合。The influence of different cooling holes distribution on stress rupture property and fracture behavior of air-cooled turbine blades modeling specimens of single crystal superalloy DD6 at 980℃/ 300MPa was analyzed. The results show that cooling holes distribution is the main factor affecting the stress rupture life at the same temperature and stress conditions. The stress rupture life of modeling specimens declines regularly as rows of cooling holes increase, however, the stress rupture life of modeling specimens with one row cooling holes or two rows cooling holes is slightly longer than that without cooling holes. Based on fracture surface and metallurgical observations, the specimens with- out cooling holes fracture in the mode of microvoid coalescence. The fracture surface is made up of small square-shaped facets and there are heart checks near the fracture surfaces of the specimens, but for the specimens with cooling holes, the fracture cracks initiate from the cooling holes and stress rup- ture deformation concentrates on the region near cooling holes. The whole fracture surface oxidizes se- riously and the small square shaped facets reduce, dimples increase. In addition, there are cracks and oxidization characteristics near the fracture surfaces of the specimens. Based on the crystal plasticity theory, the distribution of stress along cooling holes is obtained. The simulated results show that stress concentration and redistribution occur around the cooling holes, and the form of the fracture surface is consistent with numerical analysis.

关 键 词：DD6单晶高温合金 气冷叶片 气膜孔 持久性能 断裂行为 

分 类 号：TG132.3[一般工业技术—材料科学与工程]