DD6单晶带气膜孔平板试件高周疲劳性能研究

利用电液束、激光、电火花三种不同制孔工艺制备了DD6镍基单晶高温合金气膜孔平板试验件,在980℃下对试件的高周疲劳性能进行了测试,并对疲劳极限与断口形貌进行了分析比较。结果表明:不同制孔工艺对试件的高周疲劳性能影响显著,电液束制孔工艺的疲劳极限较高速电火花制孔、毫秒激光制孔工艺提升约5.3%和7.1%。不同制孔工艺的试样断口形貌特征相似,均属于典型的多源断裂,断面大体分为孔周的裂纹源区、沿{001}面的扩展区及沿{111}面的瞬断区三部分。

Research on High-cycle Fatigue Behavior of DD6 Alloy Plate with Film-cooling Holes

Different drilling processes including electro-hydraulic beam,laser and EDM were used to prepare DD6 nickel-based single crystal superalloy plate with film-cooling holes,the high-cycle fatigue performance of the workpieces were tested at 980℃,and the fatigue limit and fracture morphology were analyzed and compared.The results showed that drilling process has significant effect on the high-cycle fatigue properties of the workpieces,and the fatigue limit of the electro-hydraulic beam drilling process is increased by 5.3%and 7.1%compared with the high-speed EDM and millisecond drilling process.The fracture morphology characteristics of the workpieces by different drilling processes are similar and belonged to typical multi-source fractures.The sections are roughly divided into three parts,including the crack source area around the hole,the expansion area along the{001}plane and the instantaneous fracture area along the{111}plane.