中文摘要：

对第二代DD6单晶高温合金进行了标准热处理和热等静压处理＋标准热处理,然后再在850℃和300-850 MPa应力条件下进行高温高周疲劳试验,观察了不同处理状态合金的显微组织,分析了热等静压处理对合金显微组织和高温高周疲劳性能的影响。结果表明：与仅进行标准热处理的合金相比,增加热等静压处理后,合金内部显微疏松的数量和尺寸显著降低,其体积分数从0.31%降低到0.04%,合金的高周疲劳强度由331MPa提高至433MPa,高周疲劳寿命也显著提高。

英文摘要：

Standard heat treatment and hot isostatic pressing（HIP） followed by standard heat treatment were conducted on a second generation single crystalsuperalloy DD6, and then high-temperature high cycle fatigue （HCF） test were carried out under the conditions of 850℃ and stress between 300 MPa and 850 MPa. The microstructure of the alloy in different states was observed, and the effects of HIP on microstructure and HCF properties of the alloy were investigated. The results show that, compared with the alloy only treated with standard heat treatment, the number and size of porosity in the alloy treated by HIP decreased obviously, the volume fraction of porosity deceased from 0.31% to 0.04%; its high cycle fatigue strengths increased from 331 MPa to 433 MPa, and its high cycle fatigue life raised sharply.