带V型缺口圆棒试样三轴应力状态下的蠕变性能

Creep Properties of V-notched Round Rod Specimen under Triaxial Stress State

研究了750℃、应力水平为200、240 MPa条件下带V型缺口和光滑表面的GH3536圆棒试件的蠕变性能。通过扫描显微镜从微观角度分析了缺口对蠕变断裂的影响机理。采用修改的K-R模型,研究了缺口应力和损害蠕变时间的变化。结果表明：V型缺口提高了蠕变实验的强度,随着应力的增加,其强化效应增强。V型缺口圆棒试样的蠕变损伤和局部失效全都出现在缺口根部相对较浅的位置。

The creep properties of GH3536 round bar specimens with V-notched and smooth surface were studied under the condition of 750 ℃ and stress level of 200 MPa and 240 MPa. The effect mechanism of the notch on the creep rupture was analyzed from the microscopic perspectives by SEM. The modified K-R theory was used to study the change in notch stress and damage creep time. The results show that the V-notch improves the strength of the creep test and its strengthening effect increases with stress increasing. The creep damage and partial failure of the V-notch round bar specimens all appear at relatively shallow position at the root of the notch.