缺口对GH3536镍基高温合金蠕变性能的影响

针对GH3536镍基高温合金无应力集中和带典型应力集中圆棒试样在160,200,240 MPa应力条件下的高温(750℃)蠕变性能进行了试验和有限元分析,研究了缺口的存在对材料蠕变性能的影响。采用扫描电镜分析了试样断口的形貌,确定了材料的断裂机制。结果表明:缺口的存在对GH3536镍基高温合金试件的蠕变性能影响较大,其降低了试件的最大蠕变应变及在蠕变各个阶段的蠕变速率。缺口对试件的蠕变寿命存在硬化作用,缺口根部轴向应力的再分配和松弛可简单认为是导致缺口对该合金蠕变寿命起硬化作用的影响因素。断口形貌分析表明由于缺口的存在,2种试件的表面形貌虽有不同,但蠕变断裂机理都是由微孔洞不断增大与聚集引起的。

Influence of Notch on Creep Properties of GH3536 Nickel-Based Superalloy

High-temperature (750 oC) creep tests of smooth and notched specimens were performed, and the creep properties of GH3536 nickel-base superalloys were investigated under the tension loading of 160 MPa, 200 MPa and 240 MPa. The creep fracture mechanism was revealed with the scanning electron microscopy (SEM) analysis of the fracture surface and finite element analysis (FEM) of the stress distributions. The results show that notches reduce both of the creep deformation and the creep rate compared with the smooth specimen. The FEM analysis indicates that the axial stress redistribution and relaxation in the notch root benefit the creep properties of the specimen and lead to longer creep life. The SEM analysis shows that although the surface morphology is different, the growth and accumulation of microspores are the main factors of creep fracture for both smooth and notched specimens.