研究了一种[110]取向的镍基单晶高温合金在1 040 ℃、150 MPa和850 ℃、500 MPa条件下的蠕变性能、蠕变过程中γ′相的形貌演变以及γ′相的筏化机理,并对拉断后试样的纵向截面进行了SEM形貌观察.结果表明:在1 040 ℃、150 MPa条件下,沿[110]取向施加应力拉伸时,合金中γ′相形成了与应力轴成45°角的层片状筏化组织;距断口不同位置处γ′相的粗化程度存在明显差异;而在850 ℃、500 MPa条件下,拉伸蠕变后合金中γ′相没有发生明显的粗化现象.

The tensile creep tests were conducted on a Ni-base single crystal superalloy with [110] orientation under the conditions of 1 040 ℃/150 MPa and 850 ℃/500 MPa,respectively.The creep properties and the microstructure evolution during the creep process were investigated.The longitudinal section morphology of the tensile fracture was observed by SEM.The results show that the γ′ phase of the Ni-base single crystal superalloy with [110] orientation formed the lamellar-type raft structure with inclined 45° with the stress axis under the condition of 1 040 ℃/150 MPa.There was evident difference in the degree of γ′ phase coarsening at different distances away from the fractured surface.However,the γ′ phase was not coarsened obviously under the condition of 850 ℃/500 MPa.