利用螺旋选晶法制备了不同钽含量的低成本镍基单晶高温合金, 研究了在850 ℃, 441 MPa及950 ℃, 250 MPa条件下钽对合金的蠕变性能及蠕变机制的影响。结果表明: 钽含量越多, 合金中γ/γ′晶界处的位错网越完整, 合金的蠕变寿命越长; 随着钽含量的提高, 850 ℃, 441 MPa时合金的蠕变机制由位错的滑移以及切割γ′向层错方式转变; 950 ℃, 250 MPa时合金的蠕变机制由位错以层错方式切割γ′向攀移转变。

Ni-based superalloys with different Ta contents were prepared by using screw selecting method. The effects of Ta on creep property and creep mechanism of the alloys at conditions of 850 ℃, 441 MPa and 950 ℃, 250 MPa were investigated. Results show that with the increasing of Ta content, the dislocation net at γ/γ′ interface facilitated and the creep rupture life of the alloys increased. When Ta content rose, the creep mechanism of the alloy transformed from dislocations sliding and cutting to stacking faults at 850 ℃, 441 MPa, and transformed from stacking faults to climbing of the dislocations at 950 ℃, 250 MPa.