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通过蠕变性能测试及组织形貌观察,研究了预压缩对一种[001]取向镍基单晶合金蠕变性能的影响。结果表明,[001]取向镍基单晶合金在1040℃/180 MPa条件下沿[100]方向预压缩38 h后,立方??相转化为与[001]取向垂直的P型纤维状筏形组织。合金晶向及预压缩和拉伸蠕变应力轴取向误差是预压缩合金内纤维状??相发生横向连接的原因。合金在预压缩及后续拉伸蠕变过程中??/?相界面能的降低是??相发生组织演化的驱动力。有/无预压缩的[001]取向合金在980℃/200 MPa条件下蠕变至稳态阶段的变形机制为位错在基体通道内的滑移和攀移。相对于未预压缩合金,预压缩后合金的微观组织结构使位错更容易在基体通道中滑移,其对合金沿[001]方向的应变率贡献更大,因此预压缩降低了合金在980℃/200 MPa条件下的蠕变抗力。
The effect of pre-compression on the creep properties of a [001] oriented nickel-base single crystal alloy was investigated by creep test and microstructure observation. The results show that the cubic phase of [001] oriented nickel base single crystal alloy is pre-compressed in the [100] direction at 1040 ℃ / 180 MPa for 38 h, and the cubic phase transforms into a P-shaped fiber raft perpendicular to the [001] orientation organization. Alloy orientation and pre-compression and tensile creep Stress axis orientation error is pre-compression alloy fiber-like phase causes lateral connection. In the pre-compression and subsequent tensile creep process, the reduction of the interfacial energy at the interphase of the alloy is the driving force behind the evolution of microstructure. The deformation mechanism of the [001] oriented alloy creeping to the steady-state phase at 980 ℃ / 200 MPa with and without precompression is the slip and climbing of dislocations in the matrix channel. The microstructure of the pre-compressed alloy allows dislocations to slip more easily in the matrix channel than the uncompressed alloy, which contributes more to the strain rate along the [001] direction of the alloy, so precompression reduces the alloy’s microstructure at 980 Creep resistance at 200C / 200 MPa.