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通过蠕变性能测试及组织形貌观察,研究了横向预压缩对[011]取向镍基单晶高温合金在1040℃,137 MPa条件下拉伸蠕变行为的影响.结果表明,[011]取向镍基单晶高温合金在1040℃,180 MPa条件下沿[100]方向预压缩38 h后形成了总体上平行于压应力轴方向的P型g’筏状组织.预压缩期间不同晶面不同的应变能密度分布及晶格应变是g’相筏形化的主要原因.位错在基体通道中的滑移是有/无预压缩[011]取向合金在稳态蠕变阶段主要的变形机制,其中在预压缩合金内存在较多的位错攀移运动.横向预压缩显著提高了[011]取向合金在1040℃,137 MPa条件下的蠕变抗力.合金内的“山墙型”基体通道的消除、稳态蠕变阶段较小的g基体宽度、筏状组织横向连接形成的微观瓶颈状g基体通道和“迷宫式”的组织以及较多数量滑移系的开动,均有助于通过限制位错的运动,提高预压缩合金的蠕变抗力.
The effect of transverse pre-compression on the tensile creep behavior of [011] -oriented nickel base single crystal superalloys at 1040 ℃ and 137 MPa was studied by means of creep test and microstructure observation. The results show that [011] orientation Ni-based single crystal superalloy was pre-compressed in the [100] direction at 1040 ℃ and 180 MPa for 38 h to form P-type g-raft structure generally parallel to the direction of compressive stress axis. The distribution of strain energy density and lattice strain are the main reasons for the raft of g ’phase.The slip of dislocations in the channel of the matrix is the primary deformation mechanism of [011] oriented alloy during steady creep phase , Where there is more dislocation climbing movement in the pre-compression alloy.The transverse pre-compression significantly enhances the creep resistance of the [011] oriented alloy at 1040 ℃ and 137 MPa.The “gable type” The elimination of matrix channels, the smaller g matrix width in the steady-state creep phase, the microscopic bottle-neck g-matrix channels and the “labyrinthine” organization formed by the transverse connection of the raft and the initiation of a larger number of slip systems Helps to improve creep resistance of pre-compressed alloys by limiting movement of dislocations.