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为了深入理解含Re镍基单晶高温合金高温低应力蠕变初期的蠕变行为和强化机制,本文利用电子显微学和能谱学等方法,从介观至原子尺度研究了DD6单晶高温合金在1100℃/140 MPa蠕变15 min后的界面位错组态、界面位错核心结构以及界面位错附近的合金元素分布情况.结果表明蠕变初期合金中的位错密度较低,只在局部形成位错网络,因此蠕变初期γ此蠕变界面形成的V形和台阶状凸起结构数量明显低于稳态蠕变初期(12h)时的,而且台阶状凸起结构(对应a/2<101>60°混合型位错)明显多于V形凸起结构(对应a/2<110>刃型位错,由位错反应形成).蠕变初期形成的特殊形状的台阶状凸起结构是由于界面位错沿γ/γ′界面运动形成的,而Re等合金元素的共偏聚进一步验证了Re元素偏聚同界面位错的交互作用.
In order to understand deeply the creep behavior and strengthening mechanism at the early stage of high-temperature and low-stress creep of Re-containing Ni-base single crystal superalloy, electron microscopy and energy dispersive spectroscopy were used to study the effect of DD6 single crystal high temperature The interface dislocation configuration, the interface dislocation structure and the distribution of alloying elements in the vicinity of interface dislocations after creep at 1100 ℃ / 140 MPa for 15 min show that the dislocation density is low in the early stage of creep In the early stage of creep, the number of V-shaped and step-like convex structures formed at γ creep interface is obviously lower than that at the initial stage of steady-state creep (12h), and the step-like convex structure (corresponding to a / 2 <101> 60 ° mixed dislocations) is significantly more than the V-shaped convex structure (corresponding to the a / 2 <110> edge dislocations, formed by the dislocation reaction). The special shape of the step-shaped The convex structure is formed by the movement of interfacial dislocations along the γ / γ ’interface. The co-segregation of alloying elements such as Re further verifies the interaction of Re-element segregation with interfacial dislocations.