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通过对合金进行不同温度的固溶处理、蠕变曲线测定及组织形貌观察,研究了热处理工艺对4.5%Re镍基单晶合金中温蠕变行为的影响。结果表明:提高合金的固溶温度,可降低合金中元素的偏析程度,提高合金的蠕变性能。完全热处理后单晶镍基合金的组织结构由立方γ’相以共格方式嵌镶在γ基体所组成,在760℃/800 MPa条件下的蠕变期间,合金中γ’相不形成筏状组织,但在近断口区域,立方γ’相的扭曲程度增加。在施加的温度和应力条件下,合金具有良好的蠕变抗力和较长的蠕变寿命。合金在蠕变期间的变形特征是位错在基体中运动和剪切γ’相,其中,切入γ’相的<110>超位错可由{111}面交滑移到{100}面,形成K-W锁,而切过γ’相的<110>超位错在{111}面可发生分解,形成(1/3)<112>超肖可莱不全位错+层错的位错组态,阻碍位错运动和抑制位错的交滑移,是使合金具有良好蠕变抗力的主要原因。
The effect of heat treatment process on the creep behavior of 4.5% Re-Ni single crystal superalloy was investigated by solution treatment, creep curve determination and microstructure observation at different temperatures. The results show that increasing the solution temperature can reduce the degree of element segregation and improve the creep property of the alloy. After the complete heat treatment, the microstructure of the single crystal nickel-base alloy consists of a cubic γ ’phase coherently embedded in the γ matrix. During the creep at 760 ° C / 800 MPa, the γ’ phase in the alloy does not form a raft However, in the near-fracture region, the degree of distortion of the cubic γ ’phase increases. Under the applied temperature and stress conditions, the alloy has good creep resistance and long creep life. The deformation characteristics of the alloy during creep is that the dislocations move and shear the γ ’phase in the matrix. The <110> super-dislocations cut into the γ’ phase can be cross-linked by the {111} plane to the {100} plane to form KW lock, the <110> super-dislocations cut through the γ ’phase can be decomposed on the {111} plane to form a dislocation configuration of (112) <112> Impeding dislocation movement and inhibiting dislocation cross-slip, is to make the alloy has good creep resistance of the main reasons.