材料期刊网

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。

By means of the solution treatment,creep curves measurement and microstructure observation,the influence of solution temperatures on creep behaviors of 4.5%Re single crystal nickel-base superalloy during medium temperature was investigated.Results show that the creep properties of the alloy enhances with solution temperature due to decreasing the segregation extent of the elements.After fully heat treated,microstructure of the alloy consists of the cubic γ′ phase embedded coherent in the γ matrix.In the ranges of the applied stresses and temperatures,the alloy displays the longer creep lifetime.During creep at 760 ℃/800 MPa,no rafted microstructure of the γ′ phase is detected,but the configuration of the γ′ phase in the regions near the fracture is twisted.The deformation features of the alloy during creep are that the dislocations move in the γ matrix channels and shear into the γ′ phase,the 〈110〉 super-dislocation shearing into the γ′ phase can slip from {111} planes to {100} planes to form K-W locking,or the 〈110〉 super-dislocation shearing into the γ′ phase is decomposed to form the configuration of(1/3)〈112〉 super-Shockleys partials plus the stacking fault,which may hinder dislocations movement and restrain the cross-slipping of dislocations.This is thought to be the main reason of the alloy having a better creep resistance.