【摘要】 通过测定一种单晶镍基合金的高温拉伸蠕变曲线及位错运动的内摩擦应力σ0,建立了综合蠕变方程,计算出稳态蠕变期间的表观蠕变激活能及相关参数.结果表明:在蠕变期间,位错运动的内摩擦应力σ0,随外加应力的提高略有提高,随温度的升高而明显降低。蠕变后期,由于缩径使样品不同位置承受不同的有效的应力,导致筏状γ′相具有不同的粗化特征,在近断口处,载荷的有效应力增大,使筏状γ′相扭曲且粗化加剧。界面位错网对形变硬化和回复软化具有协调作用,并减缓位错切入γ′相,因此有利于合金蠕变抗力的提高.更多还原

【Abstract】 The creep equation have been set up,and the creep activation energy and stress exponent have been calculated by means of measurement of the creep curves and internal fractional stresses of dislocation motion during creep of a single crystal nickel-base superalloy.Results show that the values of the internal fractional stress（σ₀） are enhanced with the increase of applied stress,and reduced with the increase of temperature.The various coarsening features are displayed at different regions of the tensile sample due to the difference of the stress field.The γ′ rafted phase near the fracture displays an obvious twisted and coarsened feature.The dislocation networks on the γ/γ′ phase interfaces could accommodate and slow down the process of dislocation shearing γ′ phase which is for the strain strengthening and recover softening during creep,therefore,in favor of improving the creep resistance of superalloys.更多还原