【摘要】 通过蠕变曲线测定及组织形貌观察,研究了一种含4.2%Re镍基单晶合金的蠕变行为和组织演化规律。结果表明:单晶合金在试验的温度和应力范围内,对施加应力和温度有明显的敏感性,并测算出合金在稳态蠕变期间的激活能和应力指数。在蠕变初期,合金中γ′相沿垂直于应力轴方向形成N-型筏状结构,蠕变断裂后在远离断口区域形成的筏状γ′相逐渐转变成扭曲形态,在近断口区域的筏状组织转变成与施加应力轴方向呈近45°角度倾斜。合金在稳态蠕变期间的变形机制是位错攀移越过γ′相,位错的攀移通过割阶沿位错线运动而逐步实现;而在蠕变后期,合金的变形机制是位错剪切筏状γ′相。更多还原

【Abstract】 By means of the measurement of creep curves and microstructure observation,an investigation has been made into the creep behaviors and microstructure evolution of a single crystal nickle-based superalloy containing 4.2%Re.Results show that in the range of the applied temperatures and stresses,the superalloy displays an obvious sensibility to the applied temperatures and stresses.During the primary creep,the γ’ phase is transformed into the N-type rafted structure along the direction vertical to the applied stress axis.After crept fracture,the rafted γ’ phase in alloy is gradually transformed into the twisted configuration in the regions far from fracture,up to transformed into the 45° angle arranged,near fracture region,along the direction vertical to the applied stress axis.The dislocation climbing over the γ’ raft phase is thought to be the deformation mechanism of the alloy during the steady creep state,in the later stage of creep,the deformation mechanism of the alloy is dislocation shearing the rafted γ’ phase.更多还原