基于位错运动的镍基单晶各向异性蠕变寿命预测  

Anisotropic Creep Life Prediction of Nickel-based Single Crystal Based on Dislocation Movement

作　　者：张诚江 胡卫兵[1] 王佳坡 童文伟 温志勋[2] 岳珠峰[2] Zhang Chengjiang;Hu Weibing;Wang Jiapo;Tong Wenwei;Wen Zhixun;Yue Zhufeng(Xi’an University of Architecture and Technology,Xi’an 710055,China;Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西安建筑科技大学,陕西西安710055 [2]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2019年第12期3930-3938,共9页Rare Metal Materials and Engineering

基　　金：国家自然科学基金（51875461,51875462）;陕西省自然科学基础研究计划-重点项目（2018JZ5002）;陕西省创新能力支撑计划（2018KJXX-007）

摘　　要：对3种不同取向的DD6镍基单晶高温合金进行了980℃下的蠕变试验,结果表明镍基单晶高温合金蠕变失效机理是材料内部微孔洞的萌生与微裂纹的扩展,其本质是由位错运动造成的。采用透射电镜(TEM)对蠕变初期[001]、[111]和[011]3种取向的单晶合金的位错形貌进行观测,发现其分别符合八面体滑移系开动、六面体滑移系开动与两滑移系同时开动的特征。针对上述微观现象,基于晶体塑性理论建立了考虑Orowan效应与位错阻碍效应的蠕变本构模型与蠕变损伤模型,并根据试验得到的蠕变曲线拟合了模型参数。该模型的有限元模拟结果与单晶材料的蠕变断口形貌相互印证,解释了单晶蠕变的各向异性的力学行为。The creep tests of three different orientations of the single crystal superalloy DD6 were carried out at 980 °C. The results indicate that the creep failure mechanism of superalloy is the initiation of micropores and the propagation of microcracks, which is caused by dislocation motion. The dislocation morphology of monocrystals in [001], [111] and [011] orientation at the initial stage of creep was analyzed by transmission electron microscopy(TEM), matching the characteristics of the octahedral sliding system activated, the hexahedral sliding system activated and the simultaneous motion of the two sliding systems, respectively. Based on the crystal plasticity theory, the creep constitutive model and creep damage model under variational stress conditions considering Orowan effect and dislocation blocking effect were established;meanwhile, the model parameters were fitted according to the creep curve obtained from the test. Moreover, the finite element simulation results of the model and creep fracture morphology of monocrystalline materials confirm each other and explain the anisotropic behavior of monocrystalline creep.

关 键 词：镍基单晶高温合金 位错运动 蠕变断口 晶体塑性 

分 类 号：TG146.1^+5[一般工业技术—材料科学与工程]