摘要
镍基单晶高温合金是一种极为重要的高温结构材料,主要用于制造航空发动机叶片等热端部件。位错是引起材料塑性变形的主要原因,会导致零件失效或断裂。镍基单晶高温合金在实际服役过程中形成的位错类型多样、形态各异,对蠕变性能的影响也各不相同。因此,位错与蠕变机制的关系一直是高温合金性能研究的重点,备受国内外学者关注。单晶高温合金中的位错组态主要包括γ相中的独立位错、形成堆垛层错的位错、界面位错网以及γ′相中的超位错。独立位错、堆垛层错、界面位错网和γ′相中各种类型的超位错均是位错与溶质原子、位错与γ′相以及位错与位错之间复杂交互作用的结果。基体通道中的独立位错形成于蠕变初期,是所有位错之源。堆垛层错是高温合金低温蠕变中最常见的位错组态,既可存在于基体相,也可存在于γ′相,层错形貌与两相层错能大小有关。界面位错网呈四方状或六方状,集中分布于γ/γ′两相界面附近,是高温蠕变的典型组织特征之一。高温蠕变下进入γ′相的超位错有两种,分别是〈110〉型超位错和〈010〉型超位错,两种超位错通过γ′相的机制明显不同,〈110〉型超位错主要以切割方式穿过γ′相,而〈010〉型超位错只能以滑移和攀移相结合的方式通过γ′相。合金的蠕变性能与位错组态密切相关。堆垛层错是合金层错能低的表现,低层错能会增大初始蠕变量,缩短合金的低温蠕变寿命;界面位错网是位错与两相错配应力交互作用的结果,位错网阻碍了位错切割γ′相,对高温蠕变性能非常有利;位错穿过γ′相是高温合金高温蠕变的控制性因素,进入γ′相的超位错因类型不同,对蠕变性能的影响也明显不同。对高温合金中各种位错形貌、结构以及形成过程的认识是高温合金蠕变机理研究的基础,关于位错组态对蠕变性
Nickel-based single crystal superalloy is an extremely important high-temperature structural material, mainly used to manufacture the hot end components such as aero-engine blades. Dislocations are the main reason for plasticdeformation of materials and can directly lead parts to failure or fracture. The dislocations in nickel-based single crystal superalloys formed in actual service processes, come in many types and morphologies and have different effects on creep performance. Therefore, the research on the relationship between dislocation and creep mechanism has been the focus of superalloys performance research, and has attracted the attention of researchers at home and abroad. The single crystal sueralloys consists of γ matrix and γ′ precipitate. The dislocations in Ni-based single crystal superalloys mainly include: independent dislocations in γ matrix, stacking fault, dislocation network, and super dislocations in γ′ precipitate, which are the result of interactions between dislocations and solute atoms, dislocations and γ′ precipitate, and dislocations and dislocations. Independent dislocations are formed in matrix channel at primary creep and are the source of all dislocations such as dislocation network and super dislocations. Stacking fault is the most common dislocation configuration in low temperature creep of superalloys. It can exist alone in the γ matrix phase, as well as in the γ′ phase. The stacking fault morphology is related to the fault energy of γ and γ′ phase. The interface dislocation network is mainly tetragonal or hexagonal, and is concentrated in the vicinity of the γ/γ′ two phase interface, which is one of the typical structural features of high temperature creep. There are two kinds of super dislocations entering γ′ precipitate under high temperature creep, which are 〈110〉 type super dislocation and 〈010〉 type super dislocation. The mechanisms of the two super dislocations through γ′ phase are obviously different.〈110〉 type super dislocations ma
作者
何闯
刘林
黄太文
杨文超
张军
傅恒志
HE Chuang;LIU Lin;HUANG Taiwen;YANG Wenchao;ZHANG Jun;FU Hengzhi(State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi an 710072)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2019年第17期2918-2928,共11页
Materials Reports
基金
国家自然科学基金项目(51631008
51690163
51690160
51501152
51771148)
国家重点基础研究发展计划项目(2016YFB0701400
2017YFB0702902)~~
关键词
镍基单晶高温合金
位错形成机制
合金强化
蠕变性能
Ni-based single crystal superalloys
dislocations formation mechanism
alloy strengthening
creep behaviors
