元素Ru对镍基单晶合金的组织与蠕变性能的影响

发布时间：2018-11-18 21:40

【摘要】：本文通过设计和制备出有/无Ru镍基单晶合金,对合金进行不同工艺热处理、蠕变性能测试和组织形貌观察,研究了元素Ru和热处理工艺对镍基单晶合金组织与蠕变性能的影响,并采用热力学方法进行不同温度的层错能计算,讨论了温度对合金层错能及变形机制的影响。结果表明,无Ru镍基单晶合金在蠕变期间析出大量针状TCP相,是具有较低蠕变性能的主要原因,加入元素Ru可抑制合金中析出TCP相,并大幅度提高镍基单晶合金的蠕变寿命。4%Ru镍基单晶合金经1050℃?3h A.C时效及完全处理可使合金获得较好的组织与蠕变性能,其中,测定出合金在760℃/780MPa、980℃/200MPa和1100℃/120MPa的蠕变寿命分别为423h、333h和232h。在低于850℃蠕变期间,合金中??相仍保持立方形态,其变形机制是位错在?基体相中滑移和剪切进入??相,且剪切进入??相的位错可发生分解,形成不全位错加层错的位错组态。在高于980℃蠕变期间,合金中??相已沿垂直于应力轴方向转变成筏状结构,稳态蠕变期间的变形机制是位错在基体中滑移和攀移越过筏状??相,蠕变后期的变形机制是位错在基体中滑移和剪切进入筏状??相,且剪切进入筏状??相的位错不发生分解。温度对合金层错能的影响是致使合金在不同温度有不同变形机制的主要原因。合金在低于850℃时有较低的层错能,剪切进入??相的位错可发生分解,形成不全位错加层错的位错组态;随蠕变温度提高,合金的层错能增大,是致使合金在高温蠕变期间剪切进入??相的位错不发生分解的主要原因。蠕变后期,合金中主/次滑移系中位错的交替开动,可使??相发生粗化和扭曲,并在垂直于应力轴的??/?两相界面发生裂纹的萌生和扩展,直至发生断裂,是镍基单晶合金在高温蠕变期间的损伤和断裂机制。
[Abstract]:In this paper, a single crystal alloy with or without Ru was designed and prepared. The alloy was subjected to different heat treatment, creep property test and microstructure observation. The effect of element Ru and heat treatment on microstructure and creep properties of Ni-base single crystal alloy was studied. The stacking fault energy at different temperatures was calculated by thermodynamic method. The effect of temperature on stacking fault energy and deformation mechanism was discussed. The results show that a large number of needle-like TCP phases are precipitated during creep, which is the main reason for the low creep properties of Nickel-base alloy without Ru. The addition of the element Ru can inhibit the precipitation of TCP phase in the alloy. The creep life of nickel base single crystal alloy was greatly improved. The microstructure and creep properties of 4%Ru nickel base single crystal alloy were obtained by aging and complete treatment at 1050 鈩，

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