Development of two rhenium- containing superalloys for single- crystal blade and directionally solidified vane applications in advanced turbine engines

A team approach involving several turbine engine companies using the concepts of simultaneous engi-neering has been used to successfully develop CMSX-4 ® alloy for turbine blade applications. CMSX-4 al-loy is a second-generation, single-crystal cast nickel-base superalloy containing 3% Re and approximately 70% volume fraction of γ. The high level of balanced properties determined by labora-tory evaluation has been confirmed during field testing of the Solarγ Mars T-14000 industrial gas turbine with CMSX-4 single-crystal (SX) blades in both the coated and bare condition. A similar collaborative ap-proach has resulted in the successful development of CM 186 LCγ alloy for complex, directionally solidi-fied (DS) columnar grain vane segments. CM 186 LC alloy is a second-generation DS columnar grain cast nickel-base superalloy containing 3% Re and approximately 65% volume fraction of γ. Excellent com-ponent producibility and quality is demonstrated. Turbine engine testing is scheduled to commence by the end of 1993.     

基于知识模板的涡轮叶片精铸模设计方法研究

提出了基于知识模板的涡轮叶片精铸模设计方法,介绍了知识模板的定义、构建方法及基于知识模板的设计方法等关键技术。面向装配过程,设计了具有参数化关联的模具模板结构,实现基于模板知识的精铸模自动生成,缩短了精铸模设计周期,提高了精铸模标准化程度和设计知识利用率。     

单晶高温合金的中温Ⅰ阶蠕变--涡轮叶片伸长的重要因素

单晶镍基高温合金已广泛用于制造先进燃气涡轮叶片,但这种合金至今仍被忽视的薄弱环节是它的中温Ⅰ阶蠕变伸长量远高于高温蠕变,而且与高温蠕变相比,中温Ⅰ阶蠕变对取向偏离、合金成分和热处理组织的变化更为敏感.虽然预蠕变引进较高的位错密度能有效抑制中温蠕变,但在实用上仍有困难.在选用单晶合金作为涡轮叶片时,应考虑到先进的二代和三代单晶在中温下的抗变形能力不如一代单晶,同时中温大应力状态下的叶片根部可能过度伸长.     

熔融沉积式燃机叶片快速熔模铸造技术研究与试验

针对某燃机叶片叶型部分形状复杂和轮廓度精度要求高的特点,提出了一种基于熔融沉积技术的燃机叶片快速熔模铸造方法,通过基于NURBS曲线的分层截面生成算法对燃机叶片STL(stereolithography)模型进行分层,提高燃机叶片模样的轮廓度精度,制订了燃机叶片快速熔模铸造工艺流程,采用三坐标测量机对燃机叶片铸件进行测量,对其两个关键截面进行型线轮廓度偏差分析与评价,结果表明:基于熔融沉积技术的快速熔模铸造燃机叶片铸件在轮廓精度方面满足要求,快速熔模铸造工艺流程合理、可行。     

Influence of service-induced microstructural changes on the aging kinetics of rejuvenated Ni-based superalloy gas turbine blades

Rejuvenation of Ni-based superalloy gas turbine blades is widely and successfully employed in order to restore the material microstructure and properties after service at high temperature and stresses. Application of hot isostatic pressing (HIP) and re-heat treatment can restore even a severely overaged blade microstructure to practically “as-new” condition. However, certain service-induced microstructural changes might affect an alloy’s behavior after the rejuvenated blades are returned to service. It was found that advanced service-induced decomposition of primary MC carbides, and the consequent changes of the γ-matrix chemical composition during the rejuvenation, can cause a considerable acceleration of the aging process in the next service cycle. The paper will discuss the influence of the previous microstructural deterioration on the aging kinetics of rejuvenated gas turbine blades made from IN-738 and conventionally cast GTD-111 alloys.     

An integration system for investment casting mould design of aeroengine turbine blade

An integration system was developed to satisfy the need of information integration in the process of designing, investment casting and monitoring aero-engine＇s turbo blade. The general architecture is detailed presented in this paper. The system mainly comprises of product master model, design information management, anti-deformation design of mould cavity, intelligence mould design and blade testing. The developed system can manage mould design and blade test data flow, optimize mould design process and achieve the goal of integration design.     

离心铸造自生Zn—Al—Si表面复合材料的组织与性能

采用热膜金属型离心铸造Zn-27Al-5Si合金,获得了内层含大量初晶Si,外层有少量初晶Si,中层为细小共晶Si的表面复合材料,考察了复合材料的组织形貌和复合材料的,吧及模温和转速对组织的影响。结果,随着模温的提高,初晶Si、共晶Si和基体组织变得粗大;随着模转速的增加,初晶Si在内侧富集层厚度减小,初晶Si面积比增大。复合材料的内层由于聚集了大量初晶Si而具有较高的硬度和较优的耐磨性。复合材料的断裂方式为脆性断裂,含共晶Si的中层在断裂中比含块状初晶Si的内层经历了更多的塑性变形。     

热处理对原位自生Mg2Si/Mg-Al基复合材料组织与性能的影响

利用金属型铸造制备了原位自生Mg2Si/Mg-Al基复合材料,研究了热处理对该材料组织与性能的影响。结果表明T4处理改变了Mg2Si/Mg-Al基复合材料中Mg2Si的形貌与分布。随着保温时间的延长,棱状枝晶Mg2Si相发生熔断、球化,最终成为尺寸为10-30μm的颗粒;同时β-Mg17Al12相溶入到α-Mg基体中,在随后的时效过程中发生沉淀析出。由于β-Mg17Al12相的溶解,T4处理会降低该材料的硬度,但随后的时效析出可提高其硬度,415℃×12h固溶处理后175℃×16h(T6)时效,硬度可提高14.9%。热处理过程中棱状枝晶Mg2Si相的粒化可用吉布斯-汤姆逊定理解释。     

Friction and wear properties of casting in-situ silicon particle reinforced ZA27 composites

The effects of silicon particle content and testing temperature on friction and wear properties of casting in-situ silicon particle reinforced ZA27 composites were investigated. The wear mechanisms were mainly discussed by observations of both worn surfaces and their side views. The results indicated that the variations of wear resistance with increasing of silicon particle content, at all of the testing temperatures applied, showed a similar tendency with a manner of non-monotonous change. It was surpdsed that the wear resistance decreased with the increase of silicon particle content from 2 vol.% to 5 vol.%, while it increased when the content was less than 2 vol.% or more than 5 vol.%. Similarly, the friction coefficient also did not change monotonously. The dominative wear mechanism changed from a relatively severe regime of plastic deformation accompanied by adhesion wear to a mild regime of smear, then to a very severe regime of severe plastic deformation induced wear, and finally again to a relatively mild regime of smear accompanied by abrasive wear as the silicon content increased. The wear resistance always decreased with elevating testing temperature, but the decrease ranges were different for the composites with different silicon contents. The friction coefficients changed irregularly for the different composites with the increase of testing temperature. Correspondingly, the wear mechanism alternated from a mild regime of smear accompanied by abrasive wear to a severe regime of plastic deformation accompanied by adhesion wear.     

Influences of processing parameters on microstructure during investment casting of nickel-base single crystal superalloy DD3

The effects of solidification variables on the as-cast microstructures of nickel-base single crystal superalloy DD3 have been investigated by using the modified Bridgman apparatus.The experiments were ...     

Geometric analysis of investment casting turbine blades based on digital measurement data简

A turbine blade is one of the key components of the aero-engine.Its geometric shape should be inspected carefully in the production stage to ensure that it meets the tolerance specification.In the present paper,an approach for investment turbine blade geometric shape analysis based on multi-source digital measurement is presented.Its key technologies,such as measurement data collection,blade model reliable alignment,geometric shape deviation fast calculation and visualization,were investigated.Actual measurement data from a structure light measurement device and a Coordinate Measuring Machine （CMM） for turbine blades were used to validate the presented method.The experimental results show that the proposed method is accurate,quick and effective to implement.     

微合金化对Cu-15Cr原位复合材料组织和性能的影响

研究了合金元素Zr对Cu-15Cr原位复合材料微观组织、力学性能、导电性能及热稳定性的影响规律。用SEM和TEM分别观察了材料的微观组织演变和析出相形貌,测试了不同应变下材料的抗拉强度和导电率,测定了材料的抗软化温度。结果表明:Zr促进Cr的析出,保持了微合金化Cu-15Cr复合材料的导电性;添加少量Zr可使Cu-15Cr-0.1Zr的抗拉强度提高约15%;Zr的加入使复合材料的抗软化温度提高了50℃左右。     

精铸涡轮叶片蜡模模具型面优化设计方法

提出一种基于有限元法的精铸涡轮叶片蜡模模具型腔优化设计方法。首先,计算出涡轮叶片在凝固和冷却过程中的非均匀、非线性收缩变形量;然后,基于本文提出的位移场反向迭代算法,确定优化的蜡模模具型腔。以A356合金涡轮叶片为例,采用提出的涡轮叶片模具型腔优化设计系统,经过精度评估,尺寸误差得到了大幅度降低。数值模拟与实验结果吻合良好,经过4次迭代优化,涡轮叶片的总体形状误差从0.515815mm降低至0.001978mm。     

A Comparison of Aging Kinetics of New and Rejuvenated Conventionally Cast GTD-111 Gas Turbine Blades

Two industrial gas turbine blades made from a conventionally cast Ni-base superalloy GTD-111, one new and the other rejuvenated, were removed from the same machine after a particular operational cycle for an examination in order to determine the effect of rejuvenation on the material’s behavior during service. It was found that service-induced changes in the microstructure, such as γ′-phase coarsening and coalescence, excessive grain-boundary secondary M₂₃C₆ carbides formation, and primary MC carbides decomposition, were noticeably more advanced in the rejuvenated blade. The stress-rupture life of the rejuvenated blade decreased significantly compared to that of the new blade after the same number of hours in service. The cause of this decrease appears to be related to a release of additional amounts of carbon and carbide-forming elements into the matrix during rejuvenating heat treatment as a result of the primary MC carbide decomposition.     

Ag对Cu-10Fe-0.15Zr原位复合材料微观结构及性能的影响

研究了Cu-10Fe-0.15Zr、Cu-10Fe-2Ag-0.15Zr合金微观组织及性能。测定了在不同条件下试验合金的强度和电导率;并利用扫描电镜对材料的微观组织结构进行了观察和分析。结果表明：Cu-10Fe-0.15Zr、Cu-10Fe-2Ag-0.15Zr原位复合材料经（450~500）℃×1 h的最终退火处理,可获得较好的导电性和强度。热稳定性测试表明进行固溶处理后的形变Cu-10Fe-0.15Zr、Cu-10Fe-2Ag-0.15Zr原位复合材料抗软化温度能提高到450~500℃左右。当退火温度低于500℃时,导电率随着温度的升高而升高,而当温度高于这个温度,导电率逐渐下降。Cu-10Fe-2Ag-0.15Zr形变原位复合材料中间退火温度在450℃左右时,可获得最佳的综合性能,抗拉强度1056 MPa、导电率75%IACS、抗软化温度高于450℃。Cu-10Fe-2Ag-0.15Zr合金中添加微量合金元素Ag可使材料的极限抗拉强度增大,并改善材料的热稳定性,但导电率略有提高。     

Multiscale modelling and simulation of single crystal superalloy turbine blade casting during directional solidification process

As the key parts of an aero-engine,single crystal（SX）superalloy turbine blades have been the focus of much attention.However,casting defects often occur during the manufacturing process of the SX turbine blades.Modeling and simulation technology can help to optimize the manufacturing process of SX blades.Multiscale coupled models were proposed and used to simulate the physical phenomena occurring during the directional solidification（DS）process.Coupled with heat transfer（macroscale）and grain growth（meso-scale）,3D dendritic grain growth was calculated to show the competitive grain growth at micro-scale.SX grain selection behavior was studied by the simulation and experiments.The results show that the geometrical structure and technical parameters had strong influences on the grain selection effectiveness.Based on the coupled models,heat transfer,grain growth and microstructure evolution of a complex hollow SX blade were simulated.Both the simulated and experimental results show that the stray grain occurred at the platform of the SX blade when a constant withdrawal rate was used in manufacturing process.In order to avoid the formation of the stray crystal,the multi-scale coupled models and the withdrawal rate optimized technique were applied to the same SX turbine blade.The modeling results indicated that the optimized variable withdrawal rate can achieve SX blade castings with no stray grains,which was also proved by the experiments.     

温度和压力对1Cr12Mo钢汽轮机叶片微观组织的影响

为了研究服役条件下的汽轮机叶片的微观组织演化行为,利用X射线衍射仪、光学显微镜、扫描电镜和透射电镜等手段详细表征了退役1Cr12Mo钢高压动叶片的微观组织结构,进而分析了不同温度和压力对微观组织的影响规律。试验结果表明,适当的应力能促进板条内部尤其是边界析出相弥散分布,维持细小组织特征;细小弥散的析出相能够延缓位错束集和位错胞亚晶的形成。位错胞亚晶的形成显著地降低位错密度;温度对马氏体及位错结构影响不大,但显著提高碳化物的长大速度。     

Evaluation of service-induced damage and restoration of cast turbine blades

Conventionally cast turbine blades of Inconel 713C, from a military gas turbine aircraft engine, have been investigated with regard to service-induced microstructural damage and residual creep life time. For cast turbine blades, service life is defined by statistical values. The statistical methods can prove to be uneconomical, because safe limits must be stated with regard to the statistical probability that some blades will have higher damage than normal. An alternative approach is to determine the service-induced microstructural damage on each blade, or a representative number of blades, to better optimize blade us-age. Ways to use service-induced γ rafting and void formation as quantified microstructural damage pa-rameters in a service lifetime prediction model are suggested. The damage parameters were quantified, in blades with different service exposure levels, and correlated to remaining creep life evaluated from creep test specimens taken from different positions of serviced blades. Results from tests with different rejuvenation treatments, including hot isostatic pressing andJor heat treatment, are discussed briefly.     

Cu-Cr原位复合材料组织性能研究

采用感应加热熔炼及通过热锻和线拉变形结合中间热处理制备了Cu-15％Cr原位复合材料，用SEM和TEM等技术对形变Cu—Cr原位复合材料的Cr纤维形成过程、立体形态进行了分析。结果表明，在变形过程中Cr树枝晶发生转动，平行于线轴方向排列；Cr纤维立体形态则为卷边的薄片状。测定了形变Cu—Cr原位复合材料的抗拉强度，分析表明，强度随变形量的增加而提高，与纤维相间距呈Hall—Patch关系。     

变形方式对Cu-8.3Fe-1Ag形变原位复合材料组织性能的影响

分别采用冷拉拔和冷轧变形并结合中间退火工艺,制备了丝状和带状形变Cu-8.3Fe-1Ag原位复合材料。用SEM、精密万能试验机、显微硬度计和电阻测量仪对两种变形方式下试样的微观组织、力学性能和导电性能进行了比较研究。微观组织观察表明:冷拉拔和冷轧变形试样的横截面组织形貌有显著差异,前者为基体上分布着弯曲、扭折、交叠的蠕虫状相,后者为基体上定向排列着与冷轧方向平行的平直颗粒相。力学性能和导电率测试结果表明:相同应变量下,冷拉拔变形的抗拉强度、硬度均高于冷轧变形,但二者的导电率几乎相同。应变量达到6.70时,二者的抗拉强度/硬度/导电率分别达到838 MPa/149 HV/58%IACS和924 MPa/160 HV/58%IACS。