GH169合金显微组织对合金裂纹扩展速率的影响

对四种工艺（普通工艺、高强工艺、直接时效工艺、超细晶工艺）的Ｇ上６９合金的力学性能和６５０℃裂纹扩展速率进行了测试和对比分析。结果表明：晶粒细化和适量的颗粒状、短棒状δ相的晶界析出使合金６５０℃持久塑性明显提高，使合金６５０℃在纯蠕变和以蠕变损伤为主的疲劳－蠕变互作用条件下具有最低的理解纹扩展速率。     

热处理对GH742合金组织和力学性能的影响

研究了不同热处理制度对ＧＨ７４２高温合金组织和力学性能的影响。结果表明,调整固溶处理制度可明显改变晶粒度和γ＇形态。控制固溶处理温度,供γ＇相不完全溶解,可以阻止晶粒长大,而这种粗大γ＇相和时效过程中形成的细小γ＇相共存的组织具有良好的综合性能。时效处理可以改变γ＇相的数量和分布,时效温度越低,时间越长,则γ＇相数量越多,尺寸越小,使合金的强度上升,塑性降低。     

GH141合金的高温拉伸及持久性能

研究了热处理对GHl41合金760℃拉伸及900℃／170MPa持久性能的影响及合金显微组织与高温力学性能之间的关系。结果表明，GH141合金的760℃屈服强度σ0.2^760与晶粒平均直径D之间仍符合Hall—Petch关系；γ′强化机制可用位错切绕转换模型描述；晶界碳化物的种类、数量和尺寸对合金的持久寿命影响显著；晶内强度与晶界强度的合理匹配也是获得高持久寿命的重要因素。     

GH37合金中γ‘相的变化及其影响

本文根据ＧＨ３７合金涡轮叶片延寿研究工作中的结果，讨论了γ＇相的尺寸、数量、稳定性、形状、化学组成以及它们对合金的性能和组织的影响，提出了使用叶片恢复热处理等调整途径。     

缓冷处理对FCH95合金显微组织的影响

研究了缓冷处理过程中ＦＧＨ９５合金显微组织的变化规律，解释了双冷速缓冷处理后合金的高温流变应力降低的原因，为ＦＧＨ９５合金锻前预热处理工艺提供了依据。     

两种优质GH4169合金的显微组织及其对持久性能的影响

本文研究了高强度和直接时效两种GH4169合金的微观组织和持久断裂性能,探讨了微观组织、持久性能和热机械处理工艺间的关系。研究表明晶粒度及δ相的数量和分布是控制GH4169合金持久性能的关键因素。     

GH864合金在超温条件下的组织性能变化

用复型技术和薄膜技术研究GH864合金在超温条件下γ'相尺寸和硬度与超温温度之间的变化关系.试验结果表明,当超温温度在800～950 ℃范围内,随温度的升高,晶界上析出碳化物减少,γ'相尺寸、数量及材料的硬度均明显降低.通过对复型样品和薄膜样品的γ'相尺寸测量结果进行对比分析,表明可以用复型法获取γ'相的尺寸代替薄膜的γ'相尺寸.     

稀土影响高温合金GH907性能的显微机理研究

研究了稀土对GH907合金的力学和物理性能的影响规律,优化了可善GH907合金缺口持久性能,高温抗氧化性能的合金体系,通过比较标准GH907合金和稀土GH907合金的显微组织和界面结构,提出了稀土提高合金性能的微观机理,稀土主要存在于合金的片状相中,使其含量,形态,分布和晶体结构发生改变,与基体之间界面晶格失配和界面应力大小大减小。     

热处理对GH783合金组织与性能的影响

研究了抗氧化型低膨胀高温合金GH783的热处理制度.结果表明:随着固溶温度的升高,晶粒有所长大,在1140℃固溶晶粒开始不均匀长大;室温拉伸强度有所下降,高温拉伸塑性有所升高,持久塑性在1115℃固溶时最高.随着β时效温度的升高,二次β相明显增多,γ′相也发生比较明显的变化;在845℃进行β时效,合金可以获得良好的组织和综合性能.     

Effect of Solidification Interface Morphologies on Microstructures of a Ni-base Superalloy

A cast Ni-base superalloy K5 wasdirectionally solidified and various solidification in-terfaces including plane front,cellular,cellular-dendritic and dendritic were obtained in awider range of G/R ratio by using improved highwithdrawal device and liquid metal cooling experi-mental sets.The precipitation pattern of some prin-cipal phases of the alloy and correlation of the vari-ous interfaces with microstructure were studied sys-tematically.It was indicated that the morphology ofsolidification interface of superalloy K5 varied withG/R ratio and that the solidification interfacemorphologies have a considerable effect on the fea-tures of phases both precipitated duringsolidification and post-solidification.Plane frontand cellular directional solidification of superalloyK5 lead to a substantial decrease of MC carbideand elimination of γ-γ'eutectic,but makeneedle-shape M_6C carbide precipitate easily duringageing treatment.The finer dendritic structuressolidified under the condition of higher cooling ratehave less dendritic segregation and idealmicrostructure.     

热处理工艺对SRR99镍基单晶高温合金组织和性能的影响

研究不同固溶处理温度和时效处理温度对SRR99镍基单晶高温合金的微观组织和持久性能的影响。利用扫描电镜和光学金相显微镜对显微组织进行表征和分析,利用GWT304常载拉伸蠕变试验机测试其持久性能。结果表明:随着一次时效温度的提高,二次γ′相尺寸逐渐增大,γ′相体积分数先增加后降低;随着固溶温度的提高,合金中残余共晶含量减少,偏析逐渐降低,在1050℃/150MPa条件下,合金的持久寿命呈现先增加后降低的趋势。     

镍基高温合金脱氧的研究

氧在高温合金中是作为有害杂质元素存在的,通常是疲劳裂纹的萌生地及扩展通道,从而影响高温合金的蠕变、持久强度等性能.本研究在现有条件下,确定了氧在镍基高温合金中存在主要形态为氧化铝夹杂,根据得到的实验数据分析和计算,初步研究了真空感应熔炼条件下碳和铝对镍基高温合金的脱氧机理, 实验中氧含量最低为0.0006%,达到了小于0.001%的目标值.     

镍基合金高温扩散阻挡层的研究进展

介绍了镍基合金高温扩散阻挡层的作用机理,重点综述了金属和陶瓷扩散阻挡层的国内外研究进展,比较了两类扩散阻挡层的差别,尤其是元素扩散阻挡能力和界面结合强度的差别,最后指出了镍基合金高温扩散阻挡层的发展方向.     

镍基铸造高温合金热等静压处理的研究

就热等静压处理对镍基铸造高温合金的缺陷消除、组织和力学性能的改善作了研究。研究结果表明，通过热等静压处理后的合金，不仅可有效地消除合金中的缺陷（疏松和气孔），获得致密的合金，而且还可改善合金的显微组织，提高合金的持久、拉伸和疲劳性能，显著地减小性能分散度。     

GH4706合金的动态再结晶与晶粒控制*

采用双锥压缩实验结合有限元数值模拟, 研究了变形温度、变形量对GH4706合金动态再结晶(DRX)与η相的影响, 分析了发生DRX的临界条件, 探讨了利用η相细化晶粒的方法。结果表明: GH4706合金DRX机制为应变诱发的不连续原始晶界弓出; 临界DRX温度(T_DRX)为975℃, 而临界变形量(ε_DRX)则取决于变形温度与变形生热。由于η相的溶解温度近于T_DRX, 当合金在略低于T_DRX温度变形时, 有部分η相残留, 具有阻碍亚晶界或晶界迁移的效果。由此, 对GH4706合金在变形温度低于T_DRX条件下进行大变形, 可利用η相与再结晶的交互作用, 细化合金晶粒。     

Desulphurization during VIM Refining Ni-base Superalloy using CaO Crucible

The variation of S content during VIM refining Ni-base superalloy using CaO crucible was studied. It was foundthat the desulphurization process could not be carried out by only using CaO crucible. The role of Al additionto desulphurization was also studied. Combining with the results of XRD and composition analysis of the CaOcrucible, the mechanism of desulphurization was proposed. Thermodynamical calculation about the reaction betweenthe interface of CaO crucible and liquid metal has been discussed. This work indicated that under proper refiningtechnology the S content in the liquid Ni-base alloy could be reduced from 3×10-5 to 2×10-6~4×10-6.     

Transient Liquid Phase Bonding of Ni—base Single Crystal Superalloy

The Ni-base single crystal superalloy was bonded by the transient liquid phase(TLP) bonding,using a Ni-base flexible metal cloth as an insert alloy.TLP bonding of superalloy was carried out at 1473-1523K for 0.5-24h in vacuum.The [001] orientation of each test specimen was aligned perpendicular to the joint interface.The bonded region was observed by optical microscopy, and the microstructural and compositional analyses across the bonded interlayer were performed by using a scanning electron microscopy(SEM) .The electron back scattering diffraction(EBSD) method was applied to determine the crystallographic orientation.The resultsindicated that the chemical homogeneity across the bonded region can be achieved,and γˊphase both in the bonded interlayer and in the superalloy substrate is almost identical,while the bonded interlayer had almost matched the crystallographic orientation of the bonded substrates.     

Tensile and Fracture Behavior of DZ68 Ni-base Superalloy

The tensile and fracture behavior of DZ68 directionally solidified Ni-base superalloy was studied in the temperature range of room temperature (RT) to 1000°C. The fracture mode was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show the tensile strength and yield strength of DZ68 alloy increase slightly with increasing temperature, so that at 760°C its reach maxima value: 1214 and 1019 MPa, respectively. When the experimental temperature is higher than...