Jianping NIU
,
Kenu YANG
,
Tao JIN
,
Xiaofeng SUN
,
Hengrong GUAN
,
Zhuangqi HU
材料科学技术（英）
The variation of S content during VIM refining Ni-base superalloy using CaO crucible was studied. It was found that the desulphurization process could not be carried out by only using CaO crucible. The role of Al addition to desulphurization was also studied. Combining with the results of XRD and composition analysis of the CaO crucible, the mechanism of desulphurization was proposed. Thermodynamical calculation about the reaction between the interface of CaO crucible and liquid metal has been discussed. This work indicated that under proper refining technology the S content in the liquid Ni-base alloy could be reduced from 3×10-5 to 2×10-6-4×10-6.
关键词:
Ni-base superalloy
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null
,
null
,
null
Wen LI
,
Tao JIN
,
Xiaofeng SUN
,
Yi GUO
,
Hengrong GUAN
,
Zhuangqi HU
材料科学技术（英）
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 1473~1523 K for 0.5~24 h 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 results indicated that the chemical homogeneity across the bonded region can be achieved, and γ′ phase 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.
关键词:
Single crystal superalloy
,
null
,
null
,
null
Hua WEI
,
Xiaofeng SUN
,
Qi ZHENG
,
Guichen HOU
,
Hengrong GUAN
,
Zhuangqi HU
材料科学技术（英）
A numerical method has been developed to extract the composition-dependent interdiffusivity from the concentration profiles in the aluminide coating prepared by pack cementation. The procedure is based on the classic finite difference method (FDM). In order to simplify the model, effect of some alloying elements on interdiffusivity can be negligible. Calculated results indicate the interdiffusivity in aluminide coating strongly depends on the composition and give the formulas used to calculate interdiffusivity at 850, 950 and 1050ºC. The effect on interdiffusivity is briefly discussed.
关键词:
Interdiffusivity
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null
,
null
Mengjin LI
,
Xiaofeng SUN
,
Hengrong GUAN
,
Xiaoxia JIANG
,
Zhuangqi HU
材料科学技术（英）
(Ni,Pd)Al coating, prepared by low pressure pack cementation on the Ni-base superalloy M38 where Pd-20 wt pct Ni alloy was predeposited, consists of a single β-(Ni,Pd)Al phase. The initial isothermal oxidation behavior of (Ni,Pd)Al coating was investigated by TGA, XRD, SEM/EDS at 800-1100℃. Results show that oxidation kinetics accord preferably with parabolic law at 800, 900 and 1100℃, but not at 1000℃. β-Al2O3 was observed at 800-1100℃. It is found that Pd plays an important role in accelerating the diffusion of Ti from the substrate to the coating surface in the aluminide coating.
关键词:
(Ni
,
null
,
null
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null
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null
Chao YUAN
,
Fengshi YIN
,
Xiaofeng SUN
,
Hengrong GUAN
,
Zhuangqi HU
材料科学技术（英）
Effect of phosphorus on the microstructure and high temperature properties of a cast Ni-base superalloy M963 has been investigated. SEM observation and EDS analysis showed that P was mostly enriched in the interdendritic region, and the P-rich phase was formed in the front position of finally solidified eutectics in high P doped alloys. It was found that the P-rich phase, as preferred initiation and propagation site of cracks, could aggravate the fracture process at high temperature in high P doped alloys.Consequently, high P addition would reduce remarkably the ductility and creep life of M963 superalloy at high temperature.
关键词:
Phosphorus
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null
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null
,
null
周镇
,
艾育华
,
孔文俊
工程热物理学报
本文利用双腔泄压式定压燃烧弹,研究了高压下典型IGCC合成气的层流火焰传播特性,得到了不同压力(0.1～1 MPa)和不同当量比下(0.6～3.0)合成气的层流火焰传播速度和Markstein长度.实验结果表明,层流火焰传播速度随当量比先增加后减少,随压力的增加而减小.Davis和Sun机理能较好地预测高压下合成气层流火焰的传播速度.Markstein长度随当量比的增加而增加,随压力的增加而减小.
关键词:
合成气
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球形火焰
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层流火焰传播速度
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Markstein长度
程杰锋
,
唐广波
,
刘正东
钢铁研究学报
选取了现有典型的C-Mn钢相变过程的物理冶金模型,包括5组孕育期模型、7组相变动力学方程模型、5组相变后铁素体晶粒尺寸模型.利用自行开发的组织性能预报系统软件模拟计算了在3组实际冷却工艺条件下各模型的奥氏体转变过程,并对各模型进行了评价.结果表明,对于所设定的成分和工艺条件,适用性较好的孕育期模型是Kwon所提出的模型;适用性较好的动力学方程模型是Liu、Donnay和Sun所提出的模型;适用性较好的铁索体晶粒尺寸模型是Hodgson所提出的模型.
关键词:
孕育期
,
相变
,
适用性分析
朱亮
,
肖毅
复合材料学报
为满足在工程应用中对建立拉压性能不同纤维增强复合材料的非线性本构理论的需要,考虑静水压影响的Drucker-Prager屈服准则与各向异性的Hill屈服准则相结合,提出了广义Hill屈服准则,并推广到Sun-Chen的单参数塑性模型中,建立了考虑拉压异性复合材料的非线性统一本构方程.实验验证结果表明,运用本文中所建立的本构模型能够很好地描述碳纤维/环氧(IM600/Q133)复合材料在偏轴拉伸和压缩载荷作用下的非线性响应.
关键词:
单向复合材料
,
非线性响应
,
不同屈服强度
,
本构方程
,
偏轴拉伸-压缩载荷
