Jiarong LI
,
Dingzhong TANG
,
Riling LAO
,
Shizhong LIU
,
Zhongtang WU
材料科学技术（英文）
The slabs of a single crystal superalloy were poured with 2.2% Re, 3.2% Re and 4.2% Re and other element contents of the alloys were basically kept no changed. The effects of Re on the ultimate tensile strength, creep rupture life and rafting of a single crystal superalloy were studied. The results showed that with increasing Re content the ultimate tensile strength decreased but the plasticity increased at 649℃, and the creep rupture life remarkably increased while the plasticity decreased at 982℃/248.2 MPa, 1038℃/206.8 MPa and 1070℃/176.8 MPa for the alloy; on the microstructure aspect, with increasing the creep rupture life of the alloy the rafting was getting bigger and bigger at the same test condition, and the rafting suppressed creep and increased creep rupture life in this single crystal superalloy.
关键词:
Jiarong LI
,
Shizhong LIU
,
Hailong YUAN
,
Zhengang ZHONG
材料科学技术（英文）
The three-dimensional solidification simulation of the investment castings of single crystal hollow turbine blade at the withdrawal rates of 2 mm/min, 4.5 mm/min and 7mm/min has been performed with the finite element thermal analysis. The calculated results are in accordance with the experimental ones. The results show that with the increase of withdrawal rate the concave curvature of the liquidus isotherm is larger and larger, and the temperature gradients of the blades increase. No effects of withdrawal rate on the distribution of the temperature gradients of the starter and helical grain selector of the blades are observed at withdrawal rates of 2 mm/min, 4.5 mm/min and 7 mm/min. The relatively high temperature gradient between 500ºC/cm and 1000 ºC/cm in the starter and helical grain selector is obtained at three withdrawal rates.
关键词:
Single crystal
,
null
,
null
Jiarong LI
,
Shizhong LIU
,
Zhengang ZHONG
材料科学技术（英文）
The three dimensional solidification simulation of the single crystal investment castings at withdrawal rates of 2 mm/min, 4.5 mm/min and 7 mm/min was performed with the finite element thermal analysis method. The calculated results were in accordance with the experimental ones. The results showed that with the increase of withdrawal rate the concave curvature of the liquidus isotherm was bigger and bigger and the temperature gradient of the castings decreased. No effects of withdrawal rate on the distribution of the temperature gradient of the starter and helical grain selector of the castings were observed at withdrawal rates of 2 mm/min, 4.5 mm/min and 7 mm/min. The relatively high temperature gradient between 500°C/cm and 1000°C/cm in the starter and helical grain selector was obtained at three withdrawal rates. The study indicates the three dimensional solidification simulation by finite element method is a powerful tool for understanding solidification and predicting defects in single crystal investment castings.
关键词:
Single crystal
,
null
,
null
李志宏
,
柳卫平
,
白希祥
,
郭冰
,
连钢
,
颜胜权
,
王宝祥
,
陆昀
,
曾晟
,
苏俊
原子核物理评论
doi:10.3969/j.issn.1007-4627.2005.01.006
利用8Li次级束测量了质心系能量7.8 MeV 2H(8Li, 9Li)1H反应的角分布, 导出了8Li(d, p)9Li反应的天体物理S因子及9Li→8Li+n虚衰变的渐近归一化系数.
关键词:
8Li(d,p)9Li反应
,
角分布
,
天体物理S因子
,
渐近归一化系数
HUANG Jianshun CHEN Junming Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
China Research Associate
,
Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai 200050
,
China
金属学报(英文版)
Crystal structure of γ-Li_xFe_2O_3,inserted Li electrochemically,was studied by Moss- bauer spectroscopy together with X-ray diffraction,XPS and electrochemical method,On the insertion of Li at low current density,the crystal structure is keeping original spinel; while at higher current density or by thermal activation,owing to violent movement of Li~+ ions,part of crystal structure transforms into rock type similar to face-centered cubic structure of ferrous oxide.The transition channels during insertion of Li~+ ions and limitation of Li~+ ions inserted were discussed.
关键词:
null
,
null
,
null
Journal of Materials Research
The effect of Li(3)N additive on the Li-Mg-N-H system was examined with respect to the reversible dehydrogenation performance. Screening Study with varying Li(3)N additions (5, 10, 20, and 30 mol%) demonstrates that all are effective for improving the hydrogen desorption capacity. Optimally, incorporation of 10 mol% Li(3)N improves the practical capacity from 3.9 wt% to approximately 4.7 wt% hydrogen at 200 degrees C, which drives the dehydrogenation reaction toward completion. Moreover, the capacity enhancement persists well over 10 de-/rehydrogenation cycles. Systematic x-ray diffraction examinations indicate that Li(3)N additive transforms into LiNH(2) and LiH phases and remains during hydrogen cycling. Combined structure/property investigations suggest that the LiNH(2) "seeding" should be responsible for the capacity enhancement, which reduces the kinetic barrier associated with the nucleation of intermediate LiNH(2). In addition, the concurrent incorporation of LiH is effective for mitigating the ammonia release.
关键词:
complex hydrides;improvement;mixtures;imides;amide;h-2
MANG Weishi WANG Guozhi ZHANG Yongchang HU Zhuangqi SHI Changxu Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Yongchang Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
A rapidly solidified microcrystalline Al-Li-Cu-Mg-Zr alloy and its superplasicity have been investigated.An optimum tensile elongation of 585% was obtained at 540℃ and strain rate 1.67×10~(-2)s~(-1).The superplastic Al-Li alloy is manufaetured using thermomechanical pro- cessing:solution,overaging,warm rolling and recrystallization.Microstructural changes in thermomechanical processing and cavitation occurred during superplastic deformation have been observed.The superplastic failure of alloy may be caused mainly by nucleation and growth of cavities as well as the linkage around grains.
关键词:
superplasticity
,
null
,
null
,
null
