GUO Shouren LU Dezhong GUO Jianting Institute of Metal Research
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Academia
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Shenyang
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ChinaWU Xi Fushun Steel Works
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Fushun
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China Associate Professor
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Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
The mechanical properties and microstructure of an Fe-base superalloy GH35A have been examined after aging at 650—750℃ for 100—10000 h.The tensile strength of the alloy changes no more with aging temperature and the time at room temperature,but the ductility and impact toughness at room temperature,as well as the stress-rupture life up to 700℃ de- crease slowly during aging up to 10000 h The initiation time to worsen its properties becomes shorter as the aging temperature rises.The variation of the mechanical properties of the alloy was found mainly depending on the formation,morphology,distribution and characteristic of the σ-phase precipitation.
关键词:
superalloy
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CHEN Liangshi
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GAO Xuejie
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FENG Tao
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LIU Minzhi Corrosion Science Laboratory
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Institute of Corrosion and Protection of Metals
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Academia
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Sinica Shenyang
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China
金属学报(英文版)
Corrosion fatigue under the load of low frequency and bigh mean stress has been generally defined as stress corrosion fatigue(SCF).It is a specific failure process due to the inter- action between stress corrosion cracking(SCC) and corrsion fatigue(CF),the effects of which on fracture characteristics,including crack initiation and propagation.service life and cracking mode have not been investigated systematically.The purpose of this pa- per was to study the environment-sensitive fracture behaviour of OCr18Ni9Ti austenitic stainless steel under the load of different fiequencies and high mean stress in boiling MgCl_2 solution.The interaction between SCC and CF would be emphasized.
关键词:
stress corrosion eracking
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MA Zongyi YAO Zhongkai Harbin Institute of Technology
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Harbin
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China
金属学报(英文版)
The SiC_w/Al composite prepared by squeeze casting has a combination of superior room temperature specific strength and modulus together with excellent thermal properties.The extrusion can make an improvement on the strength and ductility of the composite from 582 MPa as squeeze casted up to 639 MPa,and on the transformation from isotropic to the anisotropic structure.This seems to be explained by the orientation of whiskers and the densification of dislocations in matrix.TEM observation indicates that the stacking fault is the usual planar defect on the SiC_w surface. composite;;SiC whisker;;Al alloy;;microstructure
关键词:
composite
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LIU Zhonghao CHEN Lian Institute of Metal Research
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Academia Sinica
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Shenyang
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China
金属学报(英文版)
Within the range of 77 to 295 K,the strength and plastieity of 18Ni maraging steel increase with decreasing temperature and decrease with increasing hydrogen content.The susceptibility to hydrogen embrittlement of the maraged specimens is superior to solid solution ones.The dislocations after plastically deforming will tangle into dislocation cells which reduce thermselves in size as the temperature decreases,and coarsen as the hydrogen content in- creases.No cryogenie deformation twin was found.The tensile fracture surfaces of the solu- tion and maraged specimens containing 5.90 ppm hydrogen under 295 to 223 K are revealed as quasi-cleavage and intergranular features respectively and as transgranular ones under other experimental conditions.The influence of hydrogen on the mechanical behaviour of steel and the mechanism of hydrogen induced deformation and fracture are discussed. Research Assistant, Institute of Metal Research,Academia Sinica, Shenyang 110015,China
关键词:
maraging steel
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ZHOU Jiankun LIU Xianghuai CHEN Youshan WANG Xi ZHENG Zhihong HUANG Wei ZOU Shichang Shanghai Institute of Metallurgy
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Academia Sinica
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Shanghai
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China
金属学报(英文版)
The TiN films were synthesized with an alternate process of depositing titanium from a E-gun evaporation source and 40 keV N~+ bombarding onto the target.It is shown from the composi- tion analysis and structure investigations using RBS,AES,TEM,XPS and X-ray diffraction spectrum that the formed fihns are mainly composed of TiN phase with grain size of 30—40 nm and without preferred orientation,the nitrogen content in the film is much less than that in case without N~+ bombarding,and an intermixed region about 40 nm thick exists between the film and the substrate.The films exhibt high microhardness and low friction. ZHOU Jiankun,Ion Beam Laboratory,Shanghai Institute of Metallurgy,Academia Sinica, Shanghai 200050,China
关键词:
TiN film
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NING Hua ZHANG Lixin Institute of Corrosion and Protection of Metals
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Academia Sinica
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Shenyang
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China
金属学报(英文版)
The segregation behaviour of P and its effect on structure of 70%-reduction cold rolled Fe-P alloys containing different contents of P,e.g.,0.007,0.06 and 0.09% P,during annealing at 200-700℃ under vacuum have been studied by means of metallography and EPMA.The P was found to segregate preferentially along dislocation line during recovery annealing.The P-riched dislocation densing region,the P-depleted region and the sub-grain-like boundary thus formed.The nuclei grow preferentially during recrystallization in such region that the P segregation is more evident and the residual strain by dislocation densing increases to large extent.After recrystallizing,the P segregates along grain boundaries and makes the grains in alloy fine. Engineer,Institute of Corrosion and Protection of Metals,Academia Sinica,Shenyang 110015,China
关键词:
P
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