LIANG Yong ZENG Xiaoyan TONG Baiyun SI Zhongyao Institute of Metal Research
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Academia Sinica
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Shenyang
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China LIANG Yong
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Professor
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Institute of Metal Research.Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
The effect of the laser processing parameters on the composition uniformity and shape coefficient of fusion zone with laser surface alloyed Cr plated on medium carbon low alloy steel has been studied.It was found that the composition uniformity depends on the shape coefficient of fusion zone,and the later is a function of both power density and interaction time.If the power density is fixed to a certain value,the shape coefficient is directly,propor- tional to the interaction time.A completely,uniform molten pool can be obtained,when the shape coefficient is between 1.6 and 3.0.
关键词:
laser alloying
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Daolun CHEN B.Weiss R.Stickler University of Vienna
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Wahringer Street 42
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A-1090 Vienna
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AustriaZhongguang WANG State Key Laboratory for Fatigue and Fracture of Materials
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Institute of Metal Research.Academia Sinica
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Shenyang 110015
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China
材料科学技术（英文）
Near-threshold fatigue crack propagation behaviour of a cold-worked copper tested with distinct fa- tigue testing systems under different stress ratios has been investigated.The emphasis was placed on the evaluation of crack closure effect as well as the effective fatigue threshold,It was found that the fatigue threshold for R=0 is higher than those for R=-1 and R=0.4,for which almost the same threshold value was derived.Compared with the conventional closure evaluation method,the pro- posed new closure evaluation method can generally interpret the dependence of the fatigue thresh- old on stress ratio and loading condition,and leads to a higher and relatively constant effective fa- tigue threshold of about 3 MPa·m~(1/2) for the cold-worked copper at different stress ratios and loading conditions.
关键词:
near-threshold fatigue
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null
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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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Corrosion
This paper introduces the design of a localized corrosion rate monitoring instrument that can monitor and evaluate the maximum and stable localized corrosion rate of a nonpassivable metal in a corrosive environment by measuring the current density in a corrosion sensor with an occluded anode.
关键词:
instrument;localized corrosion rate;monitor
Juhua HUANG
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Jinjun RAO
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Xuefeng LI
材料科学技术（英文）
Sheet metal forming is widely applied to automobile, aviation, space flight, ship, instrument, and appliance industries. In this paper, based on analyzing the shortcoming of general finite element analysis (FEA), the conception of parametric finite element analysis (PFEA) is presented. The parametric finite element analysis, artificial neural networks (ANN) and genetic algorithm (GA) are combined to research thoroughly on the problems of process parameters optimization of sheet metal forming. The author programs the optimization scheme and applies it in a research of optimization problem of inside square hole flanging technological parameters. The optimization result coincides well with the result of experiment. The research shows that the optimization scheme offers a good new way in die design and sheet metal forming field.
关键词:
Sheet metal forming
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