ZHANG Rong
,
ZHOU Lubin
,
Northwestern Polytechnical University
,
Xi'an
,
ChinaZHENG Wenlong
,
HUA Huizhong
,
Shanghai Research Institute of Materials
,
Shanghai
,
China ZHANG Rong
,
Lecturer
,
Department of Applied Physics
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China
金属学报(英文版)
The behaviour towards corrosion fatigue of low carbon bainite steel with various microstructures after tempered at different temperatures has been examined. The susceptibility of the steel to corrosion fatigue may be improved by tempering at 300℃.
关键词:
corrosion fatigue
,
null
,
null
,
null
K. Zhang
,
YQ. Wang
,
B.L. Zhou
,
YH. Zhou and H.L. Li (Institute of Metal Research
,
Chinese Academy of Scie11ces
,
Shenyang 110015
,
China International Center of Materials Physics
,
Chinese Academy of Sciences
,
Shenyang 110015
,
China Dept. of Materials Science and Engineering
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The mechanical properties and deformation mechanisms of unidirectional carbon fiber reiopreed magnesium composites under tensile loading are studied. Two different materials are used as fiber coatings: a single silica and a gradient C/SiC/SiO2. The results show that, under the same preparation conditions, composite with the former coating is broken in a non-cumulative mode and its failure stress is rather low. Conversely, the latter coating demonstrates much better efficiency and the cormsponding composite is broken in a cumttlative mode.
关键词:
tensile properties
,
null
,
null
Q. Y Pan
,
WD. Huang
,
YM. Li
,
X. Lin
,
YH. Zhou and X.C. Yan( State Key Lab. of Solidification Processing
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China ( Laser Processing Center
,
Tianjin College of Textile Technology
,
Tianjin 300160
,
China )
金属学报(英文版)
A novel wide-band laser cladding system, with high rate of cladding, has been developed in the present work. The system mainly consisted of a 5kW CO2 laser, an automatic Fowder feeder and a wide-band scanning rotative polygon mirmr which can produce a linear or rectangular focused laser beam. Using this system, a Ni-Cr-Si-B alloy powder was cladded on the sudece of tgpe 321 austenitic stainless steel in onder to improve its wear and cormsion resistance. The pitting cormsion, high temperuture oxidation and wear tests were conducted in onder to evaluate the propertles of the laser cladded layer. The results demonstrated that the cladded layer can significantly improtte the adhesive wear and pitting cormsion resistance of the substmte. Moreover,the cladded layer exhibited good oxidafion resistance, which is almost the same as that of GMR-235D N-based superalloy.
关键词:
austenitic stainless steel
,
null
,
null
,
null
N. Wang and B. Wei (Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)(Laboratory of Materials Science in Space
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The Ag-50wt%Cu hypereutectic alloy was solidified in a 3m drop tube. It is .revealed that with the decrease of droplet size, the strnctural morphology transformed from the dendrites with long trunk and thin short secondary arms to fine dendritic structures.The calculations based on LKT dendritic growth model indicate that dendritic growth is dominantly controlled by solute diffusion within the whole undcreooling regime.However, the influence of thermal diffusion-controlled growth becomes stronger above a critical undercooling about 268K. The refinement of dendritic structure is caused by large amounts of nuclei within droplet. Moreover, it is estimated that when droplet diameter is smaller than 300μm, the undercooling and growth velocity are fanger than 268K and 290mm/s respectively, while the solute impping effect may occur. Compared with Ag-15wt%Cu hypoeutectic alloy, there is no evident feature of dendritic-toequiaxed transition for Ag-50wt%Cu hypereutectic alloy, which is consistent with the calculation results of dendritic breakap time.Keuwords: Ag-Cu alloy; rapid solidification; undercooling; dendritic growth
关键词:
Ag-Cu alloy
,
null
,
null
,
null
R.Shi
,
G.X.Hu
,
H.J.Li and M.K.Kang (The State Education Commission Open Research Laboratory for High Temperature Materials and Testing
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)(Department of Materials Science and Engineering
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
The steady-state creep behavior of unidirectional C/C(1-D-C/C) composite with pyrolytic carbon matrix was investigated at high temperatures up to 2160℃ and under tensile stress from 133.83 to 213.46MPa. Based on the creep experiment of single specimen method, the apparent activation energy and the stress exponent for steadystate creep were determined by the use of a self-made apparatus and an auto-testing system. Value of apparent activation volume is provided and the creep mechanism has also been discussed.
关键词:
1-D-C/C
,
null
,
null
H. Yu
,
Z.X. Lin and Y.H. Zhou 1) Department of Materials Engineering
,
Nanchang Institute of Aeronautical Technology
,
Nanchang 330034
,
China 2) The State Key Laboratory of Solidification Processing
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China
金属学报(英文版)
Based on the principle of infiltration mechanics in porous medium, high Reynolds number infiltration of liquid aluminum in porous medium has been investigated. Combined with the test results of hydraulic simulation, the mathematical model of the high Reynolds number infiltration of liquid aluminum in porous medium has been established, and it is found that infiltration is characterized by its second order nonlinear. The calculated results based on the model are in good agreement with those of the hydraulic simulation and the aluminum alloy infiltration. The way of high speed infiltration under medium pressure has been put forward to fabricate porous aluminum alloy with thin holes of 0.4mm diameter.
关键词:
infiltration
,
null
,
null
X. Q. Zhang
,
Y. H. Peng
,
M. Q. Li and X. Y. Ruan( 1)Department of Plasticity Technology
,
Shanghai Jiao TOng University
,
Shanghai 200030 2)School of Material Science and Engineering
,
Northwestern Polytechnical University
,
Xi' an 710072
,
China)
金属学报(英文版)
In the present research, artificial artificial networks hare be applied to establish the constitutive rela- tionship model of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Cr (wt - % ) alloy. In the first stage of the re- search, an isothermal compressive experiment using Thermecmastor - Z hot simulator is studied to ac- quire the flow stress at different deformation temperature,equivalent strain and equivalent strain rate. Then,a feed - forward neural network is trained by using the experimental data.After the training process is finished, the neural networks become a knowledge-based constitutive relationship system. Comparison of the predicted and experimental results results shows that the neural network model has good le- arning precision and good generalization.The neural neural network methods are found to show much better agreement than existing methods with the experiment data, and have the advantage of being able to deal with noisy for or data with strong non - linear reationships. At last, this model can be aused to simulate the flow behavior of Ti - 5Al - 2Sn - 2Zr - 4Mo - 4Ca alloy.
关键词:
titanium alloy
,
null
,
null
,
null
J. Feng
,
W.D. Huang
,
X. Lin
,
T. Li
,
Y.F. Xue and Y.H. Zhou(State Key Lab. of Solidilication Processing
,
Northwestern Polytechnical University
,
Xi'an 710072
,
China)
金属学报(英文版)
In order to investigate the response of cellular spacing to the variation of growth velocity under near-rapid directional solidification condition, Al-0.53wt%Zn alloy is directionally solidified with Bridgman apparatus. The results show that at the given temperature gradient the obtained microstrvctures are all cells and there exists a wide distribution range of cellular spacing. The maximum, λmax, minimum, λmin, and average cellular spacing, λ, as functions of growth rate, V, can be given by λmax=948.51V-0.4961, λmin= 661.16V-0.5015 and λ=412.41V-0.5049, respectively. The experimental results are compared with that predicted by KGT model, and a good agreement is found. Moreover,it is found that the average cellular spacing is also remarkably history-dependent.
关键词:
Al-Zn alloy
,
null
,
null
,
null
X.W.Yin
,
L.F.Cheng
,
L.T.Zhang
,
W.C.Zhou and Y.D.Xu State Key Laboratory of Solidification Processing
,
Northwestern Polytechnical University
,
Xi′an 710072
,
China
金属学报(英文版)
Strong, tough, and almost fully dense C fiber reinforced celsian matrix composites have been fabricated by impregnation of the fiber tows with the matrix slurry, winding on a drum, drying, stacking the prepreg tapes in the desired orientation, and hot pressing. The monoclinic celsian phase in the matrix was produced in situ, during hot pressing, from amphosous BAS. The unidirectional composites having ≈20 vol% of fibers exhibited graceful failure with extensive fiber pullout in three point bend tests at room temperature. Values of ultimate flexural strength and fracture toughness were 379MPa and 8 3MPa·m 1/2 , respectively.
关键词:
barium aluminosilicate
,
null
,
null
,
null
,
null
