Author C.D. Zhou1
,
2)
,
J.X. Yu1)
,
X.P. Dong1)
,
Y.H. Zhang1)
,
C.Q. Sun3) and T.F. Li4) 1) The State Education Commission Open Research Laboratory for High Temperature Materials and Testing
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China2) Shanghai Enhanced Lab of Ferrometallurgy
,
Shanghai University
,
Shanghai 200072
,
China3) Institute of Aeronautical Materials
,
Beijing 100095
,
China 4) Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
ChinaManuscript received 18 October 1998
金属学报(英文版)
An investigation has been made on the tensile fracture behavior of oriented single crystal DD100 superalloy at 850. The appearance of the fracture surface of DD100 reflects the glide plane decohension fracture mechanism, which is different from the fracture of oriented DD100. The tensile strength and elongation are lower than the oriented DD100. Oxygen in air has little effect on the strength of DD100 but reduces the tensile elongation obviously. Oxygen does not affect the fracture mode of DD100 but strongly accelerates the process of fracture.
关键词:
single crystal superalloy
,
null
,
null
Y.Z. Yang
,
Y.H Luo
,
Q.S. Li
,
Y.L. Zhu
,
X.M. Ma
,
Y.D. Dong and Y.Z. Chuang(Department of Materials Science and Engineering
,
Guangdong University of Technology
,
Guangzhou510090
,
China)(Guangdong Educational College
,
Guangzhou 510084
,
China)(Department of Materials Science and Engineering
,
Shanghai University
,
Shanghai 200072
,
China)(Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
The structural transformation in Fe-Cu powder induced by mechanically driven alloying has been monitored by the lattice constant measurements and Mossbauer spectroscopy. For the samples with Cu higher than 75at.% Mossbauer the spectra show a broad paramagnetic doublet; for samples with 50 and 60at.%Cu a new broad ferromagnetic sextet; for those with less than 30at.%Cu similar to those of α-Fe. The main peaks of the hyperfine field distribution significantly broaden and shift to a lower position with increasing Cu content due to the complex environments of iron atoms in the solid solutions and the reduction in the nearest neighbor Fe of a cental Fe atom, respectively. The saturation magnetization of Fe-Cu alloys monotonously decreases with Cu content. The complex composition dependence of coercive field for the milled samples is discussed with respect to the solid dissolution, grain size, interfacial state etc.. The increase of lattice constants with the solute content in the two terminal solid solutions has been explained by the volume-size factor theory or magnetovolume effect.
关键词:
mechanical alloying
,
null
,
null
,
null
Z. F. Wan
,
X.D. Hui
,
G.Q. Yuan
,
Y. S. Yang and X.C Chen (Shandong University of Technology
,
Jinan 250061
,
China)(Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Institute of Physics
,
The Chinese Academy of Sciences
,
Beijing 100080
,
China)
金属学报(英文版)
The initiation and propagation of the short fatigue crack in a 10vol% titanium carbide particulate reichreed cast Fe-26Cr-14Ni mathe coopsite at 1023K were investigated.It is shown that the titanium carbide particulate may hinder the crack propagation and fatigue fracture of the composite. The relationships between fatigue crack propagation rate and stress intensity factor are da/dN=4.2×10-c(△K)4 for the matrix alloy and da/dN=1.4×10-19(△K)c for the composite. The fatigue thresholds of the composite and mathe alloy are 78 and 3.2MPa.m1/2, respectively. Microcracks initiate at the intedece between titanium carbide particulate and austenite and then propagate in carkide particles. The fracture sudece of the composite shows a distinct transition from wavy and serated cleavage near the threshold regime to striation-type splitting in the stable fatigue crack propagation stage and to a veined morphology characteristic in unstable rapid region.
关键词:
fatigue crack
,
null
,
null
,
null
S.J. Zhao
,
Y.C. Wang
,
J.Q. You
,
Q.B. Yang
,
L.G. Zhou and H.Q. Ye (Department of Physics
,
Xiangtan University
,
Xiangtan 411105
,
China)(Laboratory of Atomic Imaging of Solids
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Department of Materials Science
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
A structural transition in the fcc ∑=5 (120)/[001] high-angle tilt grain-boundary(GB)is investigated by molecular-dynamics simulation. The calculations have been performed at various temperutures and the thermodynamic melting point Tm of the model system is determined by using a many-body potential fitted to copper. A thermal disorder transition in the GB region occurs well below the melting point. Our results indicate that such a transition is a continuous process and there is no evidence of premelting, which is entirely in accord with experiment results and theoretical prediction.Moreover we also observed that melting initiated at the interface and then propagated into the bulk quickly at or above Tm.
关键词:
moleculandynamics
,
null
,
null
J.H.Dong 1)
,
J.Y.Chen 2
,
3) and. C.N.Cao 1) 1) State Key Laboratory for Corrosion and Protection of Metals
,
Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China 2) The International Center for Materials Physics
,
CAS
,
Shenyang 110015
,
China 3) Shenyang Normal College
,
Shenyang 110031
,
China
金属学报(英文版)
The effect of chloride ion on the corrosion inhibition of iron caused by dencylamine(DA), dipentylamine(DDA) and dodecylamine(DPA) has been investigated by measuring the inhibitory coefficients for the anodic and cathodic processes at corrosion potential. It has been shown that the major synergistic inhibition effects between amines and chloride ions occur in the cathodic process, very weak in the anodic process. The anodic inhibition mechanism follows the competing adsorptive model, while the cathodic inhibition mechanism follows the cooperative adsorptive model.
关键词:
synergistic inhibition
,
null
,
null
J.L. Li
,
K.F. Wang
,
J. Li
,
Z.M. Yao and W. Ke(Fushun Petroleum Institute
,
Fushun 113001
,
China)(Department of Chemical Engineering
,
Zhejiang University
,
Hangzhou 310027
,
China)(Institute of Corrosion and Protection of Metals
,
The Chinese Academy of Sciences
,
Shengyang 110015
,
China)
金属学报(英文版)
Influence of hydrogen attack on mechanical and fatigue properties of 1020, 15CrMo and 2.25Cr-1Mo steels has been studied, which were exposed to gaseous hydrogen at pressure of 18MPa and 300-480℃ for up to 480h. The results of fatigue test showed that hydrogen attack (HA) resulted in an obvious change in fatigue properties of 1020 and 15CrMo steels, however, 2.25Cr-1Mo steel showed a lower susceptibility to hydrogen attack due to the addition of Cr and Mo. Fatigue crack behaviour for 1020 steel is attributed to hydrogen attack damage and the crack closure induced by the rough cracking surface, which lead to a valley on △Kth～HA% plot. The change in the fatigue behaviour of 15CrMo steel is possibly caused by severe surface decarburization.
关键词:
hydrogen attack
,
null
,
null
,
null
G.P. Li
,
D. Li
,
Y. Y. Liu
,
Q.J. Wang
,
S.X. Guan
,
and Q.C. Li (Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(School of Materials Science and Engineering
,
Harbin Institute of Technology
,
Harbin 150001
,
China)
金属学报(英文版)
The Ti-35V-15Cr-0.05C (wt% is a new nonburning titanium alloy. The test for alloy combustibility was carried out by using CO2 laser. A 430 watt and 6mm diameter laser spot impinges directly on the sample within normal atmospheric pressure and temperature. The results show that the ignition time of the nonburning titanium alloy is the longest in the eight examined titanium alloys, and is 3.5 times that of TC4 alloy. The ignition tempeerature of the nonburning alloy is 2991° C, and is higher than that of TC4 alloy by 1976°C. On the condition of high tempeerature and rich oxygen,the surface of alloy forms a melting layer which plays roles of oxygen insulation, heat insulation and burning products insulation. This is the mechanism of combustion resistance.
关键词:
Ti-35V-15Cr-0.05C (wt%) nonburning titanium alloy
,
null
Y.Z. Yang
,
Y.L. Zhu
,
Q.S. Li
,
X.M. Ma
,
Y.D. Dong and Y.Z. Chuang (Department of Materials Science and Engineering
,
Guangdong University of Technologyt Guangzhou 510090
,
China)(Depotment of Materials Science and Engineering
,
Shanghai University
,
Shanghai 200072
,
China)(Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
Nanocrystalline supersaturated solid solutions (Sa in Fe) with Sn content less than 50 at. %,and FeSn2 and Fe1.3Sn intermetallic compounds have been prepared by mechanical alloying of Fe and Sn mixture powders with composition of Fe1-xSnx (x≤0.5).The atomic alloying the formation and microstructure, especially the coordination environments, of the resultant alloys have been studied by X-ray diffraction, 57Fe and 119Sn Mossbauer Spectroscopy and diffrrential scanning calorimetry. The Fe and Sn coordination environments and the composition dependence of the hyperfine parameters on the Fe and Sn content have been fully discussed with respect to the solid dissolution alloying, grain refinement, and distortion caused or induced by mechanical alloying.
关键词:
mechanical alloying
,
null
,
null
Y.Q. Wu
,
X. Y. Yang and Y.B. Xu (State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)(Laboratory of Atomic Imaging of Solids
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
A cross-sectional sample of indentation in [001] silicon was made and a lateral microcrack beneath the indentation was observed by high resolution electron microscope (HREM). The HREM images around the microcrack tip show an alternate distribution of the amorphous and lattice structure. The crack does not propagate by the successive debonding between certain atomic planes, meaning that before a crack completely opens, there may be a stage of amorphization, resulting from severe distortion of lattice.
关键词:
amorphization
,
null
,
null
,
null
,
null
B.Z Cui
,
X. K. Sun
,
X.G. Zhao
,
W.Liu
,
Q.F. Xiao
,
T. Zhao
,
Z.D. Zhang andY.C.Sui(Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
The effects of the hydrogenation-disproportionation-desorption-recombination (HDDR) process on the structure and the magnetic properties of the mechanical alloying (MA) prepared Nd8Fe84 Ti8 alloy and its nitride counterpart have been studied in detail. It has been found that Nd(Fe, Ti)12Hδ is formed in the temperature range from 300 to 550°℃. The disproportionation is ready to start at 550°℃ and is complete at 960°℃.The desorption and the recombination are almost synchronized. The phase of Nd(Fe,Ti)7 is formed at 750°℃ during the HDDR treatment. With increasing temperature of HDDR process, the metastable structure of TbCu7 type is gradually transformed into the structure of ThMn12 type. The intrinsic coercivity and the maximum magnetic energy product increase with increasing temperature of HDDR process.
关键词:
Nd(Fe
,
null
,
null
,
null
