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
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
L. P. Xu
,
M. H. Xu
,
L. Li
,
Y.A. Min
,
X.Z Xuand R.H .Liu (Department of Materials Science and Engineering
,
Shanghai University
,
Shanghai 200072
,
China) (Shanghai No.5 Iron and Steel Factory
,
Shanghai 200940
,
China)
金属学报(英文版)
The composition of a bearing steel was designed for limited hardenability by use of Grossmann's method. A medium frequency induction Process was applied to heat bearings to ensure penetrant heating and suitable solving of carbon and other elements in the matrix. The hardened depth measured from the end quenching test samples and actual bearings matches well with the designed one.
关键词:
: bearing steel
,
null
,
null
K. Deng
,
Z.M. Ren
,
Y.B. Zhong
,
G.C. Jiang and S.M.Hu 1) School of Materials
,
Shanghai University
,
Shanghai 200072
,
China 2) Shanghai BAOSTEEL Group
,
Shanghai 200941
,
China
金属学报(英文版)
In this paper, coupling the quasi-3D numerical simulation of electromagnetic field and the experiments of continuous casting with soft-contacted mould with some metals such as tin, aluminum, copper and steel, the electromagnetic characteristics of continuous casting with soft-contacted mould is analyzed. It is shown that the electromagnetic pressure on the surface of billet is increasing with the rising of power frequency as a logarithmically parabolic function, with that of electric conductivity of billet as a power junction, and with that of the current in inductor as a parabolic junction.
关键词:
continuous casting (CC)
,
null
,
null
,
null
,
null
L. Li
,
L.P. Xu
,
R. Y. Fu and M. Zhang School of Material Science and Engineering
,
Shanghai University
,
149 Yanchang Road
,
Shanghai 200072
,
China
金属学报(英文版)
The factors of heat treatments were discussed, which affect the formability of two low carbon, low alloy steels. Experiment concerns mechanical properties, R-values, orientation intensity, texture internal friction and their relationship with annealing and ageing.
关键词:
form ability
,
null
,
null
,
null
,
null
G.C. Jiang
,
K. Tang
,
X.B. Zhang and K.D. Xu Shanghai Enhanced Laboratory of Ferrometallurgy
,
Shanghai University
,
149 Yanchang Road
,
Shanghai 200072
,
China
金属学报(英文版)
Model Investigation is the only feasible way to solve the problem about the component activities in concentrated multicomponent alloys and molten slags at present. The basic characteristic of SELF-SReM model is briefly introduced in this paper. It intends to give out the systematical value of component activities in the whole homogeneous region of a concentrated multicomponent melt, then to provide a reliable database for the description of the equilibrium conditions associated with metallurgy processes. For molten slags, the key issue is to distinguish the accuracy of thermodynamic properties in binary systems. The fundamental approach for this task is to link the microscopic bond structure and macroscopic activity based on both of the measurement of high tem- perature Raman spectroscopy and the corresponding computation simulation according to molecular dynamics and quantum chemistry.
关键词:
activity
,
null
,
null
,
null
Yuanda DONG and Xueming MA(School of Materials Science and Engineering
,
Shanghai University
,
Shanghai 200072
,
China)Yuanzheng YANG(Dept. of Mechanical Engineering(2)
,
South China University of Technology
,
Guangzhou 510641
,
China)Fangxin LIU and Genmiao WA
材料科学技术（英文）
Highly supersaturated nanocrystalline fcc Fe60Cu40 alloy has been prepared by mechanical alloying of elemental powders. The phase transformation is monitored by X-ray diffraction (XRD),Mossbauer spectroscopy and extended X-ray absorption fine structure (EXAFS). The powder obtained after milling is of single fcc structure with grain size of nanometer order. The Mossbauer spectra of the milled powder can be fitted by two subspectra whose hyperfine magnetic fields are 16 MA/m and 20 MA/m while that of pure Fe disappeared. EXAFS results show that the radial structure function (RSF) of Fe K-edge changed drastically and finally became similar to that of reference Cu K-edge, while that of Cu K-edge nearly keeps unchanged in the process of milling. These imply that bcc Fe really transforms to fcc structure and alloying between Fe and Cu occurs truly on an atomic scale. EXAFS results indicate that iron atoms tend to segregate at the boundaries and Cu atoms are rich in the fcc lattice. Annealing experiments show that the Fe atoms at the interfaces are easy to cluster to α-Fe at a lower temperature, whereas the iron atoms in the lattice will form γ-Fe first at temperature above 350℃, and then transform to bcc Fe
关键词:
