Xinghao DU
,
Jianting GUO
,
Bide ZHOU
,
Liangyue XIONG
材料科学技术（英文）
In order to study the subboundaries evolution in superplastically deformed NiAl, the positron lifetime change during superplastic deformation process was measured. It is shown that the superplastic deformation of NiAl has not influence on its τ2, the newly recrystallized grain boundaries formed during entire superplastic deformation process belong to the calegory of subboundaries and have not contribution to the superplastic strain.
关键词:
NiAl
,
null
,
null
,
null
Jun SHEN
,
Zhuangde XIE
,
Bide ZHOU
,
Qingchun LI
,
Zhijun SU
,
Hongsheng LE
材料科学技术（英文）
A hypereutectic Al-Si alloy powder was prepared by ultrasonic gas atomization process. The morphologies, microstructure and phase constituent of the alloy powder were studied. The results showed that powder of the alloy was very fine and its microstructure was mainly consisted of Si crystals plus intermetallic compound A19FeSi3, which were very fine and uniformly distributed.
关键词:
Xiang XUE
,
Zhiliang NING
,
Bide ZHOU
,
Chunhui ZHANG
材料科学技术（英文）
In this study, the Solidworks was used as pre-processor, which performed the three- dimensional solid construction and automatic enmeshment. The COSMOS was adopted as post- processor to display the temperature distribution and further to simulate the thermal stress distribution of dies. A software package for three-dimensional temperature fields of complicated die casting and its dies was developed and the temperature distributions of a fan cover casting were simulated by the software.
关键词:
Yuebing ZHANG
,
Xiang XUE
,
Bide ZHOU
材料科学技术（英文）
This paper demonstrates the potential of a computer code, developed by the authors, in shaping gating systems by modeling the fluid flow phenomena through a complex gating system during mold filling. A plate casting with dimension 200 mm×200 mm×50 mm was chosen as the verifying problem. Water analog studies were carried out on this casting. The comparison indicates that computer simulation could be a powerful tool in shaping gating systems.
关键词:
Physical Review B
In order to understand the unusually large value of zero-field splitting D for the axial Fe3+ center in a KTaO3 crystal, Zhou made two assumptions in his recent report [Phys. Rev. B 42, 917 (1990)]. In this Comment we will show that his assumption II is qualitatively reasonable, whereas assumption I is unnecessary and doubtful.
关键词:
electric-field;srcl2
HAO Shiming SUN Rongyao Northeast University of Technology
,
Shenyang
,
China
金属学报(英文版)
A kinetic model for carbide diffusion coating has been proposed bused on the theory of steady diffusion and the sublattice model of solid solution.It is supposed that the growth rate of car- bide layer is controlled by the volume diffusion coefficient of carbon (?)s in carbide layer and the activity of carbon in steel substrate.The calculated results for V_4C_3 coating treatment of commercial steels T10.45,Crl2MoV,4Cr5MoVSi are in good agreement with the exper- imental data.
关键词:
diffusion coating
,
null
,
null
Journal of Physics and Chemistry of Solids
The layered ternary ceramics Ti3SiC2 and Ti3AlC2 are isostructural and can form Ti3Si1-xAlxC2 solid solutions combining the advanced properties of both compounds [H.B. Zhang, Y.C. Zhou, Y.W. Bao, M.S. Li, Improving the oxidation resistance of Ti3SiC2 by forming a Ti3Si0.90Al0.1C2 solid solution, Acta Mater. 52 (2004) 3631-3637; E.D. Wu, J.Y. Wang, H.B. Zhang, Y.C. Zhou, K. Sun, Y.J. Xue, Neutron diffraction studies of Ti3Si0.9Al0.1C2 compound, Mater. Lett. 59 (2005) 2715-2719; J.Y. Wang, Y.C. Zhou, First-principles study of equilibrium properties and electronic structure of Ti3Si0.75Al0.25C2 solid solution, J. Phys.: Condens. Matter 15 (2003) 5959-5968; Y.C. Zhou, J.X. Chen, J.Y. Wang, Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1-xSixC2 solid solutions, Acta. Mater. 54 (2006) 1317-1322]. In the present work, the solid solutions of Ti3Si1-xAlxC2 (x = 0, 0.25, 0.33, 0.5, 0.67, 0.75, 1) are investigated by first-principle calculations based on pseudo-potential plan-wave method within the density functional theory framework. The results show that as Al content increases in the solid solution, all the bonds have weakened to certain extents, which lead to an unstable structure both energetically and geometrically. The calculated results are compared and discussed with the reported data for the Ti3Si1-xAlxC2 solid solutions. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
ceramics;ab initio calculations;electronic structure;electrical;conductivity;oxidation behavior;mechanical-properties;ti3sic2;temperature;ti3alc2;air;si
ZHOU Jiankun LIU Xianghuai CHEN Youshan WANG Xi ZHENG Zhihong HUANG Wei ZOU Shichang Shanghai Institute of Metallurgy
,
Academia Sinica
,
Shanghai
,
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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null
Physical Review B
The assignment of the absorption spectrum of Y3Fe5O12 (YIG) made by Scott et al. [Phys. Rev. B 10, 971 (1974)] is shown to be incorrect and a new one is made by diagonalizing the complete cubic crystal-field matrices for d5 ions, involving spin-orbit interaction, given by Zhou et al. [Phys. Rev. B 44, 7499 (1991)]. The Racah parameters B and C, the crystal-field parameter Dq, and the spin-orbit coupling coefficient zeta are determined (in units of cm-1) as B = 783.3(530), C = 2928(3220), Dq = 1336(1300), zeta = 395 for octahedral Fe3+, and B = 606.1(705), C = 2696(2730), Dq = -1117.3(560), zeta = 335 for tetrahedral Fe3+, where the numerals in parentheses are the values adopted by Scott et al. Furthermore, the cubic zero-field splitting parameter a of Fe3+ in YIG is calculated to be a(oct) = 156 X 10(-4) cm-1 and a(tet) = 58.6 X 10(-4) cm-1. The value for a(oct) differs from the value of 189 X 10(-4) cm-1 found for Fe3+ in Y3Ga5O12:Fe3+. These results support speculations made by Geschwind [Phys. Rev. 121, 363 (1961)].
关键词:
fe3+;mn2+
