L. X. Li and D. S. Peng (Department of Materials Science and Engineering
,
Central SouthUniversity of Technology
,
Changsha 410083
,
China)
金属学报(英文版)
The deformaton behavior of Ti - 6Al - 4V alloy under hot - working condition has been studied by compression testing in the temperature range 750 - 950℃ and strain rate range 0.05 - 15s -1. The flow stress decreases with the increase of temperature and with the decrease of strain rate. After a steep initial strain hardening, a flow softening occurs. This softening is mainly ascribed to the temperature rise and dynamic recmptallisation.By a simple extension, a classical sinushyperbolic constitutive equation can be used to describe the flow behavior of Ti - 6Al - 4V alloy. flow stress is described as a function of strain, strain rate and temperature. The parameters Q, n andaare the same at differ- ent deformation conditions, and A is a funciton of strain.
关键词:
Ti-6Al-4V alloy
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null
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null
CHEN Yong
,
et al
钢铁研究学报(英文版)
The dynamic soft reduction technology for 360mm×450mm bloom casting and its application results at PISCO (Panzhihua Iron & Steel Co.) were presented. In order to analyze the influence of the soft reduction on internal defects of bloom, such as center porosity and central segregation, experiment for contrasting process with or without soft reduction for bloom was investigated. The operation shows that after applying the soft reduction of bloom alloy steel, the ratio of center porosity whose defect level is below 1.0 increased from 66.67% to 85.71%, ratio of central segregation whose defect level is below 1.0 increased from 94.44% to 100%, ratio of central shrinkage cavity which is free increased from 88.89% to 96.42%, and central segregation index of carbon decreased from mean value of 1.15 to 1.05. These results have provided important technology supports for PISCO to optimize the steel product structure, and to improve the production of high quality, property, and value added products.
关键词:
continuous casting bloom;dynamic soft reduction;alloy steel;internal quality
Applied Physics a-Materials Science & Processing
The terahertz dielectric response of LuFe(2)O(4) is investigated by terahertz time-domain spectroscopy over a temperature range of 6-290 K. It is revealed that besides the central mode associated with the charge-ordered state, a soft TO(1) mode at below similar to 240 K is identified indicating the existence of displacing ferroelectricity, in addition to the charge-ordering-induced ferroelectricity at below 320 K. The anomaly of the soft mode at similar to 180 K reflects the magnetoelectric correlation between the soft TO(1) mode and the spin/charge fluctuations revealed recently. Finally, the magnetic property at below similar to 240 K is discussed.
关键词:
system lufe2o4;charge;polarization
D.Eylon
,
S.R.Seagle
材料科学技术（英文）
The state of Ti research, development and industry is reviewed in this article. The fifty-year anniversary of Ti technology commercialization in the USA provides an opportunity for a historical perspective. Incorporation of "information-age" tools into alloy development, processing, and production invigorates the technology. Consolidation, diversification and globalization have been transforming the Ti industry in the recent years.
关键词:
Yanwu Xu
材料科学技术（英文）
Using mathematical plasticity theories, universal formability (UF) technology has been developed and applied in the automotive stamping engineering and production. As a formability analysis tool, this technology is the major methodology for the development of stamping expert system (solution provider) for (a) product design and feasibility analysis, (b) material automatic selection using nomograms, (c) draw die design using pre-models, and (d) UF and robustness analysis of die performance in finite element analysis (FEA) environment.
关键词:
G.Montay
,
A.Cherouat
,
A.Nussair
,
J.Lu
材料科学技术（英文）
Residual stress in coatings is the result of individual particle stress. Their effects may be either beneficial or detrimental, depending upon the magnitude, sign and distribution of the stresses with respect to the external load. Tensile stress which exceeds the elastic limit causes cracking in surface coatings or at the interface between the substrate and the coat. Compressive stress, in general, has a beneficial effect on the fatigue life, crack propagation, coating adhesion and on the durability of the top coat during service. Compressive residual stresses can increase the number of cycles before crack initiation begins through a mean stress effect. Temperature gradients which occur during solidification and subsequent cooling are the principal mode of internal stresses generation. Some parameters influence the residual stress field of both the coating and the substrate. Substrate nature, spraying temperature, thickness of the coat layer, substrate preparation (grit blasting conditions), and velocity of the splats are in the relation with the quality of the coating. In this work, we will describe the role playing by the ceramics coating elaboration on the residual stress gradient in depth of the component. The incremental hole drilling technique has been developed to determine the residual stress gradient in depth of the coat and substrate which must be used with particularly conditions. This new technology has been employed on zirconia, alumina and tungsten carbide plasma sprayed coating.
关键词:
Coating
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null
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null
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null
LIANG Yong LI Ruiguo Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
ChinaInstitute of Corrosion and Protection of Metals
,
Aademia Sinica
,
Shenyang
,
110015
,
China
材料科学技术（英文）
Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.
关键词:
laser
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null
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null
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null
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null
Journal of Solid State Electrochemistry
The microencapsulation technology was brought in to solidify corrosion inhibitor in order to prolong the releasing time of it. In this work, thiourea (H(2)NCSNH(2)) was used as a corrosion inhibitor and microcapsuled using glutin and polyvinyl alcohol (PVA), respectively, as protective agent. The re-sealing process was used as a way to prolong the releasing time of the H(2)NCSNH(2) encapsulated in microcapsules. It was found that the H(2)NCSNH(2) microcapsule corrosion inhibitor using PVA as a protective agent had a better releasing time. The releasing times of the H(2)NCSNH(2) microcapsule corrosion inhibitors were prolonged from 18 to 48 h by re-sealing process and using PVA as a protective agent. Both the use of PVA as a protective agent and the application of the re-sealing process decreased the encapsulation efficiency of the H(2)NCSNH(2). The performance parameters on protecting Q235 carbon steel from corrosion in 0.1-M H(2)SO(4) solution were evaluated by polarization curve and electrochemical impedance spectra methods. The results showed that the H(2)NCSNH(2) released into the solution from microcapsules could well protect Q235 carbon steel from corrosion and the corrosion-inhibiting mechanisms of it were the same as that of H(2)NCSNH(2).
关键词:
Microencapsulation technology;Corrosion;UV spectrophotometric method;Electrochemical impedance spectra;Polarization curve;carbon-steel;3-percent nacl;mild-steel;in-vitro;release;encapsulation;acid;microparticles;microcapsules;derivatives
材料科学技术（英文）
In this paper, radio frequency (r.f.) heating CVD technology for preparation of high performance fiber has been introduced. SiC, B fibers have been produced by this technology.
关键词:
