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LOW CYCLE FATIGUE BEHAVIOR OF AZ91HP ALLOY IN AS HIGH PRESSURE DIE CASTING

Z. Liu , Y. Y. Xu , Z.G. Wang , Y. Wang , and Z. Y. Liu State Key Laboratory for Fatigue and Fracture of Materials , Institute of Metal Research , Tile Chinese Academy of Sciences , Shenyang 110015 , China School of Material Science and Engineering , Shenyang Technical University , Shenyang 110023 , China

金属学报(英文版)

Fully reversed total strain-controlled low-cycle fatigue tests were conducted at room temperature in air to study fatigue behavior of AZ91HP in as high pressure die casting and subsequently heat treatments. All the specimens in different heat histories exhibited cyclic strum hardening in different degrees. It was difficult to distinguish the fatigue behaviors of the die-casting specimens from the solution-aging specimens. However the solution treated specimens showed longerfatigue life at high strum amplitude and shorter fatigue life at low strain amplitude than die-casting and the solution-aging specimens though they had the lowest yield strength with higher strain hardening. Fatigue fracture surfaces for strain amplitude larger than 0.005 showed very similar to those of the monotonic tensile tests. The SEM examination revealed that regions of fatigue crack growth and final fracture could be characterized by quasi-cleavage mech anisms, but some shallow dimples, slip bands and secondary cracks were found on the fracture surface in the fracturs crack growth areas.

关键词: low-cycle fatigue , null , null , null

Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

GLOBAL ENERGY-SPECTRA OF BANDS AND DENSITY-OF-STATES IN A CLASS OF 2-TILE SYSTEMS

Zeitschrift Fur Physik B-Condensed Matter

Electronic properties of a general class of one-dimensional two-tile systems are calculated exactly. The systems containing periodic crystals, generalized Fibonacci quasicrystals, generalized Thue-Morse aperiodic lattices and even other two-tile aperiodic lattices, can be divided into two different families which are constructed by the inflation rules: {A, B} --> {A(m11) B(m12) A(m21) (B(m22)} and {A, B} --> {A(n11) B(n12), B(n21) A(n22}, respectively. As typical examples, global spectra of bands and density of states in some two-tile aperiodic systems are numerically calculated. Some interesting properties are obtained.

关键词: generalized fibonacci lattices;renormalization-group approach;one-dimensional quasicrystals;space rescaling method;thue-morse;lattices;electronic-properties;quasiperiodic systems;aperiodic;systems;green-functions;cantor spectra

POLARITONS IN 3-TILE QUASI-PERIODIC SEMICONDUCTOR SUPERLATTICES - BULK AND SURFACE-MODES

Physica B-Condensed Matter

The bulk and surface modes of the polaritons in three-tile quasiperiodic semiconductor superlattices are investigated and evaluated numerically with a transfer matrix method. It is shown that the distribution of the polariton modes depends obviously on the structure of the quasiperiodic superlattice. Especially, the number of the bulk modes and the number of the surface modes are related to the number of layers and the number of interfaces contained within the quasiperiodic superlattice, respectively. Some modes of surface polaritons become resolved from the bulk modes with adjusting the constructure of quasiperiodic superlattices.

关键词: fibonacci superlattices;raman-scattering;systems

SPECTRAL STRUCTURE FOR A CLASS OF ONE-DIMENSIONAL 3-TILE QUASI-LATTICES

Physical Review B

Using a decomposition-decimation method based on the renormalization-group technique, we have studied the spectral structure of a class of one-dimensional three-tile quasiperiodic lattice models, for which the (concurrent) substitution rules are S --> M, M --> L, and L --> LS, where S, M, and L represent, respectively, the short, medium, and long tiles. Branching rules for the electronic energy spectrum have been analytically obtained and confirmed by numerical simulations. It is found that three kinds of branching patterns alternately appear in the spectrum, which displays a kind of self-similarity very different from the trifurcating self-similarity of one-dimensional Fibonacci quasilattices.

关键词: electronic-properties;quasiperiodic lattices;localization problem;fibonacci;quasicrystals;systems;states;maps

Nickel-free stainless steel for medical applications

材料科学技术(英文)

BIOSS4 steel is essentially a nickel-free austenitic stainless steel developed by the Institute of Metal Research, Chinese Academy of Sciences, in response to nickel allergy problems associated with nickel-containing stainless steels that are widely used in medical applications. The high nitrogen content of this steel effectively maintains the austenitic stability and also contributes to the high levels of corrosion resistance and strength. BIOSS4 steel possesses a good combination of high strength and toughness, better corrosion resistance, and better blood compatibility, in comparison with the medical 316L stainless steel. Potential applications of BIOSS4 steel can include medical implantation material and orthodontic or orthopedic devices, as well as jewelries and other decorations.

关键词: medical stainless steel;nitrogen;nickel-free;nickel-allergy;blood;compatibility;austenitic steels;high-nitrogen;corrosion;cells

Nickel-free Stainless Steel for Medical Applications

Yibin REN , Ke YANG , Bingchun ZHANG , Yaqing WANG , Yong LIANG

材料科学技术(英文)

BIOSS4 steel is essentially a nickel-free austenitic stainless steel developed by the Institute of Metal Research, Chinese Academy of Sciences, in response to nickel allergy problems associated with nickel-containing stainless steels that are widely used in medical applications. The high nitrogen content of this steel effectively maintains the austenitic stability and also contributes to the high levels of corrosion resistance and strength. BIOSS4 steel possesses a good combination of high strength and toughness, better corrosion resistance, and better blood compatibility, in comparison with the medical 316L stainless steel. Potential applications of BIOSS4 steel can include medical implantation material and orthodontic or orthopedic devices, as well as jewelries and other decorations.

关键词: Medical stainless steel , null , null , null , null

Thermodynamics Study on the Decomposition of Chromite with KOH

Z. Sun , S.L. Zheng , Y. Zhang , null , null , null , null , null , null , null , null , null , null , null , null , null , null

金属学报(英文版)

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.

关键词: chromite , null , null , null

Developing carbon materials targeted for applications-A summary on the annual world conference on carbon, Carbon2011

新型炭材料

The 2011 Annual World Conference on Carbon (Carbon 2011) was held in Shanghai, China, during 24-29 July, 2011. This conference was hosted jointly by East China University of Science and Technology, University of Shanghai for Science and Technology, and Institute of Coal Chemistry Chinese Academy of Sciences. About 800 attendees from 42 countries/regions participated in this conference, and 797 papers were accepted for presentation, including 5 plenary lectures, 42 keynote lectures, 280 oral presentations, and 470 posters, involving 10 topics: graphene; nanocarbon, carbon for energy storage and conversion, porous carbon and adsorption, carbon fiber and composites, precursor/carbonization and graphitization, computation and modeling, bio-carbon and safety, novel experimental techniques and characterization, bulk carbon and industrial applications. Research and development of nanocarbons are quite active and in particular, graphene received tremendous interest. Rapid progress has also been made on the electrochemical properties, energy conversion and energy storage applications of carbon materials.

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