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Study on Enhancement Effect of Cavitation Caused by HIFU Piezoelectricity Transducer

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稀有金属材料与工程 2006年第S3期 527-529页

作者： Xinnan Fan~1 Changping Zhu~1 Shichuan He~2.Minglei Shan~2.Jiacai Chen~2.(1.Department of Computer & Information Engineering,Hohai {3.,Changzhou 2.3.2.,China) (2.state {2. laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai {3.,nanjing 2.0098,China)

An orthogonal ultrasonic irradiation system consisting of HIFU with frequency at 1.05 MHz combined with ultrasound with frequency at 2. kHz was applied in this *** of cavitation was detected by pH-value measurement and conductance *** result shows that the effect of cavitation caused by ultrasound with frequency at 2. kHz is greatly enhanced by HIFU piezoelectricity transducer with frequency at 1.05 MHz.

关键词： HIFU piezoelectricity transducer enhanced cavitation effect orthogonal ultrasonic irradiation

Diffusion of Hydrogen along the Grain Boundaries in Ni_3.l Alloys

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Journal of Materials Science & Technology 2001年第2期17卷 207-210页

作者： Xiaoying CHENG and Xiaojing WAN Institute of Materials research, Shanghai university, Shanghai 2.0072. China Qiuyun WU and Xiukui SUN {2. key Lab. for RSA, Institute of metal research, Chinese Academy of Sciences, Shenyang 110015, China Shanghai Univ Mat Res Inst Shanghai 200072 Peoples R China Chinese Acad Sci Met Res Inst State Key Lab RSA Shenyang 110015 Peoples R China

The diffusivity of hydrogen in two Ni3.l alloys (No.1 and No.2. has been measured in the temperature range of 100 degreesC to 42. degreesC using an ultrahigh vacuum gaseous permeation technique. The diffusivity data fall into two segments, in which the hydrogen diffusivity adheres to the Arrhenius form, respectively. From the hydrogen diffusivity, it is conjectured that the hydrogen diffusivity reflects the hydrogen transportation along the grain boundaries at lower temperature and the hydrogen transportation in the lattice at higher temperature. The intergranular fracture of Lit-type intermetallics induced by hydrogen at relative low temperature results from hydrogen transportation along the grain boundaries and not in the lattice.

关键词： Diffusion of Hydrogen along the Grain Boundaries in Ni3.l Alloys Al Ni

STUDY ON THE VIBRATION CHARACTERISTIC OF THE metal PUSHING BELT CONTINUOUSLY VARIABLE TRANSMISSION

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Chinese Journal of Mechanical Engineering 2001年第2期14卷 175-178,183页

作者： Yang Wei Qin Datong Li Yilong Zhu Caichao The state key {2. of Mechanical Transmission,Chongqing {3. 重庆大学机械传动国家重点实验室重庆

The solid and finite element model of metal pushing type continuously variable transmission are established at speed ratio of i =0 5 and i=2. 0. In order to solve the problem of the complicated of structure,the node node rod discrete finite element model is put forward and the whole system is simplified and *** natural frequency and mode shape of system are solved by iterative Lanczos reduce method for sensitivity analysis in finite element *** new method and the result can be used to improve the smoothness of the variable transmission system and to propose the theory for reducing noise at operation.

关键词： Continuously variable transmission Finite element model Modal analysis Vibration characteristic

CYCLIC DEFORMATION OF COARSE GRAINED POLYCRYSTALLINE PURE Al——Ⅱ.FRACTURE SURFACE MORPHOLOGY

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Acta metallurgica Sinica(English Letters) 1992年第5期5卷 330-335页

作者： XIA Yuebo WANG Zhongguang state key {2. for Fatigue and Failure of Materials,Institute of {3. research,Academia Sinica,Shenyang,China

SEM photos for very coarse grained and high ductile polycrystalline pure Al show following characteristics:A few fracture sources are concentrated,the crack propagates in fan-shape near them,and the fatigue striations are cyclic cleavage *** striation consists of a wide cleavage facet and a narrow cleavage *** stages often blunt due to plastic *** fatigue striations are clear and continual,and distribute over whole zone of stage Ⅱ crack *** kinds of fatigue striations form in different levels,are conjoined by a“twisted baked piece of pastry”*** secondary crack along the fatigue striations was observed *** of them have already developed into secondary macrocracks and secondary fatigue striations were found clearly on secondary fracture sur- *** fracture surface can be divided into two parts,initiation and propagation zone of the crack,however,no statical-fracture zone was *** mechanism to form striations was preliminarily discussed.

关键词： fatigue crack Al fatigue striation secondary crack cleavage tongue

A FLOW STRESS MODEL FOR AZ61 MAGNESIUM ALLOY

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Acta metallurgica Sinica(English Letters) 2004年第2期17卷 155-160页

作者： H.T.Zhou X.Q.Zeng Q.D Wang W.J.Ding state key {2. of {3. Matrix Composite,Shanghai Jiaotong university,Shanghai 2.003.,China state key {2. of {3. Matrix Composite Shanghai Jiaotong UniversityShanghai 200030China

The flow stress behaviors of AZ61 alloy has been investigated at temperature rangefrom 52. to 673. with the strain rates of 0.001-1s^(-1). It is found that the averageactivation energy, strain rate sensitive exponent and stress exponent are different atvarious deformation conditions changing from 143.6 to 176.3.J/mol, 0.12. to 0.167and 6 to 8 respectively. A flow stress model for AZ61 alloy is derived by analyzingthe stress data based on hot compression test. It is demonstrated that the flow stressmodel including strain hardening exponent and strain softening exponent is suitableto predicate the flow stress. The prediction of the flow stress of AZ61 alloy has shownto be good agreement with the test data. The maximum differences of the peak stressescalculated by the model and obtained by experiment is less than 8%.

关键词： magnesium alloy flow stress model hot deformation straion softening

CYCLIC DEFORMATION OF COARSE GRAINED POLYCRYSTALLINE PURE Ai——Ⅰ.SLIP CHARACTERISTICS

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Acta metallurgica Sinica(English Letters) 1992年第4期5卷 272-277页

作者： XIA Yuebo WANG Zhongguang state key {2. for Fatigue and Failure of Materials,Institute of {3. research,Academia Sinica,Shenyang,China

Comparing with ordinary ploycrystalline materials sized to μm grade,the slip morphology of the coarse grained polycrystalline pure Al is characterized by:(1)several slip domains occur in a grain,and in same domain,several slip systems operate at same time or one after another intensely,a beautiful and neat slip pattern is forming on the specimen surface;(2.for high Σ-value coincident and random grain boundaries,the grain boundary affecting zone (GBAZ),bout 50—12.μm wide,is favourable site to form intergranular crack at early fa- tigue life easily,and migration or slide of the boundaries were often *** low Σ-value near-coincident grain boundaries show a higher degree of slip continuity and strain compatibility than high Σ-value *** crack is not easily nucleated at low Σ-value near-coincident boundaries;and(3.due to suppression of grain boundary slip at triple grain boundary node,the high Σ-value and random grain boundary among the three boundaries of tricrystal crack easily during cyclic deformation.

关键词： coincident grain boundary random grain boundary intergranular crack boundary slide serrated grain boundary

Study on Microstructure and Mechanical Properties of Hot Rolled Low Silicon Containing Phosphorus TRIP Steel

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稀有金属材料与工程 2011年第S3期40卷 228-233页

作者： Hou Xiaoying, Xu Yunbo, Wu Di state key {2. of Rolling and Automation, Northeastern {3., Shenyang 110819, China Northeastern Univ State Key Lab Rolling & Automat Shenyang 10819 Peoples R China

The effects of final air cooling temperature on the microstructure and mechanical properties of hot rolled 0.2.-1.9Mn-0.5Si-0.08P TRIP steel were studied by utilizing OM, SEM, TEM and tensile tests. Experimental results showed that in the multiphase microstructure of the investigated steel when the finish rolling temperature was about 82. ℃ and the final air cooling temperature was in the range of 63.-700 ℃, the grain size of most of ferrite was finer (about 4 μm) and which had higher dislocation density, the bainite packets had chaotic orientations and lath boundaries of bainite were not quite straight, the retained austenite distributed in the ferrite grain boundaries or triradius was fine and dispersive, and their grain size was about 0.4-1.9 μm. With increasing the amount of ferrite, the volume fraction of retained austenite had a slight decrease. When the final air cooling temperature was 63. ℃, the steel had excellent mechanical properties, which was characterized by combination of continuous yielding, high strength (about 796 MPa) and high elongation (2..7%) as well as low yield/strength ratio (0.58); when the final air cooling temperature increased to 700 ℃, the matrix structure was bainite packets and the comprehensive properties were deteriorated.

关键词： hot rolled TRIP steel low silicon containing phosphorus microstructure and mechanical properties final air cooling temperature

BREAK-UP MECHANISM OF metal DROPLETS GENERATED BY AN ELECTROHYDRODYNAMIC TECHNIQUE

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Acta metallurgica Sinica(English Letters) 1997年第1期10卷 39-45页

作者： X.F. Yu Z.Q. Hu H.S. Hu Z Jiang and X. Liu(state key {2. of RSA, Institote of {3. research, Chinese Academy of Sciences, Shenyang110015, China)(Northeastern university Shenyang 110006, China) Inst of metal research Chinese Acad of Sciences Shenyang China

Nanometer powders can be produced by an electrohydrodynamic technique. The breakup mechanism of the metal droplets generated by the electrohydrodynamic technique was analysed. It showed that the applied voltage, the electric field Btrength, the properties of the molten metal and the volumetric flow rate of the molten metal directly effect the breat-up extent of the metal droplets.

关键词： electrohydrodynamic technique nanometer powden charged liquid droplet surface charge density

In Situ Synthesis of Nanocrystalline Intel-metallic Compound Layer during Surface Mechanical Attrition Treatment of Zirconium

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材料热处理学报 2004年第5期 1242-1246页

作者： SUN Cai-yun', Xffi Ji-jia ', WU Xiao-lei', HONG You-shi', LIU Gang \ LU Jian3. LU Ke2.1. state key {2. of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China 2. Shenyang National {2. for Materials Sciences, Institute of metal research, Chinese Academy of Sciences, Shenyang 110016, People's Republic of China 3. LASMIS, university of Technical of Troyes, 10000, Troyes, France

The surface mechanical attrition treatment (SMAT) technique was developed to synthesize a nanocrystalline (NC) layer on the surface of metallic materials for upgrading their overall properties and performance. In this paper, by means of SMAT to a pure zirconium plate at the room temperature, repetitive multidirectional peening of steel shots (composition (wt%): 1C, ***, base Fe) severely deformed the surface layer. A NC surface layer consisting of the intermetallic compound FeCr was fabricated on the surface of the zirconium. The microstructure characterization of the surface layer was performed by using X-ray diffraction analysis, optical microscopy, scanning and transmission electron microscopy observations. The NC surface layer was about 2. urn thick and consisted of the intermetallic compound FeCr with an average grain size of 2.±10 nm. The deformation-induced fast diffusion of Fe and Cr from the steel shots into Zr occurred during SMAT, leading to the formation of intermetallic compound. In addition, the NC surface layer exhibited an ultrahigh nanohardness of 10.2.GPa.

关键词： nanocrystalline intermetallic compound surface layer deformation diffusion