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Guided Waves in the Multilayered One-Dimensional hexagonal Quasi-crystal Plates

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Acta Mechanica Solida Sinica 2021年第1期34卷 91-103页

作者： B.Zhang j.G.Yu x.M.Zhang x.h.Wang School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo454003China

Guided waves in the multilayered one-dimensional quasi-crystal plates are,respectively,investigated in the context of the Bak and elasto-hydrodynamic *** curves and phonon and phason displacements are calculated using the Legendre polynomial *** characteristics in the context of these two models are analyzed in *** show that the phonon-phason coupling effects on the first two layers are the same at low frequencies;but,they are more significant on the first layer than those on the second layer at high *** obtained results lay the theoretical basis of guided-wave nondestructive test on multilayered quasi-crystal plates.

关键词： Multilayered structures Quasi-crystal plate Guided wave Phonon-phason coupling effect

ThE SEEPAGE ChARACTERISTICS OF hETEROGENEOUS BODY WITh DIFFERENT SPREADING SOLUTION MODES AND ITS APPLICATIONS

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Acta Metallurgica Sinica(English Letters) 2007年第5期20卷 363-372页

作者： h.j. Wang A.x. Wu x.S. Chen j. Zhang Civil ＆ Environment Engineering School University of Science and Technology Beijing Beijing 100083 China School of Resources and Safety Engineering Central South University Changsha 410083 China

As the dump was a typically heterogeneous body, the seepage was different with varied spreading solution modes. The phenomenon of lamination that occured in the site was simulated using three layers in an indoor experiment, and the seepage effect comparison experiment of the inside spreading solution model and the top spreading solution model have been carried out. In the inside spreading solution mode, the phreatic planar flew without infiltration and the parallel layer motion model was used to calculate the seepage coefficient and equivalent seepage coefficient of each state respectively. In the top spreading solution model, the phreatic planar flew with an even infiltration on the surface, and the vertical layer motion model was adopted to calculate the above coefficient. The results showed that the seepage coefficient of the inside model was larger than the top model in the heterogeneous body, The ratio of them was between 1.42 and 3.07. On the basis of these results, the following new technologies were discussed： installing a few small diameter mechanical pore sand piles with every lamination in the using dump; drilling some holes one-off in the unused dump. These two methods could changed the top spreading solution into the inside model, thus the seepage in the dump was improved.

关键词： heterogeneous body top spreading solution inside spreading solution sand pile drawing-injection drill

Machine learning guided automatic recognition of crystal boundaries in bainitic/martensitic alloy and relationship between boundary types and ductile-to-brittle transition behavior

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journal of Materials Science & Technology 2021年第25期84卷 49-58页

作者： x.C.Li j.x.Zhao j.h.Cong R.D.K.Misra x.M.Wang x.L.Wang C.j.Shang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China Department of Metallurgical Materials and Biomedical EngineeringUniversity of Texas at El Paso500 W.University AvenueEl PasoTX 79968USA

Gradient boosting decision tree(GBDT)machine learning(ML)method was adopted for the first time to automatically recognize and conduct quantitative statistical analysis of boundaries in bainitic microstructure using electron back-scatter diffraction(EBSD)*** spite of lack of large sets of EBSD data,we were successful in achieving the desired accuracy and accomplishing the objective of recognizing the *** with a low model accuracy ofxis-angle pair as characteristic features,the accuracy of the model was significantly enhanced to about 88%when the Euler angle was converted to overall misorientation angle(OMA)and specific misorientation angle(SMA)and considered as important *** this model,the recall score of prior austenite grain(PAG)boundary was~93%,high angle packet boundary(OMA>40°)was~97%,and block boundary was~96%.The derived outcomes of ML were used to obtain insights into the ductile-to-brittle transition(DBTT)***,ML modeling approach suggested that DBTT was not determined by the density of high angle grain boundaries,but significantly influenced by the density of PAG and packet *** study underscores that ML has a great potential in detailed recognition of complex multi-hierarchical microstructure such as bainite and martensite and relates to material performance.

关键词： Machine learning Feature engineering Automatic recognition Lath structure Crystallography

Phase-field modeling for anisotropic ductile damage of magnesium alloys at finite deformations

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journal of Magnesium and Alloys 2024年第7期12卷 2967-2984页

作者： C.xie x.K.he x.Liu j.h.Ye j.B.Chen Faculty of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211PR China Key Laboratory of high Temperature Wear Resistant Materials Preparation Technology of hunan Province Hunan University of Science and TechnologyXiangtan 411201PR China

The damage anisotropy of an extruded ZK60 Mg alloy is characterized using tensile tests and scanning electronic *** accumulation of anisotropic deformations leads to the great differences of the dimple evolution and strains at fracture along different loading *** introduce the anisotropic deformation information into the damage constitutive relationship,a thermodynamically consistent phase-field model of ductile damage fully coupled with elastoplastic finite deformations is developed in this *** the user-defined constitutive relationship and displacement-temperature coupling element,the finite element simulations are *** results show that:(1)ZK60 Mg alloys presents clear R-value difference in 0°,45°,and 90°tests of intact *** 45°test possesses the greatest R-value(1.50)and the greatest strain at fracture,however,the R-value for 0°is less than 1,indicating the thinning is preferential.(2)The higher ultimate stress leads to a larger average dimension of the dimples,whereas the higher density correlates with a larger elongation ratio at the *** disappearance of the stress-bearing area indicates that the phase-field assumption on stress degradation is completely compatible with the dimple analysis on fractography.(3)The simulation results of the stress-strain relationships and damage paths correlate well with the experimental ductile damage of magnesium alloys at 200◦*** errors are basically attributed to the modeling parameters and finite element iteration *** proposed model presents fine applicability and reliability for the predictions of plastic deformations,ductile damage,and fracture of anisotropic Mg alloys.

关键词： Ductile damage Anisotropy Phase field Constitutive relationship Magnesium

Ablation behavior of(ZrC/SiC)_(3)alternate coating prepared on sharp leading edge C/C composites by CVD

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journal of Materials Science & Technology 2022年第20期115卷 129-139页

作者： B.Li h.j.Li x.Y.Yao x.F.Tian Y.j.jia G.h.Feng State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi׳an 710072China

A(ZrC/SiC)_(3)alternate coating was deposited on sharp leading edge(SLE)C/C composites by chemical vapor deposition(CVD).The ablation behavior was examined via oxyacetylene torch with heat flux of 2.38 MW/m^*** results indicated that the alternate coating exhibited great ablation resistance,providing an effective protection for C/C *** initial rapid heating stage,the(ZrC/SiC)_(3) alternate coating can relieve thermal stress,avoiding the peeling of coating and keeping an intact coating *** subsequent ablation,the Si C layers in central region were consumed rapidly,leaving layered *** stacked ZrO_(2) layers were reserved with the assistance of the release of thermal stress by interspaces,offering a great anti-scouring *** transition and border regions,the alternate Si C layers can delay oxygen erosion of inner coating and C/C substrate by the formation of SiO_(2).It is believed that the results would be helpful for the design and application of anti-ablation coatings on SLE C/C composites.

关键词： Alternate coating ZrC/SiC Sharp leading edge Chemical vapor deposition C/C composites

A DUCTILE FRACTURE CRITERION BASED ON ThREEDIMENSIONAL VOID MODEL

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 227-234页

作者： j.K. huang x.h. Dong National Die ＆ Mould CAD Engineering Research Center Shanghai Jiaotong University Shanghai 200030China

A fracture criterion derived from a microscopic point of view is proposed and has proved to be effective in the analysis of uniaxial tension. On the one hand, a method of predicting a ductile fracture is proposed using a three-dimensional void model and the assumption of velocity discontinuity. The relationship between the void volume fraction and the critical strain to fracture, calculated with the help of the new model, shows the same tendency as that obtained from the modified Thomason model. On the other hand, the mechanical and metallographic analyses of the uniaxial tension experiment are performed using four kinds of carbon steel. The relationship between the void volume fraction and the critical strain to fracture, calculated from the new model, agrees better with the result obtained from the experiment, rather than that calculated by the modified Thomason model, which confirms the validity of the ductile fracture criterion based on the three-dimensional void model.

关键词： Fracture criterion Uniaxial tension Velocity discontinuity Mechanical and metallographic analyses

Chinese life cycle impact assessment factors

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journal of Environmental Sciences 2001年第2期13卷 205-209页

作者： Yang, j.-x. Nielsen, P.h. Research Cntr. for Eco-Envtl. Sci. Chinese Academy of Sciences Beijing 100085 China

The methodological basis and procedures for determination of Chinese normalization references and weighting factors according to the EDIP-method is described. According to Chinese industrial development intensity and population density, China was divided into three regions and the normalization references for each region were calculated on the basis of an inventory of all of the region's environmental emissions in 1990. The normalization reference was determined as the total environmental impact potential for the area in question in 1990(EP(j)90) divided by the population. The weighting factor was determined as the normalization reference (ER(j)90) divided by society's target contribution in the year 2000 based on Chinese political reduction plans, ER(j)T2000. This paper presents and discuss results obtained for eight different environmental impact categories relevant for China: global warming, stratospheric ozone depletion, acidification, nutrient enrichment, photochemical ozone formation and generation of bulk waste, hazardous waste and slag and ashes.

关键词： Environmental impact Global warming Life cycle Ozone Sustainable development

Structure evolution of the Fe_(3)C/Fe interface mediated by cementite decomposition in cold-deformed pearlitic steel wires

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journal of Materials Science & Technology 2022年第6期101卷 28-36页

作者： Y.T.Zhou x.h.Shao S.j.Zheng x.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin 300130China

Cold-drawn pearlitic steel wire is irreplaceably used in industry owing to its outstanding mechanical property which is dominated by the cementite/ferrite(Fe_(3)C/Fe) interfaces in the material. however, the fine structures of the Fe3C/Fe interfaces in the deformed wires are less known to date. In this work, transmission electron microscopic investigation was performed on the atomic structures of the interfaces with the Isaichev orientation relationship(OR) in the wires with progressive deformation strains. In addition to the effect of the dislocation/interface interactions, this work revealed that the deformation-induced partial decomposition of cementite plays an important role in the interface reconstruction during deformation. The interfacial carbon vacancies generated by cementite decomposition and particularly, the amorphization of cementite layers in the sample with ε > 1 could effectively annihilated the interfacial dislocations and consequently relaxed the interfacial stress. The correlations between the interface structure changes and the mechanical properties of the wires were discussed.

关键词： Pearlitic steel Cementite decomposition Interface structure Deformation Transmission electron microscopy

Uncovering the hierarchical clusters in the heat-affected zone of an electron beam weldedα/βtitanium alloy joint

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journal of Materials Science & Technology 2024年第7期174卷 120-132页

作者： C.xu x.h.Shao h.j.Yang M.Lv h.Q.Liu x.L.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Suzhou laboratory Suzhou 215028China Department of Mechanical Engineering Kyushu UniversityFukuoka 819-0395Japan Bay Area Center for Electron Microscopy Songshan Lake Materials LaboratoryDongguan 523808China

Using high-resolution transmission Kikuchi diffraction(TKD)and transmission electron microscopy(TEM),we examined the hierarchical clusters that form in situ in the heat-affected zone(hAZ),which are com-monly referred to as“ghost”structures,of bimodal titanium alloy Ti-5Al-2Sn-2Zr-4Mo-4Cr(wt%,TC17).The ghost structures are enriched with Al elements but poor in Mo and Cr compared to the surroundingβ*** results show that the ghost structure in middle-hAZ mainly consists ofα_(L)laths with a high-angle grain boundary,which exhibits the classic Burgers orientation relationship(BOR)with the host matrix,while it encircles theα_(P)grains in *** the ghost structure is evidenced to form via in-complete martensitic *** results further confirm that the ghost structure is composed ofαL and tinyβ_(L)laths with BOR,with the former being enriched with Al and poor with Cr and Mo,while the latter is the ***,twoα_(L)variant clusters with a check-mark morphology are fre-quently observed viewed along[0001]_(αL)//[110]_(βL)directions,which are dominated by the crystallographic and geometrical relationships betweenαandβ*** on the microstructural characterization,it is hypothesized that the ghost structure is transformed from the initialα_(P)phase,due to the coupling ef-fect of high thermal stress(which induces the formation of a large number of dislocations)and element diffusion caused by sudden temperature increase and plunge cooling in the hAZ during the welding pro-cess.

关键词： TC17 titanium alloy Electron beam welding(EBW) The ghost structure Transmission Kikuchi diffraction(TKD) Transmission electron microscopy(TEM)