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Transactions of Nonferrous Metals Society of China 2022年第2期32卷 513-523页

作者： Kai-di LI Xiao-ning HAN Bin TANG Meng-qi ZHANG Jin-shan LI State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Beijing Aeronautical Manufacturing Technology Research Institute Beijing 100024China

A crystal plasticity finite element(CPFE)model was established and 2D simulations were carried out to study the relationship between microvoids and the microplasticity deformation behavior of the dual-phase titanium alloy under high cyclic *** show that geometrically necessary dislocations(GND)tend to accumulate around the microvoids,leading to an increment of average GND *** influence of curvature in the tip plastic zone(TPZ)on GND density is greater than that of the size of the *** the curvature in TPZ and the size of the microvoid increase,the cumulative shear strain(CSS)in the primaryα,secondaryα,andβphases *** deformation in the prismatic slip system is dominant in the primaryα*** the distance between the microvoids increases,the interactive influence of the microvoids on the cumulative shear strain decreases.

关键词： crystal plasticity dual-phase Ti alloy microvoids high cyclic loading cumulative shear strain geometrically necessary dislocation

EQUIVALENT MODEL OF EXPANSION OF CEMENT MORTAR UNDER SULPHATE EROSION

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Acta Mechanica Solida Sinica 2008年第4期21卷 327-332页

作者： Jue Zhu Minqiang Jiang Jiankang Chen Mechanics and Materials Science Research Center Ningbo University Ningbo 315211 China State Key Laboratory of Nonlinear Mechanics （LNM） Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

The expansion property of cement mortar under the attack of sulfate ions is studied by experimental and theoretical methods. First, cement mortars are fabricated with the ratio of water to cement of 0.4, 0.6, and 0.8. Secondly, the expansion of specimen immerged in sulphate solution is measured at different times. Thirdly, a theoretical model of expansion of cement mortar under sulphate erosion is suggested by virtue of represent volume element method. In this model, the damage evolution due to the interaction between delayed ettringite and cement mortar is taken into account. Finally, the numerical calculation is results indicate that the model perfectly describes performed. The numerical and experimental the expansion of the cement mortar.

关键词： size effect microvoids expansion sodium sulfate attack

Influence of substrate temperature on growth of a-Si:H films by reactive facing target sputtering deposition

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Science China(Physics,Mechanics & Astronomy) 2010年第5期53卷 807-811页

作者： YU Wei,MENG LingHai,YUAN Jing,LU HaiJiang,WU ShuJie & FU GuangSheng College of Physics Science and Technology,Hebei University,Baoding 071002,China College of Physics Science and Technology Hebei University Baoding China

Hydrogenated amorphous silicon(a-Si:H) films were deposited by reactive facing target sputtering(FTS) technique with a mixture of Ar and H2 reaction *** transform infrared(FTIR) absorption,Raman scattering and ultraviolet-visible optical absorption are used to investigate the microstructure and optical properties of the deposited *** decrease of the concentration of bonded hydrogen,especially that of(Si-H2)n with increasing substrate temperature(Ts),was observed in FTIR spectra,suggesting the atomic density increases and the concentration of microvoids decrease in a-Si:H *** increase of both the short range order and the intermediate range order of amorphous network for a-Si:H films were verified by Raman scattering spectra,in which increasing Ts decreasing the band width of TO and the scattering intensity ratio ITA/ITO were *** above results clarify the effect of increasing Ts on the microstructure amelioration for a-Si:H *** reduction of disordered domains is correlated with the film growing process,where the increased surface diffusion mobility and etching of weak bonds is induced by increasing ***,analysis of optical absorption indicates that the films with a lower optical band gap and a narrower band edge can be obtained by this FTS technique.

关键词： hydrogenated amorphous silicon facing target sputtering structural inhomogeneities microvoids

In-situ three-dimensional visualization of dynamic tension deformation in ferrite stainless steels

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Baosteel Technical Research 2013年第4期7卷 56-61页

作者： ZHANG Zhixia BI Hongyun LI Xin Stainless Steel Technical Centre Research InstituteBaoshan Iron & Steel Co.Ltd.

An improved three-dimensional （3-D） experimental visualization methodology is presented tor evaluating the fracture mechanisms of ferritic stainless steels by in-situ tensile testing with an environmental scanning electron microscope （ESEM）. The samples were machined with a radial notched shape and a sloped surface. Both planar surface deformation and sloping surface deformation-induced microvoids were observed during dynamic tension experiments, where a greater amount of information could be obtained from the sloping surface. The results showed that microvoids formed at the grain boundaries of highly elongated large grains. The microvoids nucleated in the severely deformed regions grew nearly parallel to the tensile axis, predominantly along the grain boundaries. The microvoids nucleated at the interface of particles and the matrix did not propagate due to the high plasticity of the matrix. The large microvoids propagated and showed a zigzag shape along the grain boundaries,seemingly a consequence of the fracture of the slip bands caused by dislocation pile-ups. The final failure took place due to the reduction of the load-beating area.

关键词： three-dimensional (3-D) visualization microvoids in-situ dynamic tensile testing ferritic stainless steels