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| 1 | Low-Temperature Nitriding by Means of SMAT显示文摘The microstructure in the surface layer of iron and steel samples can be refined at the nanometer scale by means of a surface mechanical attrition treatment (SMAT) that generates repetitive severe plastic deformation to the surface layer. The subsequent nitriding kinetics of the as-treated samples with the nanostructured surface layer is greatly enhanced so that the nitriding temperatures can be reduce to 300 - 400 °C regions. This enhanced processing method demonstrates both the technological significance of nanomaterials in advancing the traditional processing techniques, and provides a new approach for selective surface reactions in solids. This article reviews the present state of the art in this field. The microstructure and properties of SMAT samples nitrided will be summarized. Further considerations of the development and applications of this new technique will also be presented. | W.P.Tong H.W.Zhang N.R.Tao Z.B.Wang J.Lu K.Lu | 2004 | 材料热处理学报2004，25，5： | 3 |
| 2 | Distribution of Be in a Ti-Based Bulk Metallic Glass Composite Containing B-Ti显示文摘In order to obtain a glassy matrix during quenching, Be is often selected as a constituent of the compositions of Ti/Zr-based bulk metallic glass composites(BMGCs). The in situ formed β phase in Be-bearing BMGCs was reported to be Be-free. However, a thorough investigation of the distribution of Be in BMGCs is still missing to date. In this work, the distribution of Be in a Ti_(47.5)Zr_(33)Cu_(5.8)Co_3Be_(12.5)(at.%) BMGC was studied by the secondary ion mass spectrometry(SIMS) and the electron energy loss spectroscopy(EELS).It is found that Be almost totally dissolves in the glassy matrix, but a very weak intensity of Be in β phase is still detectable by SIMS, and the content of Be in β-Ti is estimated to be about 0.3 at.%. Based on the recently established two-phase quasi-equilibrium of BMGCs, the distinct solubility of Be in the glassy matrix and in β-Ti has been explained. | L.Zhang W.Q.Li Z.W.Zhu H.M.Fu H.Li Z.K.Li H.W.Zhang A.M.Wang H.F.Zhang | 2017 | Journal of Materials Science & Technology2017，33，7： | 3 |
| 3 | Large deformation and wrinkling analyses of bimodular structures and membranes based on a peridynamic computational framework显示文摘In this paper,the quasi-static large deformation,wrinkling and fracture behaviors of bimodular structures and membranes are studied with an implicit bond-based peridynamic computational framework.Firstly,the constant and tangential stiffness matrices of the implicit peridynamic formulations for the nonlinear problems are derived,respectively.The former is con structed from the linearization of the bond strain on the basis of the geometric approximation while the latter is established according to the linearization of the pairwise force by using first-order Taylor’s expansion.Then,a bimodular material model in peridynamics is developed,in which the tensile or compressive behavior of the material at each point is conveniently described by the tensile or compressive states of the bonds in its neighborhood.Moreover,the bimodular material model is extended to deal with the wrinkling and fracture problems of membranes by setting the compressive micro-modulus to be zero.In addition,the incremental-iterative algorithm is adopted to obtain the convergent solutions of the nonlinear problems.Finally,several representative numerical examples are presented and the results demonstrate the accuracy and efficiency of the proposed method for the large deformation,wrinkling and fracture analyses of bimodular structures and membranes. | H.Li Y.G.Zheng Y.X.Zhang H.F.Ye H.W.Zhang | 2019 | Acta Mechanica Sinica2019，35，6： | 2 |
| 4 | New ductile laminate structure of Ti-alloy/Ti-based metallic glass composite with high specific strength显示文摘Bulk laminate structure of Ti-alloy/Ti-based metallic glass composite(MGC) was prepared by melting a preform of alternate stack-up foils in the high vacuum atmosphere. The composite demonstrates a good combination of yield strength(~1618 MPa), plasticity(~4.3%) and specific fracture strength(384 × 10~3 Nmkg^(-1)) in compression. The maintained yield strength results from the unique microstructure composed of the Ti layer, the solution layer with gradient structure and the MGC layer. Such a multilayer structure effectively inhibits the propagation of shear band, leading to the enhanced plasticity. Those extraordinary properities suggest that combining ductile lamella with brittle metallic glass(MG) by such a lay-up method can be an effective way to improve mechanical properties of MG. | D.Li Z.W.Zhu A.M.Wang H.M.Fu H.Li H.W.Zhang H.F.Zhang | 2018 | Journal of Materials Science & Technology2018，34，4： | 2 |
| 5 | A stabilized complementarity formulation for nonlinear analysis of 3D bimodular materials显示文摘Bi-modulus materials with different mechanical responses in tension and compression are often found in civil,composite, and biological engineering. Numerical analysis of bimodular materials is strongly nonlinear and convergence is usually a problem for traditional iterative schemes. This paper aims to develop a stabilized computational method for nonlinear analysis of 3D bimodular materials. Based on the parametric variational principle, a unified constitutive equation of 3D bimodular materials is proposed, which allows the eight principal stress states to be indicated by three parametric variables introduced in the principal stress directions.The original problem is transformed into a standard linear complementarity problem(LCP) by the parametric virtual work principle and a quadratic programming algorithm is developed by solving the LCP with the classic Lemke's algorithm. Update of elasticity and stiffness matrices is avoided and, thus, the proposed algorithm shows an excellent convergence behavior compared with traditional iterative schemes.Numerical examples show that the proposed method is valid and can accurately analyze mechanical responses of 3D bimodular materials. Also, stability of the algorithm is greatly improved. | L.Zhang H.W.Zhang J.Wu B.Yan | 2016 | Acta Mechanica Sinica2016，32，3： | 2 |
| 6 | Aerodynamic Sweeping Study and Design for Transonic Compressor Rotor blades显示文摘The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor compressor. The first part of the present study is concerning the sweep effect with straight leading edge.In this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards axially.The second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading edge.Its adiabatic efficiency is a little bit greater than that of the reference un-swept rotor. | N.X.Chen,H.W.Zhang and W.G Huang Institute of Engineering Thermophysics,Chinese Academy of Sciences P.O.Box 2706 Beijing,100080,China | 2010 | Journal of Thermal Science2010，19，4： | 2 |
| 7 | Convergence Estimates for Some Regularization Methods to Solve a Cauchy Problem of the Laplace Equation显示文摘In this paper,we give a general proof on convergence estimates for some regularization methods to solve a Cauchy problem for the Laplace equation in a rectangular domain.The regularization methods we considered are:a non-local boundary value problem method,a boundary Tikhonov regularization method and a generalized method.Based on the conditional stability estimates,the convergence estimates for various regularization methods are easily obtained under the simple verifications of some conditions.Numerical results for one example show that the proposed numerical methods are effective and stable. | T.Wei H.H.Qin H.W.Zhang | 2011 | Numerical Mathematics(Theory,Methods and Applications)2011，4，4： | 0 |
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